95 coupe overheating

[sjr1118]

Hi Everyone. I just purchased a 95 coupe. Noticed the coolant temp rising quickly in stop and go traffic, such as waiting for a long light or a funeral to pass. Goes from about 190 to over230. If I turn on the a/c, which I think turns on the cooling fan, temp drops back down to normal range. I'm concerned because we have not even had warm weather yet. Any thoughts?

[92RAGTOP]

The first things to look at would be debris like plastic bags leaves etc... in front of the radiator those C4s scoop them up. The second would be the thermostat. If it has a lot of miles it could be the water pump but that's kind of a long shot unless it's dripping anti-freeze already (If it is the water pump change your Opti-Spark at the same time). The radiator could be restricted internally with calcium, if that's the case i'd just replace the radiator instead of trying to clean it.
I fought an overheating problem once on my 90 I did all the normal checks and it turned out to be a partially clogged catalytic converter. My EGR valve went bad (I don't think a 95 has an EGR valve but that doesn't mean your cats not bad) which sent unburnt gases to the Pre Cats, the Pre Cats desintergrated and got pushed into the Main Cat and partially clogged it. I had a loss of power at high speed and overheating in bumper to bumper traffic.
There is a kit that Ecklers, Mid-America sells etc... that will allow you to put a additional thermostat into the block that will activate a relay that will turn on your AC fan. This kit is suppose to remedy this problem. WRONG!!! DO NOT INSTALL THIS!!! My 92 (not 90) had this kit on it already from the previous owner. It does 2 things tries to hide an overheating problem and sends an unwanted voltage to the ECU (COMPUTER $1200) and destroys it. And if anyone doesn't believe that give Slapshot a call at Bryners he diagnosed the ECU problem removed and was 100% correct.

[DanS711]

Check to see if your primary fan is working. They have electric fans that cool the radiator. The first is set to come on around 213 and the second is set at around 236. If the primary fan is not coming on it will run up to that temp easily in traffic. When you turn on the AC it brings on both fans. If you want to check put on the AC and see if both fans are running. As Don said, make sure you check to see if your radiator is clear of leaves and other debris. I clean mine out 4 or 5 time a year, especially after driving in the fall with the leaves on the road. It's sort of a pain in the neck to check but if you kneel down in front of the air intake and look up in there you can see it pretty good.

DS

[sjr1118]

I will check both conditions. I have only had the vette since last saturday, but I like to solve problems even before they rear their ugly heads.

i'm still trying to learn how to best utilize the keyfob as well.:confused:

[PeteB]

I questioned the 230 degree temp when I got my '95. There is a lot of discussion on this in the Q&A tech help in the various mags.
Your primary fans are going to come on at about 215-220. (Actually it is running both fans at half speed due to a voltage split.) Between 225 and 230 your secondary fans (full voltage) will kick in.
If you are going above 230, there might be a problem, but I'd say that the system is working O.K. Still you might want to check with a Corvette specialist.
Don,
There is something that is different in the fan circuit before '95, and I'm not sure what it is. There is an extra harness that has to be installed with the auxilliary fan switch. I have installed a 160 degree thermostat and a 180 degree fan switch with no problems in the '95. On cool day I'm running about 175. On a hot day I get up to 190-195 at idle.

[Bob Weiss]

I think that these temps that you are reporting 225-230 degrees idling in traffic is Normal. I had an 89 and it would get up to 230+ idling in traffic then the fans would cyle and the temp would drop back down. I would turn the air on to run the fans sometimes.

I would:
1) check the radiator for obstructions (including bags and trash in front of the radiator).
2) Make sure both fans run as designed.
3) Have the cooling system flushed and the proper mixture of antifreeze (critical when you are running regularly over the boiling point) installed along with water wetter.
4) Check the system pressure/cap to make sure it is in tolerance.
5) Check radiator house to make sure they are in GOOD condition and not kinked or some funky aftermarket stuff.
6) Replace the temp sending unit as it could be reporting high.

Just a few ideas.

Bob Weiss

[C5pilot]

If the temp decreases when he turns on the a/c then I don't think it's being caused by an obstruction of any kind.

[92RAGTOP]

Joe he stated "If I turn on the a/c, which I think turns on the cooling fan, temp drops back down to normal range. "

[Bob Weiss]

Turning on the A/C causes both the fans to run thus reducing the temp. It might overcome a partial blockage.

Bob

[92RAGTOP]

Pete B. this is the kit my 92 had on it. According to Steve Spence at Bryners that's what took out the ECU. Sounds bizzare but he has not been wrong yet. All it does is turn on the AC fan which would not come on normally until the AC was turned on.

http://www.ecklers.com/images/vette/40415.jpg
1984-95 (C4) 185º Low Temperature Cooling Fan Kit
http://www.ecklers.com/assets/images/pdf_Instruction.jpg (http://www.ecklers.com/assets/pdf/40415.pdf?) Corvette Cooling Fan Low Temperature Kit, 185º, 1984-1995

Lowers Engine Coolant Temperature
Maximizes Engine PerformanceThe stock C4 Corvette cooling system runs inherently hot. GMP has the solution to this annoying problem. GMP offers a electric cooling fan switch, The switch will turn on the main fan, auxiliary fan or both at a lower temperature. Lower coolant tempeartures will maximize engine performance and reduce engine wear. Each kit comes complete with switch, harness, hardware and instruction sheet for easy installation.

P/N 40414 & 40415 switches are recommended for highly modified cooling systems and/or off-road racing only.

This switch (P/N 40415) turns your electric fan on at 185 degrees +/- 5 degrees and automatically turns it off at 170 +/- 5 degrees.

[SLAPSHOT]

On your 95 are you reading the temp gauge with the pointer or the digital read out by using gauges button on dic? The needle will almost be to shaded 260 mark and you only be at 230-235 witch is normal. The digital reads out by the speedometer.

[Glennm27]

Since you have owned this car for only days, I would suggest you make an appointment at Bryner Chevrolet in Jenkintown and ask them to be sure Steve Spencer checks your car out for you.

Being new to you, I think it would be a good idea to have the car chekced out from head to toe by a top notch Corvette mechanic, which Mr Spencer certainly is.....

[sjr1118]

...With the people in this club and all of the help and advice you have provided. I intend to bring the car to Bryner and have it checked out. You guys are really friendly and I plan on joining the club, if you will have me, so I can meet some of you in person.

Steve

[Glennm27]

...With the people in this club and all of the help and advice you have provided. I intend to bring the car to Bryner and have it checked out. You guys are really friendly and I plan on joining the club, if you will have me, so I can meet some of you in person.

Steve

And why not? Sure come check out the club. We love having new members.........

Our next General Membership meeting is April 12 ( I believe) :o

Our season opener Cruise Night at Pep Boys in Warminster is April 21st. That's a nice informal way to meet many of the members.......

[carboman]

...With the people in this club and all of the help and advice you have provided. I intend to bring the car to Bryner and have it checked out. You guys are really friendly and I plan on joining the club, if you will have me, so I can meet some of you in person.

Steve

Pay your dues and you're in. The advise is free. FYI, you get a disount on parts and servcie at Bryner if you're a memeber.

Once we get to know you we'll start busting on you.

[C5pilot]

Joe he stated "If I turn on the a/c, which I think turns on the cooling fan, temp drops back down to normal range. "

I know. If there is a blockage, turning the fans on will do little. Since turning the fan on with the a/c brings the temp down, it says the radiator and fluid are adequate. The question is why aren't the fans cooling it down on their own. But Steve already said the temps seem normal. A flush is probably a good idea either way.

[jonmentzer]

just to add to whats already been said. when diagnosing a problem you should go through all the proper checks first, before replacing any parts. its the simple things that will get you.

[sjr1118]

Well, Ladies and Gentlemen who responded to my question...Perhaps I jumped the gun a bit.
I started it up cold this afternoon and let it idle while watching both the digital temp. readout and the fans at the same time (pretty boring 20 minutes or so)
Anyway....both fans came on at 228 and the temp. quickly began to drop. Both fans turned off at 216.

So I guess the car is going to run between 216 and 228. Does that sound right?

I think I over-reacted because the temp. guage (not the digital) was very close to the hash marks on the dial. I just did not want to blow up my new vette before it was mine for at least a week.

Now my issue is to figure out the best way to secure both door panels which are loose at the top. I don't mind tinkering a bit, but its getting pretty close to perfect Harley riding weather.

Hope to meet you guys soon at a meeting

Steve

[PeteB]

Yes, I had the same problem. A previous owner had a actually added a screw thru the door panel to try to keep it from pulling away. Didn't work.
There is a remedy that is the best that I've found. It involves removing the door panel and installing a small angle to give the panel something to catch.
The flange that catches the door panel is too low near the rear of the door and does not hold.
I'll try to find the article that explained this fix in Corvette Fever and scan it for you.