Two weeks ago I took my Vette for a in city 30 mile trip. Coolant and oil temps went to 236 degrees. Outside temp was 75 degrees. Warm for Seattle. Sounds to high for my liking. Yesterday I took the same route and temps were 211 degrees. Outside temp was 55 degrees. The plan is to replace the thermostat and check front of radiator for blockage. I might add, when a bought the Vette in Jan. I had the coolant flushed and it was nasty brown. Also, I checked the main fan and it comes on at the desired 176 degrees. This Vette is a Z51 with a stage 2 hyperchip. Sounds like the appropiate approach to me. Any other ideas?
Thanks, JW

 

Oil temps are always hotter then coolant, oil temps sound ok.
Your cooant temp should only get to 230 while idling or slow speed traffic, not while going down the road. Make sure the air dam is in place & that the space between the radiator & condensor is clear of debris. The main fan shouldn't turn on that low b/c it'll run all the time. I have a ford fan switch on my 84 that turns the fan on at 210*. I believe the fan control for the 85s is in the programming.

 

The best thing you can do is change out the water pump. Go to a FLOWKOOLER or similar high flow pump. This will greatly reduce your temps.

If you change from stamped rockers to roller rockers, you will see your oil temp drop about 8-10 degrees.

 

A wp will only help so much, you need good airflow through the radiator. It is a heat exchanger anyways. Don't start throwing parts at it, do some checking first.

 

Id pull the radiator out take it out to the driveway with a high pressure water hose and start blasting all the little fins out youd be surprised how packed with tiny bits of leaves and pebbles they get. straighteneing the fins if bent can add up too. Hold it up to the light to ck progress.
It makes a night and day difference in running temps especially at idle/low speeds. Make sure your air dams etc are all in place too

 

I have an 85 and had cooling problem.If you have not taken the radiator out. Do it and you will find a LOT of leaves and other debris between the radiator and the cooling radiator for the aircondition.
Check that the spoiler is ok under the front bumper. Having done that flush the cooling system and put antiifrost liquid in . That is good for the pump and the cooling. Put in Waterwetter. This softens the cooling liquid so that you are sure there are no bubles sticking to the metal surface in the heads and block. It decreases the temp with some degrees.
What you MUST not do is to use a high pressure water hose torinse the radiator because the radiator is not the common system. It has extremely thin aluminium flanges instead of the usual holes and they will be destroyed and bend in so that the air cannot go through the radiator!!!!!!!!!!! So if somebody has done that with high pressure water you will have a job bending thousends of those flanges back to their original angles.
If you get the dirt away, fushed the cooling system and put in the waterwetter and checked the radiator so the these small flanges ensures air throughput then the car should be cool enough(if a stock engine or moderatly increased power)

 

Just replace radiator. Its time.
I have an 84 and had same issues. I replaced it and now mine runs under 200 on coolant all the time. Sometimes I drive the car and the fans never come on at all.
You should replace it. Been in there almost 30 years.
It only has 1 core in it. You should get an all aluminum 2 core radiator and it will work fine.

Kevin

 

Seriously? This is your recommendation for above normal temps?
Cmon John you've been around long enough to start from the basics.

Like did you check the gap between the rad and A/C condenser?

 

Thanks for all the suggestions. I have one more. My normal coolant temp was 175. All of a sudden it jumps to 220. Only change other than warmer air temp was having the AC charged. Any connection?

 

I've never seen or heard of an early C4 with normal cooling temperatures running at 175. The majority of them including mine has always been about 198 to 228. The fan comes on at 228 and cools it down to about 200. It just seems to be where L98's run at. What was your secret to such a low temperature setting?

 

Here's the radiator out of my 85. Cleaned it up real good . Now on the road, my temp goes to 200 and then retreats to around 185 -195 and stays there unless I stop.