Silver Si El Es

iTrader: (1)

So just as the title says.....When i leave the car in idle, it starts to overheat and the needle goes up a little past 3/4 of the way. But when i start and take off in the temperature needle goes back down to normal. Another thing is that the fan stays on after the has been turned off. I checked the coolant level and it is full, also checked for leaks but all the hoses are good......I dont understand why it overheats at idle and then goes back down to normal when i drive. Do you guys have any idea about what can be happening? Is it a quick fix that i can do myself?

Thnx guys

fuzzy02CLS

iTrader: (2)

Bad fan I'd say. That's a sign of low coolant usually or air in the system, but if that checks out then a bad fan is left. A bad thermostat is possible but I doubt it.

poisx7

iTrader: (1)

is ur thermostat working right. Check it . It needs to open to allow h2o to cool the engine so maybe its not opening at the right temp causing the fan to kick in and try to cool it.

just my line of thut here.

Silver Si El Es

iTrader: (1)

ok the coolant is topped off, and i just did the bleeding on it but the car still overheats at idle.....What is most likely the problem....The Thermostat or the Water Pump maybe? How hard is to check the t-stat? Ive read a few post where people cut the spring off the t-stat to keep it ofpen at all times....Is this a smart idea?....Or how likely is it to be the water pump?

Silver Si El Es

iTrader: (1)

Has anyone else had this problem?

fuzzy02CLS

iTrader: (2)

Yes people have had it & it was a bad fan or TS. The TS you have to take out to check. The fan you can test using a volt meter or test light.
Water pump is likely not the problem. They don't fail often.

dwest1023

You should replace the thermistat. It gets weak overtime, and it inexpensive to replace. That may take care of your problem and would have been the first thing I would have replaced, since everything else has checked out good. If that thermistat is not the problem I would suspect a head gasket.

fuzzy02CLS

iTrader: (2)

Head gaskets would make you loose coolant. And again that's not a common failure part on the CLS.

Zippee

When the car is idling, there is less air moving through the radiator than there is when the car is moving so seeing the temp go up some is normal. It sounds like the temp stays in the normal area so you may not have a real problem

If the temp goes up too much there are a couple of things to try. First thing to check is for dirt, dead bugs and such plugging the radiator, you can clean it out with a garden hose from the back side.

There may be build up in the cooling system, you can give it a flush (not just a drain) and refill. I'd also replace the radiator hoses while you have it empty, they can age and cause problems even if they look good on the outside.

It could also be a fan problem, when it idles and the temp comes up does the fan turn on?

Silver Si El Es

iTrader: (1)

Yes, the fan is on wether the car is in idle or if its running. The fan also runs when I turn the ignition off.

phipark

I'd definitely replace the thermostat first. It's a cheap part, so start there.

cominfromafar

The fan remaining on after turning the engine off (and even removing your key from the ignition) is an intentional feature of the vehicle. It was purposely done to remove latent heat from the system. You are noticing this more being that your vehicle isn't cooling properly and so there's "still some cooling to be done" after you turn your vehicle off. It will continue to run until the system detects that the heat level is safe (basically until the thermostat closes). Clearly the ignition switch is not connected in series with the cooling system, but i have to verify from my electrical manual.

Ideally, having the fan run until the engine is completely cool would be nice, but then there's the argument that you'd drain the battery, a warm start is better blah blah blah....

As for why your engine is basically overheating, check out what others said, thermostat, fans, etc.

Verify the voltage that the fans need to operate, it should be written on the label and should be 12V DC. Then to test them, pop off the connectors, connect a wire to each of the two terminals in the connector cavity [of the fan, it should be a female connector] and connect them to the necessary DC voltage source. Use wires of a proper guage, but i don't know the amperage that the motors pull so i'd say 15AWG or lower. If you use the battery that is in your vehicle for a 12V DC source, disconnect both posts that go to your car's electrical system first (and make sure you know your radio code and radio stations). I don't think noting the polarity of the motor matters [unless there's a diode(s) present to keep current in one direction], but keep neg to neg and pos to pos. It only matters for the vehicle because the blades needs to spin in a desired direction.

Simply connecting a volt meter in parallel across the terminals may not tell you anything about the motors. You will only be able to tell the voltage value being supplied to the fans. That would only be useful if you know that it's supposed to be a certain value, but if the fan is the only load in that circuit loop, then you won't be able to tell open voltage drop from the voltage drop across the motor. Connecting an ammeter in series will tell you the amperage and you can then compare it to what it's supposed to be.

Sorry if i made things complex, but...well i never got good grades in school
G/L, keep us posted

Silver Si El Es

iTrader: (1)

No that's good info Comingromafar, the only other thing that makes think different about what ur saying is that one night I came home from work (I drove my other car) and heard some noise in the back and it was the fan on my car running but I hadn't drove it all day so it couldn't have been hot then. Bad fan maybe? Relay?......needless to say, I disconnected the battery and went to bed

Silver Si El Es

iTrader: (1)

So I changed the t-stat and that takes care of the overheating part so I have yet to hear the fan kick on after I shut it off, but hopefully it doesn't.

cominfromafar

Sounds good, hope it is just the t-stat. But i was looking through the 99-00 TL electrical service manual and saw a "radiator fan control module" behind the radio in the center console. The TL and CL are similar, so if problems continue that module (if the CL has it) is another thing to check.