94FormulaV8

I just bought the car tonight, and the Temperature Gauge keeps going up and down a lot like it is overheating.

When I drive it goes to around 210, then when I am at a stop it goes way over 210, then once I start driving again it goes back down again really quick.

The guy drove it to my apartment (over 3 hour drive) and it didnt overheat. I didnt have a car so he drove it over 3 hours for me to see it.

The low coolant light is on too, but it looks full.

Should I still drive it?

6SpdLT1Z

When the car is stopped you dont have air flow to the radiator so that is why the engine will warm up.

Your coolant level sensor probably shorted out, easy to replace.

Shoebox has a GREAT site, and you will find all the answers to your questions on there.

4th Gen LT1 F-body Tech Articles

94FormulaV8

Thank you VERY much for that link! It is going to really help me out!

Because this is my first LT1.

6SpdLT1Z

We've all been there, I'm on my 4th.

wjdaggett

Could be trapped air bubbles I know I had the same problem when I first got my 93 z28. Took many burpings to finally get the thermostat to read steady and not fluctuate like mad.

Injuneer

The low coolant light being on when the radiator is full is a common problem - you are checking the level in the fill neck of the radiator, and it is full to the very top, correct?

The coolant level switch cruds up. Sometimes it can be cleaned, but often it's an internal leak in the switch and the coolant has corroded the circuit board. In that case, it requires replacement.

Define "it goes way over 210". What temperature does it go to? The first fan (or both fans on low - depends whether you have an "early" of a "late" model 94) goes on at 226*F, the second fan (or both on high speed) at 235*F.

Since your car is new to you, I would totally flush the cooling system and the heater core, and check to insure the engine has the correct LT1 thermostat. You can't use a generic t'stat for a Gen 1 SBC.

Since you already have the link to Shoebox's site, be sure to make maximum use of the numerous tech articles related to the cooling system. The LT1's unique "reverse flow" cooling system (at least the way they set it up in the F-Body cars) can be problematic, but when it works correctly, it's allowing then engine to run maximum spark advance, and make maximum power.

trillmvtic

I have a 94 Z28 , temperature gauge is having the problem , I drive it goes down , come to a stop, it rises . I need help diagnosing the problem . Replaced thermostat , water pump , & flushed the radiator.

moparman

The answer is in the preceding posts. It's perfectly normal for the LT1 to heat up when at a stop and to cool down when moving.

Injuneer

How hot (in degrees) does it get to when it "rises"?