Over heating issue
Thread Starter
Cruising
Joined: Dec 2007
Posts: 11
Likes: 0
From: Puyallup WA
Over heating issue
I have an 01 that is running hot. most of the time. the fans dont want to come on all the time. is there a thermo fan switch that might be an issue? I replace the thermostat which didnt make any difference.. i need to run the heater on high to cool it down. any ideas?
Melting Slicks
Joined: Sep 2008
Posts: 3,138
Likes: 802
From: Espanola New Mexico
Under what conditions is the car overheating, is it in traffic or on the highway? The low speed fans should come on at a specified temp, of the top of my head I don't know the number, then the fans go to high speed when a higher temp is reached. The fans shut off once your car reaches a speed of 35mph, because they will restrict air flow if they remain on. Other things that come to mind is a bad water pump, or the cooling system has air trapped somewhere which has to be released, I am sure somebody will post a procedure on how to burp the cooling system.
Thread Starter
Cruising
Joined: Dec 2007
Posts: 11
Likes: 0
From: Puyallup WA
thank you. yes its in traffic and in town driving. I know the fans work just not all the time. it wants to run at 199 to 215 temp warning light doesnt come on. waterpump seems to be ok as the water is moving.
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Thread Starter
Cruising
Joined: Dec 2007
Posts: 11
Likes: 0
From: Puyallup WA
what are the set points? and if not coming on when they should is that the temp sensor that might be bad?
this morning it never got above 198. like the fans were running like they should?
this morning it never got above 198. like the fans were running like they should?
Pro
Joined: Jan 2016
Posts: 524
Likes: 126
From: Sandown NH
Melting Slicks
Joined: Jan 2009
Posts: 3,275
Likes: 739
From: Miami FL
I'm including here a description of how fans are commanded, so you can compare it to your car.
NORMAL fan operation on a C5 is as follows:
Low Speed - Triggered when coolant temperature reaches 226°F. When the coolant temperature drops to 219°F then the fans are turned OFF.
High Speed - Triggered if the coolant temperature rises to 235°F during low speed operation. When the coolant temperature drops to 226°F then the fans drop back to low speed.
With AC turned ON the cooling fans come ON in low speed mode when the coolant temperature is about 185°F. The fans remain ON in low speed mode until coolant temperature reaches 235°F, then they go into high speed mode.
If the vehicle speed exceeds 35MPH the PCM turns OFF the fans regardless of the coolant temperature. Air flow through the free-wheeling fans should be enough to keep temperatures within parameters, as long as the radiator fins are not plugged up. If they are plugged up, then the coolant temperature will rise and the fans will NOT come ON unless the car goes below 35MPH.
Melting Slicks
Joined: Sep 2011
Posts: 2,258
Likes: 543
From: Appleton WI
From your description it doesn't sound like your car is overheating. Is this just a recent observation of yours or did you do something to the car that now you think it is overheating?
A no cost thing to do is check to make sure you don't have any debris stuck in the radiator. If you poke your head under the car, you are going to see the AC condenser. The radiator is actually behind the condenser. There is about a 1" gap between the two. See if you have anything built up between the two. If yes, it is easier to attack the clean out from above. You can use compressed air or a water stream. Be careful not to bend the fins. The most effective way is to remove the radiator. The second thing to check is make sure there isn't a plastic bag or something stuck in the fans. I had a black plastic bag get into the fan. I couldn't readily see it but with the engine cold, I reached down and couldn't spin the fan. I kept searching and found the bag.
A no cost thing to do is check to make sure you don't have any debris stuck in the radiator. If you poke your head under the car, you are going to see the AC condenser. The radiator is actually behind the condenser. There is about a 1" gap between the two. See if you have anything built up between the two. If yes, it is easier to attack the clean out from above. You can use compressed air or a water stream. Be careful not to bend the fins. The most effective way is to remove the radiator. The second thing to check is make sure there isn't a plastic bag or something stuck in the fans. I had a black plastic bag get into the fan. I couldn't readily see it but with the engine cold, I reached down and couldn't spin the fan. I kept searching and found the bag.
