c5 overheating, gets to 140.
Thread Starter
Intermediate
Joined: Jul 2008
Posts: 36
Likes: 0
c5 overheating, gets to 140.
My engine light chimed overheating when it hit the red. It gets hot 140 on the DIC at a light so I assume the sensor is ok. The fans will not turn on even with the air on, all the fuses are ok. How do I test the relay's simply ?
Thread Starter
Intermediate
Joined: Jul 2008
Posts: 36
Likes: 0
Sorry - 240, long day. The fans are kicking on. It gets to 250 now but drops when I roll. I'm gunna check to see if it will take coolant. Its been a hundred plus here in the mid west forever and a day.
Thread Starter
Intermediate
Joined: Jul 2008
Posts: 36
Likes: 0
[QUOTE=8VETTE7;1581405808]Really, 140 is hot???? Do you mean 240????
Did you check all 3 fuses? 14, 46 and 49??
Fuse 49 controls low speed fan operation for both fans and drivers side fan high speed operation. Fuses 14 and 48 control passenger side fan high speed operation.
Relays 43 and 45 are both SPST so you could swap then and see if there is a change. If relay 45 was bad then there would be no fans at low temp turn on (low speed fan operation) and when the AC was turned on. I really can't imagine more than one relay at a time failing but I guess anything is possible. Relay 44 is an SPDT relay so you need to find another SPDT relay to swap out. Bench testing relays is NOT simple unless you have the proper test gear.
Relays 44 and 45 are used in conjunction with 43 to operate the fans in high speed mode (turn on temp from the factory would be 235 degrees). Even if either or both of those were bad you would still have low speed operation.
I would physically check the fans themselves. I've seen plastic bags get sucked up and destroy fan motors and wiring.
Yean all fuses are good, the fans are on, i swore they weren't earlier but it is still gettin to 250 sitting on the side of the road.
Did you check all 3 fuses? 14, 46 and 49??
Fuse 49 controls low speed fan operation for both fans and drivers side fan high speed operation. Fuses 14 and 48 control passenger side fan high speed operation.
Relays 43 and 45 are both SPST so you could swap then and see if there is a change. If relay 45 was bad then there would be no fans at low temp turn on (low speed fan operation) and when the AC was turned on. I really can't imagine more than one relay at a time failing but I guess anything is possible. Relay 44 is an SPDT relay so you need to find another SPDT relay to swap out. Bench testing relays is NOT simple unless you have the proper test gear.
Relays 44 and 45 are used in conjunction with 43 to operate the fans in high speed mode (turn on temp from the factory would be 235 degrees). Even if either or both of those were bad you would still have low speed operation.
I would physically check the fans themselves. I've seen plastic bags get sucked up and destroy fan motors and wiring.
Yean all fuses are good, the fans are on, i swore they weren't earlier but it is still gettin to 250 sitting on the side of the road.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Thread Starter
Intermediate
Joined: Jul 2008
Posts: 36
Likes: 0
OK..... So the problem REALLY is that even with the fans running, the temp is reaching above 240??????
If that is REALLY the problem then I would start by checking to see how much trash you have sucked up into the radiator cavity under the car. Common issue is that since these cars are bottom breathers, they suck up all sorts of road debris into the fins of the radiator blocking air flow. Pick out the big chunks by hand and then use a stream of water from the engine side toward the front of the car to flush out all the dirt and sand. DO NOT use a pressure washer. DO NOT flush toward the motor or you just lodge the debris deeper into the radiator fins. Plenty of threads on the forum about cleaning the radiator fins.
There could be other issues as well such as a bad pressure cap on the surge tank or low coolant levels or air in the system etc. Start with cleaning the radiator fins........ Follow on to the others if the cleaning of the radiator fins does not produce significant reductions in temp.
radiator is brand new..., will be back in a bit
Thread Starter
Intermediate
Joined: Jul 2008
Posts: 36
Likes: 0
With that amount of coolant being needed you are very likely to need to burp the air out of the system. Also after driving the car and letting it cool back down, examine the upper radiator hose to see if it is sucked down. If so you have a bad pressure cap on the surge tank that is not allowing atmospheric pressure back in during the cool down process... Needs to be replaced or you will very soon need to add a bunch more coolant..
that was it, it never brove 225 even after running it hard and then pulling over. It got to 228 for a bit then dropped to 221. I'll keep an eye on it, I keep more in tune with the 2002 Z/28, this thing has been trouble free. Time to show it more love.