Thermostat or...

Hey guys, fresh 440, 11.5-1, indy top, good size factory radiator running twin high cfm fans and electric water pump, just fired and run down the road for 15 miles yesterday and its getting up in temp, we pulled up at 205 to let it cool and then headed home. No thermostat at the moment, has a washer in it with a 5/8+ hole.
Is a 180 thermostat going to be better ?

Are your fans pushers or pullers? Can't tell in the pic. I always run a 180* stat. If your fans are pullers, you should have a shroud that covers the core competely.

Take the washer out. you do not want less flow, you want more. Putting a washer in the coolant flow is like putting a piece of cardboard in front of the radiator with a 6" hole cut in it.

take washer out and try again . I don't run a tstat in my Satellite . have mopar performance clutch fan and 12"electric on front of radiator

Tex

treed darn it

Tex

Yes Rick they are fully sealed pullers

But a thermostat reduces the flow as well

Yes they do, but not down to a 5/8ths washer hole restriction.

A thermostat is not designed to make it run cooler, it is designed to make it run hotter than it would without one.

Yes a thermostat is designed to get the engine up to a desired temperature range and keep it there.

hi
use a 180 stat and make sure you have the wire spring in lower rad hose !

I've seen just the opposite in the Mohave desert in SO CA, cars with no thermostats ran hotter in the summer than they did with one in it both 160 and 180 F made the cars run under 220 F when they where running hotter than that with no stat before trying one
The consensus was the coolant wasn't spending enough time in the radiators to allow heat transfer into the outside hot air
How where the Winternationals and Pomona ? PM me on this

That´s not needed with an electric water pump.

As said toss the washer (in your head see how much less the 5/8 will flow as opposed to your 1.5/1.75 rad nipples for instance). Use a good (Milodon?) high flow stat 180 or 185 to get the eng out of the cold/fast wear zone as quickly as possible. If the washer ain't it (& I'd be surprised if it ain't) then as said the fans are inadequate or are blocking airflow. I'm assuming the rad was flowed or at least checked out a bit (running a garden hose in it is a good backyard test for flow). Holler how it turns out.

This is all wrong. Most here don't understand how a cooling system works. A lot is trial and error, but some type of a restriction is needed for most systems. You have to slow down the flow so it stays in the radiator long enough to dissipate the heat. If it just flows threw it cant pull the heat out of the water. if the fans and water are efficient for the application then the radiator is not pulling enough heat out and you would need a more efficient core. I am not a big fan of electric water pumps and fans for for street use. I find that a good belt driven pump and clutch fan shroud and good rad is all that is needed for street.

A fresh engine may be a little tight and possibly run hotter. 205 doesn't sound all that bad.

FWIW...Meziere says not to use a thermostat w/ their electric water pumps.

I am a cause and effect type of guy. So it's a new build, let me ask a few questions. what's the total timing? do you have a vacuum advance on distributor? if you do is it hooked to ported vacuum or manifold vacuum.


Joe

This is my favorite topic of all of them. You cannot have too much flow. The "not spending enough time in the radiator" will cause it to get hot is not true. Either that, or all of the heat transfer studies, research, and papers written at the University of Minnesota (the leading school on heat transfer) since 1887 are wrong.

The physics in that radiator, are the same as the physics of a radiator on the moon. I say this as there will be others that will list exceptional examples to this theory. But physics are physics.

That is all easy for me to say, I've a friend whose engine overheats and just can't figure out why yet.

Best of luck to you.

Two simple reasons engines overheat*, not enough radiator, not enough air moving through the radiator.







*This is assuming no other problems, timing, water pump moving enough water, other mechanical problems.

Sorry, but you are giving out bad information. The last thing you want in a cooling system is a flow restriction. Keeping the coolant in the radiator longer also leaves the coolant in the block and heads longer, where it gets hotter. Now the radiator has to remove more heat from the coolant. Do we restrict it more, and let more heat into the coolant?


As said above, it's either an airflow issue or a coolant flow issue.

I've always taken a thermostat and "gutted" it and use it that way. I use a Moroso Electic motor with a alum water pump though.

Verify your temp gauge too. Wouldn't be the first time that 205 indicated was 190 actual.

Kevin

I have fixed a lot of cooling problems just by getting more air through the radiator. Wen you say "fully sealed" I assume you mean there is some type of shroud causing air to be pulled through 100% of the core. And that the fans are of sufficient size and CFM rating. I would take the restriction out and try it as well.

With an elec. water pump I run a gutted t-stat and no issues........

FWIW I had an expensive set of twin fans with a full shroud around them and the car would always peg the gauge if caught in traffic. Put a stock clutch 7 blade fan on with no shroud at all (cuz I didn't have one to fit the rad) and it's tons better. Still need to find a shroud that fits to finish it.

Last one I did I used 2 Spals with a full shroud but it was an aftermarket aluminum rad. They move a lot of air. Went from cooking itself to can't get it hot. Belt driven pump, no stat or restriction.

No not you Cab. That has been debunked for years. In a closed system more coolant flow is better. The radiator size, material of construction and fan rating are the only determiners of cooling system capacity. Like has been posted a thermostat is to insure quick warmups.

There is absolutely nothing else that need be said.

so, why when a car starts to run hot, does revving the engine( speeding up coolant flow) help to bring the temp down, vs letting it idle( slowing down the coolant flow)?

Well thanks guys but seems this is 3 ways, with thermostat, with centre cut out of it and totally open hahaha, guess I just give it a go.
We will be on it this arvo so Ill post tomorrow how we go.




Hi Joe, 35 total and locked up. Flame away

I will do Kev, thanks.

I will be shocked if it works without restriction but it is what we will try first
PS, the fans are good and proven with 1000's of street machiners down here, they are from a late model ford.

Hey Thumper, cant see the gutted stat working as the hole will not be much different to what i have.

Um, Oxy, restriction is a negative in this problem. Its a widely held believe, but not true.

As I kinda mentioned, heat transfer has been studied in detail, right here in Minnesota (get it?) since 1887. I don't think they are wrong.

There is no doubt that people might put in a restriction and "fix" the problem. But it didn't defy physics nor the research. It did something else to change the outcome. Turbulence aids heat transfer, as in more flow. You can't have too much flow.

As I said I will try it with nothing in first, if it runs cooler then i'll be happy and amazed .

UPDATE, Took the restriction out, the washer tack welded to the gutted thermostat was probably closer to a 3/4 hole, anyway with nothing in there we headed down the road and there was no real change, we went a little farther traveling at 50-60mph and seen nearly 215 on the gauge.
Hot afternoon here though at 95 and with a new'ish engine I guess we are struggling.
Will try the 180 thermostat next .

You have other issues. A thermostat won't fix it.

Well, the water pump is great, the fans are great, the radiator is good condition large Chrysler unit, the block is not filled and there is NO bubbles in the in the rad when running with the cap off.
Im lost.

Al ,
I had a mates 440 do the same thing . Man it got almost scary hot up to 225 or so .
Anyway .
I tried :
jack up rear of bonnet to help air flow , marginal gain
different waterpump and even pump housing , no change
thermostat and no thermostat , no change
checked the 16" puller electrical fan , nearly blew me over
I was about stumped .
Final resort put an old heavy Mopar fixed 6 blade mechanical fan on it , no shroud .
Could not get the motor to warm up !!
Now as he likes to rev and occasionally race it I put a thermostat in it and a flexlite 7 blade flex fan with a modified Camaro shroud.
Car now runs mid 180's unless a hot day in traffic .
Sometimes the electrical fans simply do not pull enough air no matter the advertising .
Low speed overheat = look at the fan
High speed overheat = look at airflow and coolant flow - radiator condition/size
Over 35MPH airflow should be enough that you don't need a fan .
That airflow can be through the radiator core as well as airflow out of engine bay .
A 3 or 4 core radiator can be as bad as a blocked core for airflow and heat dissipation .
With my sixpack bonnet if I run the air plate on the street the motor runs hotter
Good luck

Tex

Cheers Tex, You will know the fans, they are the twin AU Falcon fans, car also has a new 950cca battery and a 140 amp alt, we will keep at it.

No thermostat, belt driven clutch fan, '65 radiator.

Oh ok Al . They are normally good .
No mechanical fan with an electric waterpump
Like I noted check air flow out of engine bay . Do you have a scoop ?
I have seen cars in the shop with aftermarket electric fan shrouds to have airflow reduction . That is why some euro cars have flaps on the shroud , lets plenty of airflow at speed .
If the car is idling bonnet shut from cold does it quickly or slowly build up heat ? ie does it take 5 mins or so to get to 200F or 15-20 mins ? or longer ?

Tex

Probably only 5 mins to get to 200 yesterday but as I said it was a hot/humid day at 35 !!

No scoop at the moment, just a hole thats too big for air cleaner

5 mins to 200F is way too quick . even on a 35deg day . mine takes a lot longer than that .
run a probe in top tank to confirm temp .
hole in bonnet will let hot air out , can you feel any air flow with fans operating ?
I know its a pain but can you fit a mechanical waterpump to try ?


Tex

sounds like you have a flow issue still.. either
the radiator is too small or is plugging up..
a good radiator will run fine on the street at
50mph without a fan(has enough air flow)

Sorry Tex the 5 min to get to 200 was driving not sitting idling,
Yes with the fans, if you put your hand in front of the radiator you can feel heaps of air pulling through.
I will double check the gauge.
Not an easy thing to change over to standard water pump but I do have an Ali one somewhere.

Even driving that is too fast . Feel air flow past air cleaner out from under bonnet .
You will have to make sure radiator is fully clear , testing with a hose wont show much even if half blocked . Water will flow where it can .
Are these items previously used and ok then ?
You may even have to check waterpump flow rate .
Also check actual voltage at pump and fan . Seems less likely fan is faulty if it keeps heating up at road speed above 50klm hour

Tex

I agree

Tex

UPDATE.......

Car has done around 400 mile now and we are still running totally open.
Big change was dumping the coolant, flushing and filling with water and one bottle of Redline Water Wetter, it dropped 20 !!!!!!
FIXED

nice result . I must say I use Water Wetter and race additive - no glycol but rust inhibiter . No anti freeze/anti boil

Tex

The minute the air temperature in my yard is 180° I'll take the thermostat out. Unless you live on a volcano that's not happening.
Until then, all running w/o a t-stat does is pollute the oil, increase sulfuric acid content, increase ring wear, and wash down the walls with rich mixture.

Polyspheric, Do you understand that we have been trying to get the temp DOWN to 180-190 ? Yes I know that a cold engine is not good and would never beat on it until the temp is up.
Now we will look at controlling the temp with the thermo fans.

If you had a overheating issue they say that Water Wetter works best with straight water, no other coolants .

Yes , but , i also want an inhibiter in the system . Its not coolant.
Glad its worked out .
PS , i have not run a tstat for years . As my cars are dailys plus strip . I can live with it taking a little longer to warm up , i am concerned about not getting up to temp and pulling high rpm with tstat not open at track
A long time ago a radiator repairer/builder told me here in Sydney , like Perth , its not so hot or so cold we really need anti freeze or anti boil additives

Tex

So a long warm up is a good thing?
The thermostat is not your problem.

Yep. A long warm is a killer.

As poly says, the thermostat is not your problem.

You didn't actually sort out your cooling issue. You just threw everything at the wall and hoped it fixed it.

Make it run with a thermostat and your engine will thank you.

Dont forget I have an electric water pump and electric fans so I can leave them OFF during warm up, probably warm it up quicker than a thermostat .

FWIW. Indy headed 540, Meziere remote pump, no thermostat, no restrictor, 26" alum. radiator, shrouded puller fan. Street driven.
On hot days it ran 210-215. After installing a remote fan type transmission cooler, it now runs 190-195. Removing that heat source from in front of the radiator made that much of a difference.

I had an electric pump and fan on the street and the car would run cool around town but would climb to about 220 as soon as I got on the highway.
Now being a tech for over 30 years told me it was a flow issue,air and or water through the rad. I took the electric pump and fan out and installed a belt drive pump and 1 to 1 pulleys with a 5 blade viscous drive and viola!!! 180 degrees on the highway. Now thats with a 180 stat and a simple factory type deal with no shroud even.

Gus