overheating lt1
Thread Starter
Intermediate
Joined: Aug 2023
Posts: 33
Likes: 1
overheating lt1
i recently bought a 1993 zf6 and 3 days after i brought it home it started over heated. I bought a thermostat that i have not installed yet. All coolant components of the car are from factory and the previous owner did not care for the car at all. This is my first time working on a American car and i see it more as a resto project that i rly want to be able to daily. any advise and tips are welcome
Last edited by c4bomb; Sep 12, 2023 at 12:21 PM. Reason: typo
Instructor
Joined: Sep 2022
Posts: 209
Likes: 81
From: Dalbo, Minnesota
After the car cools down check the radiator hoses and see if any are collapsed. If so replace the coolant reservoir cap.
200f is normal. Fans come on at 220f. Go by the digital readout not the gage.
replace thermostat. Read up on how to drill a hole in the thermostat and on how to bleed air out of the system.
200f is normal. Fans come on at 220f. Go by the digital readout not the gage.
replace thermostat. Read up on how to drill a hole in the thermostat and on how to bleed air out of the system.
Le Mans Master
Joined: Jul 2004
Posts: 6,234
Likes: 699
From: Clifton Park, NY ............Clearwater, FL ... 85 Original Owner
i recently bought a 1992 6zf and 3 days after i brought it home it started over heated. I bought a thermostat that i have not installed yet. All coolant components of the car are from factory and the previous owner did not care for the car at all. This is my first time working on a american car and i see it more as a resto project that i rly want to be able to daily. any advise and tips are welcome
Le Mans Master
Joined: Apr 2000
Posts: 5,713
Likes: 105
From: Manassas VA
Wait....... Could you answer a few questions first.
1. What is the temperature that it is overheating to? FWIW 230 or a little more is common (and normal) at idle or stop and go traffic.
2. Does it overheat all the time, only at idle, or only when driving at speed.?
FWIW there are lots of things it can be from low coolant, dirty radiator, bad t-stat, bad fans, bad relays, bad sensors, just to name some.
More info is needed.
Oh, and by the way, the LT1 t-stat is specific to that engine, (different design from SBC) and the FACTORY one is rated at 180 degrees F.
1. What is the temperature that it is overheating to? FWIW 230 or a little more is common (and normal) at idle or stop and go traffic.
2. Does it overheat all the time, only at idle, or only when driving at speed.?
FWIW there are lots of things it can be from low coolant, dirty radiator, bad t-stat, bad fans, bad relays, bad sensors, just to name some.
More info is needed.
Oh, and by the way, the LT1 t-stat is specific to that engine, (different design from SBC) and the FACTORY one is rated at 180 degrees F.
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Thread Starter
Intermediate
Joined: Aug 2023
Posts: 33
Likes: 1
Wait....... Could you answer a few questions first.
1. What is the temperature that it is overheating to? FWIW 230 or a little more is common (and normal) at idle or stop and go traffic.
2. Does it overheat all the time, only at idle, or only when driving at speed.?
FWIW there are lots of things it can be from low coolant, dirty radiator, bad t-stat, bad fans, bad relays, bad sensors, just to name some.
More info is needed.
Oh, and by the way, the LT1 t-stat is specific to that engine, (different design from SBC) and the FACTORY one is rated at 180 degrees F.
1. What is the temperature that it is overheating to? FWIW 230 or a little more is common (and normal) at idle or stop and go traffic.
2. Does it overheat all the time, only at idle, or only when driving at speed.?
FWIW there are lots of things it can be from low coolant, dirty radiator, bad t-stat, bad fans, bad relays, bad sensors, just to name some.
More info is needed.
Oh, and by the way, the LT1 t-stat is specific to that engine, (different design from SBC) and the FACTORY one is rated at 180 degrees F.
Le Mans Master
Joined: Oct 2004
Posts: 7,706
Likes: 486
From: Everett WA
C4 of Year Finalist (appearance mods) 2019
You might also consider replacing the radiator pressure cap.
As others have suggested ....... this is a very good read:https://www.corvetteforum.com/forums...peratures.html
As others have suggested ....... this is a very good read:https://www.corvetteforum.com/forums...peratures.html
Drifting
Joined: Nov 2018
Posts: 1,778
Likes: 652
From: USA
I feel doing a cooling system pressure test would be a good idea, just to make sure you don't have a bad head gasket(s) or cracked head(s)! 260°F is too hot IMHO, you won't get away with that too many times. Hope you get it figured out👍
Edit: Also, using a infrared laser pointer thermometer is great way to verify actual temperatures all over the engine, hoses and radiator!
Edit: Also, using a infrared laser pointer thermometer is great way to verify actual temperatures all over the engine, hoses and radiator!
Last edited by '78CorvetteS.A.; Aug 31, 2023 at 08:28 AM.
Le Mans Master
Joined: Apr 2000
Posts: 5,713
Likes: 105
From: Manassas VA
1. one time i took it to 260 then turned it off and heard it boil. It overheats all the time, at idle and while driving. im going to check if the rad is clogged and do a flush. the fans are turning on so ive ruled them out already. yea i ordered the t-stat on rock auto so i believe i should have gotten the correct one
ok, the next thing I would do is start it up, let the temperature come up to 200 or so, then start misting or lightly spray the radiator with water. If the temperature drops or stays steady, it is most likely a radiator problem. You could pull it and clean it , but IMO on a 31 year old radiator, I would replace it. It appears they are $125.00 for a standard replacement from rock auto, so about $150.00 all in.
Safety Car
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From: LeClaire Iowa
Melting Slicks
Joined: Feb 2003
Posts: 2,699
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From: Saskatoon Sask.
As I am always open to learning new CORRECT information, I would be interested in knowing how a dirty air filter would cause an engine to overheat. Keeping a clean air filter is a given but changing it would stop overheating???? That's a new one.
Thread Starter
Intermediate
Joined: Aug 2023
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Yea i was looking into getting one but before i buy one im going to get a block tester since im not leaking the coolant