Im no mechanic, and I have had my 95 coup for 3 weeks. I have only driven the vette on short commuting trips sofar until today. I always thought it ran a little warm, well past the midpoint in the temp gauge, but being new to the car I assumed maybe that was normal.

Today, I drove my daughter around a good bit and went through a restaurant drive-thru where we sat for a while in line. The tem gauge began to approach the 260 line and I started to get pretty nervous. About that time our order was up and we got back on the road. I cranked on the heat full blast and the vette began to cool, but not significantly. I pulled over and popped the hood and made note that the radiator fan was not turning.

Not being a mechanic, shouldn't the fan be running? I only saw one fan that was approx 10" in diameter directly behind the radiator. Also, could this be a thermostat issue?

Thanks for the help
Steve

 

At 260*F the cooling fans should definitely be running. Get this repaired ASAP.

Be well,

SJW

 

........ Also I would look at the digital gauge. Scroll through the GAUGES button on the dash until the coolant temp. shows up. Normal temps in a LT1 run between 190-210 with it getting in to the 220-230 range in stop & go traffic.....

 

Against conventional wisdom turn on the AC if it goes hot again. The fans should energize as well as the compressor clutch. The fan turns on at 235* at the drive thru. If not you have a problem. If so you might change the thermostat. Do you have full coolant and water in there? A bouncing baby 3 week old should have ALL fluids checked or changed.

There are volumes on that subject discussed ad-nauseum here. Do the AC on check to see the fans function first. Then auto on at 235* using the digital temp readout using Gauges button. If no fans get it fixed now. You run an aluminum head hot a few times and you'll be in a world of hurt.

Let us know what happens. Many have fought this battle.

 

Thank you, I will run these tests. I agree, the first thing i did the day after i bought it was take it to a mechanic i trust and had him go over the whole car. Everything was good except for the transmission fluid was dark. I had a transmission service done. I'll check coolant levels again, but 3 weeks ago it was fine and no puddles in the garage where i park her.

Will let ya know what i find out.

 

Definitely too hot.. check the area under the shroud and see if it is full of junk. Must be the fan. I think if you turn on the air, your fans should come on... good luck...

 

same on my LT4 as well

 

Read THIS thread.

The digital guage receives it's reading from the CTS in the water pump.

The analog guage receives it's reading from a sender in the cylinder head.

I usually only look at the digital guage for the correct temp and the analog usually reads higher.

 

You may trust him (and he may be a good mechanic) but does he know Corvettes and is he familiar with their cooling system? These cars hold close to 18 quarts of coolant, and with the upper expansion tank there is ample opportunity for trapped air in the system. Check you owners manual for the procedure to purge the air from the cooling system.

Of course none of this addresses the problem of the fans not coming on, but it should be done anyway.

 

Ok, i digested all this info and printed it out. Pulled the vette out of the garage and let her idle. After about a minute i turned on the A/C - both fans came on. I turned the A/C off and let it idle.

I watched the digital gauge and the analog. The analog gauge got into the hash marks and approached 260 deg. This is what happened this morning. However, i was watching the digital too and it was reading 226. When the digital gauge hit 227, the interior lights dimmed for a split second. I assumed the fans had just cut on. I looked, and sure enough, both fans were running. The temp dropped to 216 rapidly.

From reading RRT Vette's FAQ, my LT1 did exactly what it was supposed to do. The analog gauge is WAY off and made me panic.

Im very glad that I dont have a cooling issue, but it is very irritating that the analog gauge will get into "redline" and be so far from acurate. I wonder how many people have paniced like i did when they saw that? Maybe every C4 owner since 1984?

I love my car, and am very passionate about it, have wanted a C4 since i first saw the comercials on TV for them back in the early 80's. But that analog gauge down there crying wolf is disturbing.

How will i know if im really overheating? Will a warning light come on?

Thank you very much for your input everyone.

 

No, no warning light will ever warn you in time. Sometimes, you just have to do preventive maintenance, "hear" your car, watch the gauges, etc. I drive with my digital temp gauge always displayed first. Other things are a bit secondary, to me.

So, for instance, it's not a bad idea to do the "preventive maint." of changing your cooling system fluid. I'm going to assume that you live in an area where there is winter, and that you may not be driving it much over the next few months. All the more reason to do the flush and fill.

And, it wouldn't be a bad idea, depending on how many miles are on your car to look carefully betw. the condensor and the radiator to see if there's any "junk". These cars are known for acting like vacuum cleaners and sucking up leaves and dirt in betw. the two. You may have to remove the condersor and wash out the leaves and junk. Preventive, or prescription.

You may also want to look at Jet-Jock's excellent post with pics this year on his new OEM replacement radiator compared to his dirty original radiator; SJW also did the same thing.

Hope this helps you.

 

I had what sounds like the same problem on my 94 lt1 coupe. On my car I bought the GM service manuals to get the info. The sensor in the water pump (screws in the front) controls the signal to the computer which turns on the fans. This also controls a few other things like how it runs. The sensor in the right side cylinder head controls the gauge only. My car would run hot and the fan would not come on. Then it started to run bad. I changed the sensor in the head by mistake first. Then I bought and read the service manual. I changed the sensor in the waterpump and then the car ran great. The fan on the drivers side comes on at 227 degrees just like it's supposed to.Until you get it fixed turn on the a/c to drive it. Get it fixed SOON so you don't cook the motor.
Good luck and I hope this was some help.
Bill

 

Your car is running exactly right! Now if you want it to run cooler you will have to do a few things to it.

Change the coolant and thermostat. I vote Hypertech 180*. Put in 2 bottles of Redline Water Wetter. Clean out any debris in front of the condensor and radiator. Air is preferred over water for this because of the distributor (OPTISPARK). Don't hose her down!

I had my PCM reprogrammed to turn the fan on low speed at 208* You may want to look into this with Alvin at PCMFORLESS. The last resort is a BE COOL or DEWITTS radiator. Chevy put the smallest, lightest radiator in there that would barely keep up.

Or don't do anything and enjoy your new street legal race car that runs a little on the hot side, as designed.

 

Heading down to inspect the area between the condensor and radiator.

Fueler, if i change the sensor in the right side cylinder head that controls the gauge, will the analog gauge be more acurate?

Tlong, is there a benefit to the cooler thermostat and the programming? Does the engine perform better at the cooler operating temperatures? BTW, i am going to get the PCMFORLESS chip anyway, i like the performance/mileage/shifting that you get out of it.

 

There is no chip for the ECM in the 95 model. The ecm has to be reprogrammed to change settings. Other option is a Hypertech Power programer, which has some limited benefits. I have one and if I had not bought it cheaply it would not have been worth it. I would recommend change the sender in the right head. Stock T/Stat is 180* and the debate about best temp stat will rage on forever so I won't even try to get into that. Factory fan settings are main on at 227* and aux on at 236*. Lastly, there is a bleeder screw on the top of the T/stat housing (passenger side) that must be used to bleed the air out of the motor.
Do it once or twice engine running, then once more after reaching op temp and t/stat open. Wrap a rag around the bleeder so A/F does not drip down onto the optispark. Hope this helps. And Welcome to the Fun and Crazy Corvette world, I love my 95 like you will (or do) yours.

 

Wow, I thought the stock themostat was 200. I've got a 94 LT-1 and it runs right at 200 in the summer with the a/c on and both fans blowing. Now, it's fall and it runs about 208 on the road and about 214 in town. Gets hotter real fast in slow traffic.

I don't like that. I'd sure like it to stay under 200. I've made SURE the space between the condenser and the radiator is clean.

If I put a 180 thermostat in it, will that make it run a little cooler? What's the best program to reprogram and watch what is going on with all the sensors?

 

Good Question I ran in to the sam problem.!!

 

The 180* thermostat is stock and has an edge over the 160* in the polls. The PCM (brain) is reprogrammed. If you are already sending it to Bryan and Alvin include the lower fan settings. I think you have 2 speed fans and won't even hear them on. That should keep it much cooler.

 

I checked out the "tween" area for trash... checked the entire engine every nook and cranny for that matter. No trash here

Thanks alot for the tip on that, I'll keep a watch on it.

I'll be sure to include a mention to pcmforless about cutting the fans on sooner, if they dont do that as a standard already.

I'm with Arkybill... if its all the same, I would rather the temp stay under 200. That way the analog gauge isnt making me panic

 

You will know when the engine starts to overheat. There will be a sluggish/missing type problem when the temps get too high. I would turn the engine off if the temp ever got to 240* per digital guage.