We are new to Corvettes--just got our 1990 Coupe--and we have several main concerns--hope you can help us out!
We don't know what is "normal" for the 'vette, but when driving in stop and go traffic the engine seems to get really hot (weather is around 70 degrees, and very humid here). Is this normal? When we get out on the highway it cools down. What's going to happen when it's 90 degree weather? Is there anything we should do to modify the cooling system (it has an engine oil cooler already).
Thanks!
Mike and Linda

 

Hello Mike and Linda...welcome...you can get a temp sensor that will kick your fan on sooner or you can put a manuel toggle on to flip the fan on...also make sure there is no trash between your radiator and the condensor...it gets LOADED. Make sure there is ample water and no air in radiator, and that your stat is working properly..... Enjoy your new short

 

How hot is it getting? If it is going above 240 F that is getting pretty hot. I think average ranges are about 180 - 220 F or so.
Depending on what is happening it could be many things. This last year, my car was getting up into the 255 range in city driving, but would cool off on the highway. It turned out that the area between the radiator and AC condensor was filled with debris, hence no air was getting through at slow speeds. It looked like a lint trap! Could be something like this.



[Modified by C4-Wolf, 8:45 AM 4/2/2002]

 

Linda and Mike,

Welcome to the family :cheers: .

First of what do you mean my "really hot". Corvettes do run a bit warm but to some people 190 degrees is hot, but temps into the 230s are not unusual.

Some things you can check are:

1) Be sure your radiator is clean (see Tech Tips for procedures). Since it cools down once you get moving this is a likely culprit. The air intake is so low on these cars that it tends to act like a vaccum cleaner. Check out this posting http://forums.corvetteforum.com/zerothread?id=265835 .

2) Be sure you have sufficient coolant and that it has a sufficient blend of anti-freeze (50-50 is usually recommended, but others will argue other blends).

3) You can try stuff called Water Wetter, it helps heat transfer. You can get it at most auto parts stores.

4) Turn on your air conditioner, even if its cool outside. It kicks on the fans at lower temperatures.

5) You didn't mention how well serviced your car was. At 12 years old, I would expect that a good cooling system flush would be in order. Gunk builds up on the best cared for engines over time.

Have fun.

 

Thanks for all your very prompt help! We'll check everything you mentioned. We're going to have a lot of questions (just like first time "parents")! Hope y'all don't mind.
Mike and Linda

 

I got a hypertech chip and 160 deg thermostat. Now I never see over 190. I know theres lots of controversy over being a real performance solution, esp givin the price (I got mine for free) but, the engine running cooler is the best feature of it. Running up to 225 before the fans turning on just bothered me. It may be "normal" and ok for the motor, but everything else is getting cooked under there, there was heat fumes coming off the hood, a lot of the plastic pieces (electrical connections and such) were getting all brittle... I'm much happier the way it runs now. One side effect was though, I burned up my fan motor. But it was only about a 20 min job and 35 bux to replace it. I'd rather replace those then cook everything else.

Welcome and enjoy the forum :cheers:

Jim-K

 

well you should do what John Row said

Clean the radiator and flush it.
Get a 160 thermostat, and then contact Marcho Polo (on this forum in the ECM section) and see if he'll burn you a new chip for your computer so that your fans will come on earlier. DO NOT buy a hypertech chip that you see in these vette magazines.

vettes were designed to run hot for emissions purposes, and make sure youre running Mobil 1 synthetic oil because it can take such high temps easily

 

Welcome Mike and Linda.

Being a 90 I would do two things real quick. As other have said, clean between the radiator and condensor...it sits right in front (low) of the radiator. At first I thought it was an oil cooler (but LT1's don't have an oil cooler). Mine wasn't too dirty but I cleaned it up anyway.

Change the thermostat to 160. This is cheap, about $20. Now, you would logically think that if the engine is getting hot, the stock 180 thermostat is already opening at 180, so what difference will that make? Here's the kick...your 90 thermostat may be malfunctioning due to age and might be stuck or opening really late..like 200-220. Put in a new 160...you need to anyway...even if you go with a chip to turn the fans on sooner.

By doing just those two things (wait on the chip), you may be pleasantly surprised...I was! Highway is 190-195...idling is about 190-213 (depending on the weather).

 

A few suggestions that may put your mind at ease about the gauge reading as well as verify the proper operation of your thermostat:

Starting with a cold engine, remove the radiator cap and start the engine. Have a good quality thermometer on hand that reads up to at least 212° F (100° C.). Keep an eye on the coolant and, when you get curious, slip the thermometer in the neck of the radiator and check the temperature.

As it approaches normal operating range, you will see the coolant start to churn, or flow around. Your thermostat has just opened up. Take another reading. I'll bet that the gauge on your dash will be around 200°. I'll also bet that the thermometer will read 180-190°. Mine shows about 175° with a new 195° thermostat. But the dash gauge will show 210°!

Remember, the gauge is showing the coolant temperature in the head - and it's actually a lot cooler in the radiator and water pump. Don't let a 225° gauge reading rattle you - it's normal. Of course, if your thermostat isn't working, or your fan doesn't come on over 230° or with the air conditioner, then you need to do some work.

Keep the coolant to a 50/50 mix. This is not only for anti-freeze protection. The ethlyene glycol also raises the boiling point of the water, as does the radiator pressure cap. We were in a parade last summer in 85-90° temperatures for an hour and a half - without moving one block! The dash gauge showed 230-245° as the fan would cycle, but I knew the overall coolant temp was a lot lower than that. We had no problems.

To summarize:
Have a pressure cap and make sure it works.
Maintain a 50/50 coolant mix.
Verify your thermostat is operating properly.
Check your coolant temp with a thermometer.
Check fan for correct operation
Keep a clean radiator - inside and out.

Do these things and you won't need to modify your system.

Happy cruising! :seeya
Rich