LT1 Coolant Temperature - What is normal?
Thread Starter
Heel & Toe
Joined: Jul 2012
Posts: 22
Likes: 0
LT1 Coolant Temperature - What is normal?
I drive a 1994 LT1 every day (unless it snows). It never overheats, but the coolant temperature varies quite a bit. On a cool day and open road it stays around 190 degrees which is great. If it is either warm out or a traffic jam or the air conditioning is on high or multiple thereof, it seems to depend on the wind direction and the moon phase what the coolant temperature will be. On the digital display I read 225 quite often and sometimes up to 235. Is that within the normal range for a 20-year old LT1? Or do I have an air bubble somewhere?
My Mercedes always stays at the exact same coolant temperature of 180, no matter how I drive, even if the car is on fire.
Please don't respond telling me the LT1 is crap. Most Saturn drivers would be happy to have an engine :-).
Thanks for any feedback!
Andy
My Mercedes always stays at the exact same coolant temperature of 180, no matter how I drive, even if the car is on fire.
Please don't respond telling me the LT1 is crap. Most Saturn drivers would be happy to have an engine :-).
Thanks for any feedback!
Andy
Race Director
Joined: Oct 2005
Posts: 11,771
Likes: 177
From: Rolla Missouri
2021 C4 of the Year - Unmodified Finalist
St. Jude Donor '10 thru '25
Since the Corvette uses electric fans, you will have no airflow moving across the radiator unless you are moving, or the fans are running.
So, what is normal as it left the factory.
Sitting still with engine running (at a stop light or heavy traffic)
217°F - 235°F
The cooling fans don't come on until approx. 228°F (depending on year)
You can force them on, by turning on the A/C
The C4 is one car that will actually run cooling with the A/C running.
Moving at any speed over approx. 35mph
190°F - 200°F
Those 217°F - 235°F temps you see while in traffic are perfectly normal, even though quite a few people don't like to see them.
That is the way the car ran when it left the factory.
With a modern cooling system in good working condition (proper coolant mix and pressure), the boiling point is approx. 260°F.
So, no damage is being done at 230°F.
So, what is normal as it left the factory.
Sitting still with engine running (at a stop light or heavy traffic)
217°F - 235°F
The cooling fans don't come on until approx. 228°F (depending on year)
You can force them on, by turning on the A/C
The C4 is one car that will actually run cooling with the A/C running.
Moving at any speed over approx. 35mph
190°F - 200°F
Those 217°F - 235°F temps you see while in traffic are perfectly normal, even though quite a few people don't like to see them.
That is the way the car ran when it left the factory.
With a modern cooling system in good working condition (proper coolant mix and pressure), the boiling point is approx. 260°F.
So, no damage is being done at 230°F.
Melting Slicks
Joined: May 2007
Posts: 2,075
Likes: 109
From: Longmont Co
The LT1 is a great engine. Not sure where you heard otherwise. Your temp ranges seem about right. Check that your fans do come on about 228, and check the front of the radiator for debris, but I don't think you have anything to worry about.
Instructor
Joined: Nov 2009
Posts: 164
Likes: 2
From: Spring Texas
Four years ago when I purchased my 1995 LT-1, It ran 225 in traffic and up from that idling. The antifreeze had been mixed Dexcool and Ethylene Glycol and was a sludge at engine temp. I asked the local radiator shop to flush it and they recommended a replacement which I purchased from recycle Corvettes in SLC, Utah ($100 + S&H). I flushed the engine thoroughly with hot water, with the knock detectors removed. Replaced the water pump with an AC Delco and thermostat (190)and the digital temp sensor and new heater core and hoses. I filled the system with 50-50% Ethylene Glycol and burped it.
In Houston traffic in the summer at 25 mph or up it runs at 200 degrees. Idling in heavy traffic it occasionally gets to 216 degrees on digital temp readout. I am prepared to replace the WP with an electric one if heavy traffic produced higher than 220 degrees, but haven't seen that yet. Those summer temps are with AC on, also. I have performed the same operation on 3 different LT-1's, post 92 with the same results. No substitute for a good cooling system. Good Luck.
In Houston traffic in the summer at 25 mph or up it runs at 200 degrees. Idling in heavy traffic it occasionally gets to 216 degrees on digital temp readout. I am prepared to replace the WP with an electric one if heavy traffic produced higher than 220 degrees, but haven't seen that yet. Those summer temps are with AC on, also. I have performed the same operation on 3 different LT-1's, post 92 with the same results. No substitute for a good cooling system. Good Luck.
Instructor
Joined: Nov 2009
Posts: 164
Likes: 2
From: Spring Texas
Some additional data on operating temperature. The PO had one cooling fan to come on at 180 degrees (driver's side). I left it there, but installed a double pole, double, center off on the dash where either or booth fans can be activated manually. I did this on my 1986, purchased new. It always had trouble in Houston stop and crawl traffic. I have not needed that cooling capacity yet. Control for fans is simple. Supply ground to one or both relays in parallel with the ECM computer.
