Engine Overheat at Idle, and a few other questions

[ylwjacket]

2005 3.0 X5, 130k miles.

This is similar to my other thread, for which I apologize, but I am wondering if my problem is not the aux fan.

My engine overheats, and a Coolant Temp Warning comes up on the dash at idle. It happens when idling at uphill locations. Doesn't seem to happen (or at least I haven't noticed it) at downhill locations. When moving, the temp returns to normal, and everything is fine. I did have the a/c on when it happened.

I had been thinking it's the aux fan, but I'm not so sure now. It was a little low on coolant, as apparently I didn't bleed it enough. I added more, until the expansion tank was full while cold. I haven't driven the car since then.

I replaced the thermostat, water pump, and upper and lower hoses. Dealer told me the thermostat was stuck open, after replacing the expansion tank after it grenading while driving. When the tank blew, all the coolant leaked out, I pulled over, and got towed to the dealer. They replaced the tank, and told me the thermostat was stuck open. While replacing the thermostat, I went ahead and replaced the water pump and upper and lower hoses.

Also, I am ordering parts for a oil filter housing gasket and valve cover gasket. When I replaced the water pump, the belts looked fine, but I am wondering if I should go ahead and replace them while I'm doing the oil filter gasket. Not sure how long those last. For $35, I figured it might be worth it to do while it's apart anyways. What's the cycle on belt replacement?

Thanks for your help.

[Zulu95]

With the AC on is the fan running? If not then you have a problem.
Belts: If you do not know how old they are replace them as it is cheap insurance.

[ylwjacket]

Does the aux fan run all the time that the a/c is on, or only after the car is warmed up?

[ylwjacket]

I just found something else that talks about the self-test mode at startup. I hear a click near the fan on start-up, but the fan doesn't move, which I guess is telling me the fan is toast.

[Zulu95]

I would do a search here for the replacement DIY and get to ebay for a new fan. The click you hear is most likely the fan relay operating.
If you want to continue troubleshooting then you need to disconnect the fan and apply 12V direct to it to see if it works but it sure sounds toasted.

[ylwjacket]

Thanks. Found one on ebay for $315 shipped, which seems like a decent relative price. I may try applying 12 volt, but it sounds like I have weekend plans next weekend now.

I'm going to attempt the fan, oil filter housing gasket, and valve cover gasket, all next weekend. Yippee.

Thanks!

[tmv]

I overhauled the cooling system along with the seprentine belts and pulleys as a 100K mi preventative maintenance. It cost about $30 for both belts.

[CTSportX5]

Could it be a fan clutch? The symptoms seem to fit.

[ylwjacket]

CT- I had wondered that actually. How would I know if it's the clutch as opposed to the aux fan? The fan spins when I start the car. I didn't loom when it overheated to see if it was spinning or not.

[CTSportX5]

Fan clutch is in regards to the mechanical fan, not the aux fan. Car overheats while idling and cools back down when in motion- with AC off. This was my basic undersanding. But I took this off e46fanatics:

There are three ways to diagnose a bad fan clutch:
1- NOISE: Fan noise is sometimes evident under the following normal conditions: a- when clutch is engaged for maximum cooling, and b- during the first few minutes after start-up until the clutch can re-distribute the silicone fluid back to its normal disengaged operating condition after overnight settling; however, fan noise or an excessive roar will generally occur continuously under all high engine speed conditions ( 2500 rpm and up ) if the fan clutch assembly is locked up due to an internal failure. If the fan cannot be rotated by hand or there is a rough grating feel as the fan is turned, the clutch should be replaced.

2- LOOSENESS: Under various temperature conditions, there is a visible lateral movement that can be observed at the tip of the fan blade. This is a normal condition due to the type of bearing used. Approximately 1/4" maximum lateral movement measured at the fan tip is allowable depending on make and model. If the lateral movement exceeds the manufacturer's specifications, the fan clutch needs to be replaced.

3- SILICONE FLUID LEAK: The operation of the unit is generally not affected by small fluid leaks which may occur in the area around the bearing assembly. However, if the degree of leakage appears excessive, the fan clutch needs to be replaced.