Moparts
Running hotter on highway !
Posted By: ademon
Running hotter on highway ! - 06/06/09 08:01 PM
in traffic it will stay around 180, expressway it will slowly creap to 190 - 195 never took it on the expressway for more than about 30 min so don't know how hi it will climb. it a 360 with 11.0 cr blocked heat risers single plane, j heads, 14 initial, 33 total msd ignition no vacuum advance, tti headers 2 1/2" exhaust, jetting looks good already played with timing and jetting with no diff, has 4 core 22" stock style rad thats clean, has stock shroud, 5 blade mopar 18.5" clutch fan out of 70's car, stock replacement water pump, belts tight, 160 t-stat, had 180 hi flow same problem. ??? I have a 7 blade "215" fan thats for my demon will this make a diff, even though my problem seems to be at 65 MPH?
Posted By: Pacnorthcuda
Re: Running hotter on highway ! - 06/06/09 08:05 PM
What you're describing is not overheating...not even close
Posted By: DAYCLONA
Re: Running hotter on highway ! - 06/06/09 08:16 PM
When the needle starts hitting 220, you worry,....at 250 WORRY!
.....the 190-195 is fine, just the engine being worked!
Posted By: FurryStump
Re: Running hotter on highway ! - 06/06/09 08:18 PM
Mines runs better at 200-205. 205 at 75 mph on highway.
Posted By: 70RR383
Re: Running hotter on highway ! - 06/06/09 11:09 PM
I was having the same problem.Took it to my radiator guy,he looked down a pulled the belt right off the pully driving the waterpump!!!It was so loose it would slip at high speeds.It was shot.I had 3 or 4 guys look at my car and none of us noticed it.You never know,easy fix.
Posted By: ahy
Re: Running hotter on highway ! - 06/06/09 11:40 PM
If not a slipping belt, it may be a sign the radiator is starting to get plugged. Enough capacity for idle/low speeds but not enough when the engine is working. Agree 190-195 isn't overheating but running hotter on the highway is unusual.
Posted By: DAYCLONA
Re: Running hotter on highway ! - 06/07/09 12:55 AM
Quote:
Agree 190-195 isn't overheating but running hotter on the highway is unusual.
not if your running 3:91/4:10 gear or small diameter tires with high gears, and pulling down some healthy RPM, temps going to rise in that case
Posted By: RobX4406
Re: Running hotter on highway ! - 06/07/09 04:11 AM
Running a forward facing hood scoop?
Posted By: ademon
Re: Running hotter on highway ! - 06/08/09 05:32 AM
Ya, sealed to carb, 3.55 gear 25.3" tires, pulls around 3 to 3200 rpm's 65, 70mph. I know 195 is not overheating just kind of odd with the thick 4 core, shroud, 5 blade clutch fan, ect.. ect.. that it would still climb, just wondering what if i go on a 1 or 3 hour expressway trip.
Posted By: SomeCarGuy
Re: Running hotter on highway ! - 06/08/09 05:39 AM
When was the last time it was tanked or rodded out?
I bet you have sand in there.
Posted By: ademon
Re: Running hotter on highway ! - 06/08/09 04:00 PM
it been in the car for about 7 or 8 years about 7k miles, Change the antifreeze yearly,
Posted By: 318 Stroker
Re: Running hotter on highway ! - 06/08/09 04:25 PM
Mine was running hotter at highway speed than around town. At the suggestion of a Mopar friend, I installed a spring in my lower radiator hose, and that solved the problem...
could be sucking the lower hose closed
check for a spring in it
add one if its not in there
also check flow of rad
a/c or non-a/c ?
right pulleys with the right # of vanes on the pump?
I bump all my 5 blade fans up to 7 blades on a themo fan clutch
changing the anti freeze yearly is good but does not mean it will not have settament in the core of the rad
do you back flush it when changing the freeze?
does not sound bad right now..but it could be heading that way on the temp rizing up at speed
Posted By: aarcuda
Re: Running hotter on highway ! - 06/08/09 05:15 PM
Quote:
could be sucking the lower hose closed
check for a spring in it
add one if its not in there
also check flow of rad
a/c or non-a/c ?
right pulleys with the right # of vanes on the pump?
I bump all my 5 blade fans up to 7 blades on a themo fan clutch
changing the anti freeze yearly is good but does not mean it will not have settament in the core of the rad
do you back flush it when changing the freeze?
does not sound bad right now..but it could be heading that way on the temp rizing up at speed
I never understood the bottom hose collapsing theory.
Coolant heats up and pressure BUILDS in the system. My hoses are pumped up from the pressure. To think that a water pump could cause a vacuum where there was once 8-15 psi pressure seems unrealistic to me. I bet you had a bad cap or low fluid.
Posted By: stumpy
Re: Running hotter on highway ! - 06/08/09 05:19 PM
It can and does happen. The water pump moves a lot of fluid quickly. If the hose is weak it will suck shut.
no, a rubber hose gets weak over time
they all used to have a spring in them,but todays rubber is more stiffer,heat,oil,ozone resistant and last longer,there for will not suck flat as often...but they can and do...even a new one can,IMO
the pressure cap help build presssure and combind with anti freeze raise the boiling point, the pressure helps force the water into the small passages to keep hot spots/steam pockets from forming in the heads
the pump does move a good bit of water at idle,but when the revs go up,its sucking harder than it can push the mass of water through the restrictions in the engine cooling sytem
the sucktion build up and sucks the hose closed
I use a sainless wire so it does not rust my self and wrap it around something a little smaller that the ID of the lower rad hose,I make it long as the hose
I have dug a many of rusted up pieces of spring from out of the pumps and even had some wraped around the impellers over the yrs
with a weak hose you can stand there and rev the engine by hand and watch it suck closed
seen this on ferds,chibbys,and mopars
Posted By: Magnum
Re: Running hotter on highway ! - 06/08/09 09:08 PM
I suspect the radiator. It's not the fan. At 65mph the fan is of no importance.
While I also would not worry about 15 deg over my thermostat temperature. A proper cooling system should ALWAYS stay at thermostat temperature unless you have an electric fan and you are stopped, waiting for it to come on.
Posted By: plumebody
Re: Running hotter on highway ! - 06/08/09 09:58 PM
Could also be a blocked coolant passage in the heads. Been there done that
Posted By: aarcuda
Re: Running hotter on highway ! - 06/08/09 10:02 PM
Quote:
no, a rubber hose gets weak over time
they all used to have a spring in them,but todays rubber is more stiffer,heat,oil,ozone resistant and last longer,there for will not suck flat as often...but they can and do...even a new one can,IMO
the pressure cap help build presssure and combind with anti freeze raise the boiling point, the pressure helps force the water into the small passages to keep hot spots/steam pockets from forming in the heads
the pump does move a good bit of water at idle,but when the revs go up,its sucking harder than it can push the mass of water through the restrictions in the engine cooling sytem
the sucktion build up and sucks the hose closed
I use a sainless wire so it does not rust my self and wrap it around something a little smaller that the ID of the lower rad hose,I make it long as the hose
I have dug a many of rusted up pieces of spring from out of the pumps and even had some wraped around the impellers over the yrs
with a weak hose you can stand there and rev the engine by hand and watch it suck closed
seen this on ferds,chibbys,and mopars
i agree that the hoses today seem sturdier but if you have a weak hose, why geta spring for it. the spring may keep it from collapsing but the right fix is a new BETTER hose.
Plus, for suction to happen in a closed system, you need a restriction. if the bottom hose is collapsing and the top hose is pressurized, then I'd say your radiator is clogged all to heck and coolants not flowing.
here the guy is running normal temps but he's worried. theres no need to worry about the temps he posted so theres no real reason to suspect a problem with anything in his system- even the springless bottom hose
Posted By: Chilort
Re: Running hotter on highway ! - 06/09/09 01:13 AM
Does it creep up and come back down as the t-stat modulates? If it doesn't do that, then I WOULD worry. Sure, it is at an OK temperature but if it isn't controlling as it should then something is going wrong. Is it going to lead to a catastrophic failure today? Probably not. But it is an indication that something in the system is not balanced where it should be.
I'm not sure exactly how, because it really shouldn't matter at highway speed, but I had a thermostatic fan clutch that worked around town but failed on the highway.
Also, I've seen very large variation in the temperature readings produced by various temp sending units. If you, or a friend, has an infrared thermometer -- laser guided temp gun (I have a friend that works in HVAC though I think you can pick them up at Home Depot these days for around $50) then you might want to use it to verify the temps you are seeing. Just because the gauge shows one thing doesn't mean everything is working like it should (annoyingly).