Good morning everyone. This past Friday night I took my 94 on its 1st car cruise in Coopersville for the Del Shannon car cruise. Had to pull out part way - my temp. gauge registered almost 260 degrees , I was in the hash marked area. Other than checking the thermostat is there any thing else I should look into? I can't beleive the LT1 should run this hot normally or am I paranoid?
Thanks in advance

A couple of questions then a few things to look into:

- did this happen while in stop/go traffic or on the freeway? Does it heat up in traffic and then cool down above about 40mph?
- how far into the trip did it happen?
- Can you hear the fans running?

1. Trash/debris in front of the radiator - take a flashlight and look into the radiator shroud from the passenger side
2. Old radiator - could be clogged inside or between the fins (either way should replace it)
3. Run car at idle, what temp do fans kick in (and/or turn on AC - does second fan come on?)
4. New thermostat
5. Are you losing coolant? Is there a bubbling noise in the overflow tank after you switch the car off?

Yea, what Andy said.
Debrie inbetween the condenser and radiator happens a lot.

You will heat up crusing under 35mph. But the fans should come on. It varies a little by year but the primary fan should kick on at 226, secondary at 235.

To check operation, just idle the car and watch the fans, they should come on at those temps.

If your a/c is working (blowing cold), turn on the a/c at any engine temp and see id the fan(s) come on.

Both fan relays are on the drivers side radiator shroud mounted side by side. The relays are engaged by grounding them (by the ECM).
Check the wiring connector to them and pull the relays to check their connection.

The circuit to both relays - the pink/black wire should be hot (key on). The grounding wires from the ECM are blue/white on one and green/white on the other.

Also, at the fans, you should see 12v on the black/red or black/pink wire at the fan (a/c on, engine idiling) may be one or both fans with the a/c on.

Yoou can also put in a manual switch to turn the fans on when ever you want but you have to have everything functioning correctly first.

Make sure there's no air in the cooling system - once it's up to temp, put a rag around the bleeder screw on the t-stat housing and crack it upen - close when you get a solid stream of coolant.

A couple of questions then a few things to look into:

- did this happen while in stop/go traffic or on the freeway? Does it heat up in traffic and then cool down above about 40mph?
- how far into the trip did it happen?
- Can you hear the fans running?

1. Trash/debris in front of the radiator - take a flashlight and look into the radiator shroud from the passenger side
2. Old radiator - could be clogged inside or between the fins (either way should replace it)
3. Run car at idle, what temp do fans kick in (and/or turn on AC - does second fan come on?)
4. New thermostat
5. Are you losing coolant? Is there a bubbling noise in the overflow tank after you switch the car off?

Andy-
1. It happens in stop and go traffic / low cruising
speed.
2. If I get it above 35-40 yes, it cools down.
3. It happened half way through the cruise- cruise was
approx. 10 miles- take or give a few miles. In and
around Coopersville.
4. Can't hear the fans kick on until in the hash marked
area of the gauge. What's that 230 degrees or more?
5. Will go out and look now around radiator for debris.
6, I am assuming it is original radiator- car has 61,000 miles on it.
7. Had the Vette in the driveway Sat. and turned it on ,
left it idling to see what happens- approx. 3 min.
later I have a temp. gauge that is almost pegged.Did
not hear fans kick on. Bad relay? Switch?
8. Have purchased a new thermostat and will put that
in. No coolant is being lost or seeen on the garage
floor or ground. No bubbling sound

thanks for the help.

Quote:

Turn on the AC and see if the fans come on.

Bill H. - You mention using the digital gauges on the dash instead of the analog- I beter get the owners manual out. am I assuming one of the switches ( Eng./ Met. ) and the others allow me to do this. Yes, I am very new to this. thanks

Quote:

Everybody's new at some point, no biggie.

Yea, the switches you mentioned, push the "gauges" button, and cycle it until you get "coolant temp".

Then do the checks again, hood up & watch the fans, report back.

I leave the coolant temp on all the time.

thanks, Bill, will be checking it out tonight or tomorrow. Vette is at a shop having strripes(Grand Sport in red) put on to it. Watched the temp. gauge out to the shop and it ran normal all the way out there- approx. a half hr. from my house.

Our cars are bottom feeders as far as getting air to the rad goes. I'm always amazed at how well it picks up leaves and crap from the ground. You have to clean them out every year.