heating up on freeway

[gr868]

what causes a gradual rise in temp when driving on the freeway is it lack of airflow or lack of coolant flow or fan slowing down incoming air? any thoughts thinking of buying new aluminum radiator but i don't know if this is the problem?

[MuscleRodz]

what engine, what radiator, what fan, shroud, no shroud???? could be as simple as an undersized or clogged radiator, or something more involved

[gr868]

oh sorry brand new 355 mild cam vortec heads maybe 375 horse 3.42 rear gears and turbo350 trans also new 4 row copper and brass radiator rodded out recently when engine went in twin junkyard electric fan setup with shroud wired to come on at 160 degrees

[gr868]

oops forgot 160 degree thermostat too thx

[JEFFTATE]

How high does the temperature get ??
195' ..210'....225' ???
A lot of people think that a car is supposed to run the exact same tempurature as the installed thermostat.
195' or 200' operating tempurature will not hurt anything.

With a TH350 and 3.42 gears , you'll be turning some rpms on the freeway. That'll build more heat anyway.

Do you have a way to keep hot engine compartment air from being pushed down under the car at highway speeds and being pulled back through the radiator.
The high pressure air under the hood gets pushed under the car.( It has nowhere else to go )
And can be pulled back through the front of the radiator because of the low pressure zone just behind the front spoiler.
The hot air rushes up there and gets pulled back through the radiator.( It could be a contributing factor. )

It sounds like you are just generating more heat than the radiator can dissipate.

Also check your ignition timing ,timing marks on the balancer , and associated marks on the front timing cover.
Make sure the timing mark on the balancer is correct , in relationship to actual TDC of #1 piston.
If your timing is wrong , the engine will generate more heat.
This has thrown more than one person for a loop while looking for a cooling system issue.
Just because the balancer , timing cover , etc.. is new , doesn't mean that its correct.

[Vegas69]

Fan on at 160 is a little premature and can effect cooling down the freeway. Many radiator manufacturers put in rubber valves for the air to pass through the shroud instead of the fans. I have dual fans with no valves and have no problems but I don't turn that much rpm either. I'd unplug the fans and take it for a cruise down the freeway and see what happens first.

[gr868]

timing is good i just built the engine so i verified the balancer in relation to tdc and yes the engine turns almost 3k on the freeway so perhaps just to much extended rpm/heat to dissapate it gets to about 200 degrees on a 20 minute run but is still slowly climbing i have a fiberglass yenko hood with a scoop in it so i dont think air is being pushed back through the radiator i think i will put a switch in so i can control the fans on the highway like vegas69 mentioned and see if that helps or hurts do you think an aluiminum radiator will help? i really want to drive the car on a road trip but am worrried it will overheat

[ProTouring442]

timing is good i just built the engine so i verified the balancer in relation to tdc and yes the engine turns almost 3k on the freeway so perhaps just to much extended rpm/heat to dissapate it gets to about 200 degrees on a 20 minute run but is still slowly climbing i have a fiberglass yenko hood with a scoop in it so i dont think air is being pushed back through the radiator i think i will put a switch in so i can control the fans on the highway like vegas69 mentioned and see if that helps or hurts do you think an aluiminum radiator will help? i really want to drive the car on a road trip but am worrried it will overheat

I'm guessing this is a 1st gen Camaro? When on the road, turn on your heater, full blast. If this lowers the temp, then it is most likely a radiator problem (not enough radiator, too small, or clogged).

Shiny Side Up!
Bill

[Roadbuster]

I had the same thing happen - then the thermostat failed. It is a pain to check but better than getting stuck. The thermostat that failed was only a year old and very few miles.

Jon

[gr868]

i forgot to say i am running the transmission lines through the radiator via the stock built in cooler i am wondering if this is my problem i do have a seperate cooler to use i will try that over the weekend

[ProdigyCustoms]

9 out of 10 times when it heats up on the ointerstate or under continous load, it is bad or to small radiator. The fans are useless on the high. No fan can pull as much air as your forcing through the radiator at speed. Unless your grill is restrictive, which Camaro grills are not normally restrictive.

[L n L]

Probably your radiator.

I had a '67 Firebird, with a 469" Pontiac. Like you, I ran 3.42 gears and a THM350, but I had tires a little over 27" diameter. Converter was semi-loose, it would stall up to 3200 or so, but was surprisingly tight at light throttle. Car ran lower 11's at close to 120.

I had a BeCool aluminum radiator, FlexALite Black Magic shrouded fan, and a CSR electric waterpump.

With all of that, at ~70-75mph on the highway, I would run right at 194 degrees. I would have to believe that your smaller motor would run even cooler.

Lee

[orange69]

i have had a camaro do this ended up being the lower radiater hose was sucking shut at highway speed found out by revving engine and seeing the hose colapes replaced hose with spring in it and problem gone

[ProTouring442]

I have had a Camaro do this ended up being the lower radiator hose was sucking shut at highway speed found out by revving engine and seeing the hose collapses replaced hose with spring in it and problem gone

Good point. I had thought about this, but usually this causes an overheat problem and not a gradual heat up.

Shiny Side Up!
Bill

[Josh]

Good point Orange69. Frank it right on. This is not a fan or shoroud problem at all. Radiator is too small (does not seem likley) or it is sludged up, thermostat stuck closed, collapsing hose or air flow through grill blocked.