scottermis

Car has 30k original miles, flushed radiator, cleaned out the area between the condensor (was really anyting but a few leaves), hoses are all good or seem to be. Car is cool as long as your not sitting in traffic then it starts to climb pretty steady, i wondered if it could be the thermostat? I ordered a new AC delco 180 just in case. Thanks for any help anyone can give me!

KARR

Same thing happened to mine. What I found out was that the electric fans on mine were turning "on" at 220 degrees. The problem is that the car would start overheating at 230 degrees. This is apparently a known problem on the LT1.

I ordered this kit, and problem was solved.

http://www.parts123.com/parts123/yb....~Z5Z5Z50000050

RollaMo-LT4

What do you consider overheating?
I know, sounds like a dumb question. But since your a new member, I'll assume your new to the C4 also.

First thing, tell us the temp that is displayed on the digital temp gauge.

Normal Temps for an LT1 as displayed by the digital temp gauge:
Moving at any speed above 30mph = 195°F - 200°F
Sitting still for any length of time = 217°F - 235°F

MarkBychowski

What temps are you seeing? 230 on an LT1 or LT4 in stop and go traffic is correct. Seems insane, but that's how they're designed.

scottermis

Sitting in traffic at a light i noticed it was around 230 but the temp here is about 40-50 degrees. If it runs that hot this time of year when it gets to be 105 outside i can imagine i will have problems. Yes i am new to the C4 it is my first one. I picked it up from a one owner with
28k miles and had all the fluids changed and the radiator flushed. I was thinking it may be the 17 year old thermostat. The hoses are original and still look brand new.

RollaMo-LT4

No, it is NOT the thermostat!

The reason they run at 220 - 235 while sitting still is because there is no airflow moving across the radiator (unless the electric cooling fans are running).
In a factory late model C4 this does not happen until approx. 228°F

If your cooling system is in good condition, you will see these same temps your describing no matter what the outside temps are.

Even in 100°+ temps, my '96 will idle all day @ 217°F - 235°F
Once moving again, the temps will stay in the 195°F - 200°F range.

Tip: If you don't like the factory temps, you can make modifications to lower them. Just do some searches.
Another easy thing is to just turn on the A/C, as this will also force the cooling fans to come on.
Sounds crazy, but the C4 is one car that will run slightly cooler with the A/C running.

Kmcoldcars

It sounds as if you need to read your owners manual. If you do not have one you should go buy one. Also, if you do not want to pay your mechanic lots of money to do simple things on your Corvette, you should buy the 2 volume red cover set of the factory service manuals. They will help you diagnose and repair many ailments your C4 will develop.

sailorsteve

astepup

I too with this, however (and this may just be me) it seems these FSM's were written BY mechanics FOR mechanics. I'm slowly learning as I go through it trying to get a handle on various components and what they do so I "might" have an idea what to look for when a problem develops. Even one repair you can do yourself will most likely cover the cost of the FSM's. My "toy" before my '94 was a '70 Mailbu small block. Simple and straightforward to work on....the C4...not so much.

astepup said that

desertmike1

don't throw a bunch of money at an Non-issue!!

scottermis

Thank you everyone for your replies i REALLY appreciate it! I may go with the manual switch option if i want them to come on without turning on the ac. Look slike i have ALOT to learn but i am eager to do so i really enjoy this car. I have gone ahead and replaced all the weatherstrips and done a few small other maintenance things and really enjoy working on it. Thanks again!

scottermis

I also noticed when i fill up the car the filler tube sounds like a vacuum for about 5 seconds sucking in ALOT of air. Is there a tube or something blocked?

CStewTAMU

First, temp gauges in almost all cars are nothing more than glorified idiot lights. They don't give you a real time temp reading--they simple tell you "hot" or "not too hot". For example, if a car has 5 hashes on the analog temp gauge, the hash in the middle may represent any temp between 180-230 degrees. So even though the temp gauge needle settles on the middle hash mark and isn't moving much, the temps are indeed swinging back and forth. It's VERY not linear. The C4 vette's temp gauge isn't linear either, but it's closer to being linear than other gauges as it's normal for the needle on the gauage to move back and forth depending on driving conditions. Most people aren't used to this and freak out when driving a c4 vette for the first time.

You should know that the LT1 was designed to run hotter than most cars for emissions purposes.

If you're sitting in traffic and it gets up to 230 degrees, it should cool down pretty quick once you get up to highway speeds for several consecutive minutes.

One thing I would check that many people don't mention on here is the radiator itself. Over time, corrosion, dirt, rust, etc. finds its way into the cooling system. I removed the radiator from my 94 (since sold) and took it to a radiator shop. They removed the side tank on one end of the radiator and had a flat tool pushed through each side to side flat tubes. Half the bottom ones were clogged with gunk. It was no wonder my car was getting hot. It was if my radiator was only 6 inches tall as the bottom half of the tubs weren't passing any coolant.

Also, I should point out one thing:

You have 2 temp sensors. The on that gives info to the digital gauge (near the water pump if I remember correctly) and one that gives info to the analog gauge (located lower in the block if I remember correctly). These two readings will be different. Since the LT1 uses reverse cooling, the cooled coolant coming fresh out of the radiator passes by the digital sensor before it passes by the analog one. So there may be a few degrees of difference with the digital reading usually being a little lower once the car is warmed up.


Anyway, hope that helps.

pmihaltian

Hey Dave Perry, you should take a minute and fill out your user profile. There are many guys here who can benefit from your comprehensive C4 knowledge and your NCRS Master Judge experience.

P.

scottermis

There are alot of helpful people with great advice on these forums. I REALLY appreciate all of the input and i did order a manual switch for my fans. Driving it today in 40 degree weather it runs around 194 pretty constant and in town it runs around 210. Very good advice and thank you all again!!!

Y-ME

If you get a Hypertech power programmer you just program the car to turn the fans on at a lower temp rather than wiring up a switch you have to remember to turn on.

scottermis

Which Hypertech programmer would you recommend? I use similiar programmers on my motorcycles but i have never done a car with one.

Y-ME

There's more than one? How many does Hypertech make for one car?