Thanks in advance to all. Thanks Moparts

I'd Look first at getting a good shroud. Your primary issue is inadequate airflow.

This can be confirmed with even a cheap fan zip tied to the radiator. If it cools down at idle when you turn the fan on, there you go.

On my 49 Dodge truck, I had to remove the factory motor driven fan because there wasn't enough clearance between the radiator and the water pump (you get that with putting a V8 and different chassis under old sheet metal).

My local Car Quest had a high CFM single 16" electric fan that has adjustable temp settings for the cooling speed settings. I bought the 16" fan because it fit the vary tight confines of the location it had to fit in and matched the height of my very small 4 core core Champion radiator. There is a temp range between the turn on and the turn off you can't adjust, but you can choose the high/low range of the operating temp. The fan comes in a kit with the fan, temp control thermostat, and a wiring kit. Its attached to the radiator with those radiator zip tie things and there are a few choices on how to mount the temp probe for the thermostat. This system has been on the truck for a couple of summers now and seems to be working well. You will need to make a shroud for it to work on your radiator, or there could be larger diameter fans (or a dual fan) system available. My point is, adjustable temp electric fan kits are out there. When mine kicks on, you can watch the temp drop on the temp gauge. It only runs a minute or two when the coolant temp hits your high temp range, and shuts off when it reaches the low temp setting. I have mine is wired through the ignition switch so it only runs when the motor runs, but it can be set up to come on ( and turns off) when ever the temp limits are hit.


With that said, making a very good fan shroud for your existing system may actually solve your cooling system problems. You really need to pull as much air through your radiator at idle speed as you can, and your current half azz shroud isn't doing the job. If the good shroud doesn't solve your issue, you can then simply buy the adjustable electric fan to replace your existing fan size.

https://board.moparts.org/ubbthreads/ubbthreads.php/topics/2485313/1.html

you can read hear on the mercedes cooling fan and the controller created for it.
it cools quite well.

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I'm wondering if a smaller pump pulley to speed up the air/water flow would be a solution

Had a similar deal with a pretty stout 512" RB in a Duster; it would hit 200 or so in traffic.
Added a shroud to its aluminum radiator, and a smaller pump pulley.
Never got over 180 after that.
Also: prior owner had an electric pusher fan - which blocks airflow - and I removed it.

Most agree that air flow is the issue. Having been in this position before, I'll offer a suggestion that has worked for me; I go to a pick-a-part yard and pull a fan from an 80s Dodge pick up. It is too large in diameter to fit in the shroud. But, it's aluminum so it's easy to cut down, is lighter than the steel fan you have now, and it's balance isn't hurt much with the trimming.

Those fans move a LOT of air. More blades and more pitch to boot so it gets a clutch due to the additional drag. I have used this on several Mopars with no down side. Currently I have one on the 540 Hemi in my Cuda and it still has the original re-cored radiator with a good shroud.

And, if it matters, this route is cheap.

i'm certain a lot of people have the same or similar problem that the OP has; i do for one. so, what smaller pulley would be recommended?

Got a pic of this?

I'm not good at posting pics, but I'll try.

Here's one I already had. Such as it is. When I get a chance, I'll try to get a bit better shot or two.

Here's a pretty thorough dive into cooling systems.


https://www.enginebasics.com/Engine%20Basics%20Root%20Folder/Engine%20Cooling.html

I would try a 160 stat first and go from there

All a thermostat does is set the minimum temperature. It will do nothing for overheating.

Generally speaking, and by design intent, a thermostat does regulate minimum coolant temp.
But if the cooling system has enough capacity & flow capability, a cooler thermostat can bring operating temps down.
I did that on my Dually, and it definitely runs cooler.
That said, it also has an added ATF cooler and its factory oil cooler.

I forgot to add in a previous reply that water rejects heat a bit better than anti-freeze.
If the OP's climate allows it, I'd also drop the anti-freeze ratio to 25%.
At the track of course, no anti-freeze.

I have the opposite problem in my stockish 67 383 Coronet. Runs hot on highway and cools off as soon as I slow down.

Sounds like you need a thermostat
I've seen that in the past living in the Mojave desert in the summertime in and driving in the daylight

needs more radiator (or current one rodded out)

or you have an airflow blockage at higher speeds, or you have a colapsing lower hose at speed.

Yep. almost always a coolant flow issue...not an airflow issue

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Verify what pulleys you have.

Call Glen Ray

Maybe Not. I had the exact same issue with my 477 Hemi I had a new large Be Cool radiator, very high-flowing shrouded electric fans and still ran hot at idle only. I changed my pump to a High -flow Flowcooler Pump and Robertshaw High-flow Thermostat because I suspected the problem was low coolant flow at idle. The overheating issues were gone after that. I'd try those two first as they are way less expensive that new radiators and fans.

Lots of different problems can cause issues with cooling, huh

mine as well. most of our old rides came with a 185 or more commonly, a 195 degree thermostat. and as has been said, that is the minimum temperature. 200 to 210 will not harm these engines as long as the cooling system is up to task, and the engines oiling system is as well.
yes, i know it ain't 1967.
but if you are looking at your factory instrument cluster telling you your engine is 180 degrees, or the needle is pointing toward the "L" or possibly slightly more in the "middle" of the range sweep, you better take that with a grain of salt, as those indications were just generalities at best when new.
unless you have taken some time to precisely calibrate them to a "master" gauge/thermocouple, and this CAN be done, you are just playing tiddlywinks.
if it doesn't steam like a freight train, or puke coolant all over the ground when shut off, it ain't hot.
remember, this is just my OLD MAN opinion and my OLD MAN life experiences with [very] close to 60 years playing strictly with, and learning what i know now of, the Mopar brand of vehicles.
YOUR mileage will CERTAINLY vary.........

Define "after a while" also what is the ambient temp and other conditions like bumper to bumper traffic or ?.

Have you verified the readings with a thermocouple or RTD to a digital readout?
I have seen NEW "quality" gauges be off by as much as 40 degrees at the top end

removed advice because it upset people who have supernatural engineering insight

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I'll agree
With some saying coolant /air flow, try increasing the RPM to 1.5-2K. You will be generating more heat but also moving more air and coolant. it's another data point EDIT: and is simulating driving down the road as far as water flow is concerned, less heat will be generated as the motor is not under a load, HOWEVER more heat will be trapped under the hood

I "start" getting nervous with a know accurate reading until 220°. The general rule is 230° is the danger point and exceeding that may lead to internal damage and that it will definitely occur by by 245°. There are a lot variables due to clearances, components used etc. How hot does a top fuel motor get by the end of it's 1/4 mile run?
I have always gone straight to a thermocouple which is coupled to a laboratory grade digital temp meter. The thermocouple is placed as close as possible to the t/sat and inserted directly into the coolant. One can get extension leads so the meter can be placed on the seat if desired. Many will use surface probes or IR guns. IMO, they should be used as an indicator ONLY as they are rarely accurate.

I have calibrated factory gauges (what a PITA). And as previously mentioned I have seen brand new "name brand" gauges be whacked out of the box. Both electrical and mechanical. Voltage and grounds can affect the electrical ones Interesting tidbit, the gauges always seem to off on the high end and the warmer the reading the further off they are.
I do know from doing the factory gauges, there are two adjustments for the high and low reading. It may test your patience as the "pivot" point between the two is not in the middle. (Think off an offset center on a balance scale).
So adjusting one end, affects the other but not by the same amount that's the patience testing part. I would imagine if one
does so on a regular basis they may develop a "feel" for it or they may be a piece of equipment that the gauge repair people know of.
The gauges are thermally activated by the current passing through the gauge windings. Should someone want to try this themselves, a small box with a clear face will be needed as any air moving by the area will skew the readings, ( IE: walking by, picking up anything off the bench etc.). This does not occur in the car as the gauge is inside the cluster Allow 5 minutes or 1/2 a beer between adjustments for the gauge to "stabilize"

From my engineering days:

I can tell you 100% water cools better but is prone to corroding and freezing ( DUH)
50/50 has a higher boiling point, doesn't freeze except in EXTREME temps
100% propylene glycol will not cool as well but will lower the freezing point

The differences? Clearances, efficiency, materials used, and technology. That's not to say that a 67 engine built with todays technology would be any different. To the OP, way to many variables to answer with any certainty IMO

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If this were my issue I would get out the infrared temperature gun and find where the overly hot or overly cool areas are. A few years ago I had my '68 RR overheat and puke coolant only when I parked it and it heat soaked. Thought the 26" radiator was good and could see good coolant flow looking in the cap opening, had a new water pump and thermostat, good fan shroud, the right pulleys and everything in order. Pulled into my good friend's driveway and sat there for a few minutes and started puking coolant. He went to his toolbox and pulled out the infrared thermometer and the lower 2/3rds of the passenger's side of the radiator was stone cold as it was plugged. I couldn't believe it. Re-cored it and no issues even with a cammed engine and A/C. Get the infrared temperature gun out and start checking where your issue might be.

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Overdrive the water pump. No slower than crank speed if you can’t overdrive it. Never EVER run the pump slower than the crank unless you are shifting at 8k or higher.

A 4 core radiator is a bad move.

We had lots of good info posted, including some that was deleted. Hopefully some of it will be put to use.

If you remove the stat you need to put a restrictor in it's place, water full flowing thru the block/heads is not going to do what it is supposed to do ... transfer the heat from the iron as efficiently as possible.

Personally it's a test that is wasting your time and effort as you aren't going to leave it that way.



Describe what you consider a reasonable amount of time is please ...

i've fought bad temperature gauges and sending unit reading higher and lower than the actual internal temps were. I now check all suspicious cooling problems with two different heat temp guns to mak esure what the gauges are reading are accurate.
I had one of Autometer expensive race mechanical 320 degree reading on the face temp gauges reading 140 F when I could put my hand on the thermostat housing it wasn't hot at all, sticking my finger in the radiator with the electric water pump circulating the water found it below body temperature
Trust but verify

i agree with Cab on checking your gauges with a heat gun.
new parts these days are suspect to me, no matter who or where they are made.
it seems nobody has "pride in workmanship" these days............
if one disagrees with me on what is considered "hot", that's ok ! i know what works for me, and if something works for another and they are happy with it, no problem.

Personally, days at a time. An engine shouldn't get hot just idling in traffic.

But I'm not the OP, maybe he can tolerate 5 minutes before passing himself.

I agree airflow is a likely culprit with the circumstance you describe. But not for certain:

If it has an automatic trans, the heat generated from the converter due to the high idle of a cammed up engine and/or a loose converter can cause the coolant temp to rise from the trans cooler in the radiator. I recommend testing by installing a remote trans cooler and disconnecting the one in the radiator. Or you can drive in traffic and keep popping it into neutral when you are on the brakes to reduce heat from the trans and see if that helps.

Also, what is your timing at idle and off idle, at the RPM that the overheating occurs? It should be at least 20, preferably more, and if you have a operating vacuum advance hooked up to manifold vacuum, that helps too.

What is your base ignition timing. May need more initial/then limit total.

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195-200 isn't overheating, or even running hot.

Didn't

So, much ado about nothing.

I agree.

We ran these old mid - late 60s Mopar motors on a dirt track. 220 is nothing to be concerned about, but it is time to look for a possible problem. After a hard race on a hot evening, our motor often was at 220 by the time it got to the pit stall. Like most others, we were spraying the radiator down as soon as we could get to it as it entered the pits, as soon as the temp started to drop (which was very quickly) we went on to our spot and shut it off. 230 is the shutdown range if the temp isn't dropping really soon (even warm water across the radiator core drops the motor temps fast), 230 could cause the rings to start to loose their tension and could cause a loss of power, long term, and if done multiple times. 235 is shut it down now time. Then let the thing peculate until its below 180 and you still are probably OK, if it becomes a regular feature, I pulled the motor down for inspection.

so

Before changing anything I would try more initial timing.

h
hi
move your timing up to 16 deg inital . 34 total


what is the comp ratio ?

my 511 hemi runs perfect temps < 180 stat >in hot weather. 10.5 comp pump gas

26 in 2 core alu rad with shroud and clutch fan .

timing is every thing !

This ... auto trans ?? If so what is your convertor stall ? Where is your trans cooler , and do you have an auxiliary cooler also , factory hemi /auto trans cars did .

Also you said 35 total , is that what it runs best at ? I've been watching a lot of auto related tech these days and the 2nd gen hemis are said to not need as much total as a wedge headed engine ???

I don't doubt for a second that you have a coolling problem as it's creeping up and not stopping- I'm not sure why anyone is telling you 200/205 is ok when it's still climbing. sounds like 200/205 just happens to be the point where you have had enough and stop the madness, not a steady running temp for long periods.

However, it's probably worth looking into if your gauge is correct. Clearly it's accurate enough to tell you that a cooling issue exists but as you embark on the journey of thermostats/fans, etc, it's worth having an accurate reading as you will be comparing engine temps to thermostat open temps vs. size of fans and rads. The temp data point should be as accurate as possible.

the factory gauge in my 68 charger decided to be 30 degrees off after sitting for a loooonnngggg time. A gauge I calibrated many moons ago and I know it was correct back then as 230 and climbing triggered my car's gag reflex and she'd spew all over the ground. Old mechanical gauges, old wiring, old mechanical 5v limiter- old cars, man


I've been down this road with a mild big block in my charger. I believe I have finally solved it with high flow 160 thermostat, a very large fluidyne radiator, opened up core support, dual 1300cfm spal fans, flow kooler waterpump. I'm running a sniper efi that controls the fans individually. It will idle at rock steady 168-170 on just one fan with mid 50s ambient. the proof will be in the pudding soon enough.

many years ago before I ran this setup I ran a be cool direct fit which seemed like a joke to me. this was before the web was a good resource and I picked it out of the summitt catalog. very small rad. best results I ever had with that was no clutch, ghetto flex fan, and a cobbled together shroud.

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Runs

Who, and how , was that timing spec figured out ?

The flowkooler is for sure very different than a stock style pump. Many more smaller straight vanes on it. I chose it because I'm running a serpentine setup that turns the water pump in opposite direction than stock.

if you end going with electric fans, be careful what you choose. Seems like the CFM ratings they claim are optimistic at best. for example, I run spal 12" fans. rated at 1360cfm each. draws 18 amps. Derale makes a 12" 2000 cfm fan that draws 24 amps. then you go look at some other 12" fans that ive never heard of before.... they claim to move 2000 cfm and draw 9 amps? Even if they had some miracle design, I can't see them outflowing mine by 68% at 50% less amp draw... at 40% of the price to boot! come on!

If it was running well at that timing it wouldn't be over heating.

of all the electric fans out there, i choose OEM units every time. they are super reliable, pull fantastic air, and are relatively easy to wire up.
choose one that fits your radiator size, and make sure your wiring system is up to the task and in perfect condition.
don't be afraid to look at all makes and models to choose a fan setup.
just my opinion. your mileage will vary.

[

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Yes

It's free and only takes a couple of minutes. Why not try it it can't hurt and you may be surprised. Instead of telling evrybody they're wrong and being sarcastic about it.

Note that for fans, there are (2) spec for current draw..
1 is for the Turn-on surge and 1 is for continuous running.
1 thing to keep in mind is the total current draw which often very high that many don't realize the overall battery/electrical system drain.

Just my $0.02...

Sounds like you should be telling us how to cool your car down. Could make for an entertaining thread…

I can only speck to my experience with my hemi. It would start to get hot sitting in traffic fine on road. I changed the timing from 12 idle with advance to 32 locked out and now can sit in traffic all day in 100 degree weather.

Don't you just love guys that have all the answers but can't figure out their problem.

The OP has spent more time on here telling us we are wrong that it would have taken to just check and report back useful data rather than snarky crap.

I say let Mr. Knowitall figure it out on his own,

Don't you just love guys who contribute nothing but take up space. This is a non productive argumentative post that I had hoped to avoid. Reported to administrators but I guess it's there forum, their choice. I got some great suggestions and thanks to those that submitted them. I'm done with this here because of two legged rectums.

Damn

Are you still "overheating"?

You reported it to Tom ??? Lighten up Francis

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So I called Flowkool and talked to a female and passed along to a male. Told them both at cold start and gauge at zero, the gauge would climb in temp as the car warmed up.(normal) The gauge would run to about 192 then settle back at 189 and then stay steady at 192 regardless of sitting or running down the highway. (about 74 degree's outside temp) This caught My attention as the old pump and stat would run up to 190 and then settle back to 160 and then again raise to about 175 when cruising and would climb to over 200 if stuck in traffic for a time. The gauge would drop back to 175 after traveling a few hundred yards. . I asked flowkool about this and both people stated VERY FIRMLY that I have a bad temp gauge. [censored]. The temp reading on the gauge actually are similar to me as a new car as when driving My 2018 Ram the gauge goes to 220 and stays there regardless of temp or if I'm towing a loaded one car trailer.

Original stat is a 180 milodon. I bought the 180 flowkool to keep the setup all Flowkool. I'm going to go to the milodon and see what happens. I'm not very happy with the "experts" at flowkool.

One question I got from the male was..."the gauge must be bad as it reads 192 at start" How the heck did he get that ?

if i missed this at the start, please forgive me. [just an old man wondering through the cobwebs of my mind........ good title for a movie or a song, eh ? ]
did you try a different brand gauge and it's corresponding sending unit ? [i know you tried a different sending unit with your existing gauge]
did you try a known good mechanical gauge ? [if there is a place to install it.]
how about using an infrared heat gun to check the top and bottom of the radiator, as well as the heater hoses, to get some idea of how hot the engine is actually getting ?

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Every thermostat I've ever tested (that would be several), there is almost always vary a few degrees from one stat to another of the same brand and temp. Mass production causes that. Could be as much as 5 degrees difference between two thermostats of the same degree from the same company.

That said, different thermostat makers have differing opinion on what a 180 stat should operate at. Some believe the stat should be wide open at 180, but others believe they should start to open at 180. It should be pretty obvious the actual operating temp is going to be different between those two beliefs.

Gauges and sending units fall into the same pit. Mass production has allowable variations. Then add that some gauge manufactures have less concern about quality controls in both the gauge accuracy and the sending unit accuracy and then you get the market we have today. Unless you have very expensive, liquid fill, certified gauges, and sending units, I have serious doubts your gauge really has the ability to accurately determine a coolant temp difference of a couple degrees one way or the other. It may consistently give you the same numbers, but its anyone's guess if that number is dead accurate.

The car is either overheating or its not. Usually if its overheating, everyone knows. Its puking antifreeze, making funky noises, and everything is hot. Even if its not overheating, you may not like the numbers your gauge shows. That can usually be adjusted to some degree using various methods, but don't let your panties get into a bunch over a few degrees difference between two different thermostats of even the same brand. The purpose of a thermostat is to maintain a consistent running temp and eliminate the higher and lower temps, once the system has stabilized. If its doing that its functioning correctly. Then if running on the highway, or in stop and go traffic causes dramatically different experiences, fix them.

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Maybe you should readjust your idea of normal.

Flow Kool doesn't make thermostats. They sell Rober Shaw thermostats. It sounds like it might be worthwhile to try a different stat to see if you can get the temp stabilized down to where you want it.

192 plus or minus is a good place to be, and if it's doing that during any activity you partake in, let it alone.
trying to get something to stay at 160 might be the racer's trick for every last hp, but will only lead to build ups of acids, water, and other things in the oil you do not want.
the heat is necessary to burn that stuff off and keep your engine healthy.
if it's not puking, steaming, snapping and cracking, or other overheating symptoms, you are golden.
at one time, i believed in the "keep it at 160" as well, but after almost 60 years of playing with engines, i now like higher temperatures, even on our typical stuff, and i don't get concerned until something gets to around 230ish for a bit.
even 200 or 205 in stop and go traffic doesn't bother me. if your cooling system is good, nothing to worry about.
i am on the higher end of the temperature scale than some are comfortable with, but after all these years, i have had few if any problems doing so.
just my life experience. your mileage will vary.

[qu

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X.

You

That was hardly confrontation. It was just a possible suggestion that normal may have changed with updated parts. Could be that the pump and stat are working more efficiently. Don't be so sensitive.

Mr Know it all grabbed my backpack.

lol

Interesting thing about those factory Mopar temp gauges (and add the oil pressure gauges as well) is that back in the early 60s, they seemed to be pretty accurate, but by the end of the 60s and into the early 70s, that accuracy went right out the window. Those nationally imposed emission standards of 1968 almost instantly required higher motor operating temps to meet them. That was about the point all the manufactures dumbed down the factory gauge accuracy. Too many people were complaining about the cars running hot, the easy fix for them was alter the temp gauge readings. The reason the higher operating temps are upon us is because of the ever increasing emission standards up to the point the operating temps started effecting the life of the motors. That was the point better designed motors became a reality, Those better designed motors started showing up about the 2000 model year vehicles. The current crop of new motors are design controlled by bean counters trying to save a few cents on everything they can. Save a nickel on every car you produce may not sound like much until you build a few million vehicles, that is a lot of nickels.

The old designed motors seldom reached 200 degrees, remember water that is not under pressure boils at 212 degrees, add cooling system pressure and that boiling point can get up near that 260 degree mark. Detroit started pressurizing the cooling systems in the late 1940s. Thank the old Ford flat head V8s for that. Any old motor built after about 67 has better materials to withstand the higher temps the manufacturers knew was coming. Unless the motors that are older then 67 have problems, it would be a challenge to get them up much over 200 degrees with a pressurized system. Those motors and cooling systems were designed to keep the motors cooler then anything built after 67 or so. Those high performance big block motors of the late 60s caused a lot of temporary challenges for the car companies, at a time they were trying to raise the coolant temps to meet emissions. Suddenly big motors with increasing power, put into smaller packages with air flow restrictions, hit them all at once. That pretty much describes the late 60s and early 70s.

so

"Correcto"
Folks will spent $hundreds on cooling system parts to fix heating issues,
But don't have, or use, an infrared temp gun.
Being so cheap these days, they should be as common as an adjustable wrench.
Best "tool" to have when questioning accuracy of gauge, digital or analog.

The IR guns are good for an indicator but not always accurate unless calibrated to the surface they are reading. Better yet use a thermocouple and know for sure, Most cheap DVM's come with them

03/21/23 02:36 PM


Mike

so

I agree.

The old $99 top of line Sears Craftsman Infrared units had the added plug to compare its reading to thermocouples, and could adjust the ‘emissivity”.
similar to this unit:

https://www.amazon.com/Thermometer-...NXJFF8/ref=psdc_9931459011_t2_B00EXYPVG2

The way all things digital are declining in price I hope our low end cell phones will soon have thermographic ‘pit viper vision’ display at no added cost.

Even troubleshooting electrical devices it is useful to have “pit viper vision”.

Let me try this again. We all agree you can't have too much air flow, BUT, some think you can have too much coolant flow? Not so, just a bad rumor that will NEVER go away.

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[i]
"Really. To much or fast flow rate may not give the radiator the time it needs to do its job. Thats not a rumor]" See, this is why it will never go away. The University of Minnesota has been the premier leader in the engineering of heat transfer since 1884.

No one in the study of heat transfer there at the U of M would agree with you. Either they are wrong, or the physics in your radiator are different than other places in the universe. I can't help but be sarcastic, as this has come up too many times. Think about it.....you can't have too much air flow, but you can have too much fluid flow??? I'm going with what they teach in engineering school.

Now, someone will come up with a story on how this guy did this or that and it proves I'm wrong. No, something else is going on in all of those cases as nobody gets to defy the laws of physics....anywhere in the universe. Good luck with the heat issue.

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You last line there is perfect, and is exactly what happens when the fluid moves slowly.

But, it doesn't matter, no one ever wins an argument even in the face of facts. Have a good day.

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I wonder if what you are seeing is because the fluid is not flowing slow enough to extract the heat? It would be interesting to see a comparison of AFR and EGT numbers as it was vs. how it is now ...

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