Overheating only when sationary ?? 91 ix

[EA8]

Here's the deal. The car runs perfectly fine while I'm driving (not a darn thing wrong). Once I stop and keep the heat on, I can watch the temp gauge move all the way up from 1/4 till 3/4 and sometimes past. Occasionally I get this small hint of radiator fluid smell in the cabin too when this happens.

Any ideas? Sorry if this has been covered before, if so, just lead me to the right link ... Appreciate it


Cheers

[bmwpower]

I'm sure it's been covered, but I'm too lazy to find the link.

How hot does it get?
Overheating when stationary is usually due to a bad fan clutch. No air flow when stopped, so the car heats up. When moving, incoming air cools the engine enough to appear to be fine.

BUT, if your smelling coolant AND there's no obvious leak in the engine compartment, I'd suspect your heater core is leaking.

Try turning off your heat and fan and see how it reacts.

[EA8]

Actually, that reminds me. Occasionally (not all the time) when the heat goes up past 3/4 of the gauge, I will see a few drops of coolant on the ground.

As to how high does the temp get, the first time it happened it almost got about half way between 3/4 and max, before i realized anything (kinda freaked out and shut the engine off right where I was :D)

[Farbin Kaiber]

Looks like the fan clutch has already been covered.

[EA8]

So Could a bad fan clutch also cause a minor leak?

I was also thinking about buying the dye kits and running it through the system to find out where exactly the leak is coming from? Are these dye's safe for the engine and is it worth my time using it or not?

Thanks

[bmwpower]

Fan clutch won't CAUSE a leak directly, but could indirectly cause a leak. If the car is overheating due to a bad fan clutch, this will put stress on the system which could cause a leak.

Park the car overnight and check the driveway in the morning. BTW, if it's the heater core, check in the trans tunnel area as there are weep holes on either side of the tunnel. The weep holes allow coolant to leave the HVAC box and not flood the cabin if the core is leaking.

If it's leaking somewhere near the engine, you have more discovery to do.

[EA8]

I'll give that a shot tonight. If I wanted to do some more discovering to find out where the leak is, do you think those coolant dye kits are helpful or are they a waste of money?

Thanks for your help bud ...

Cheers

[devonjordan]

WTF color would they dye coolant?

BMW is blue, and everyone else is neon green/yellow, no matter what in a dirty engine bay you will only see liquid. I'd say no to the dye.

[EA8]

The dye I am speaking of a an ultra-violet (UV) sensitive dye, that would only show up under a UV light. The kits usually include a couple of 3-4 ounces bottles of the dye and a UV light. You would basically dump one of the bottles in your radiator, let the car run for about 20 minutes with the heat on (to circulate throughout the entire heating and cooling system), turn of the car and then use the UV light to detect where the leak is.

sorry for not clarifying what I meant. Didn't think someone would actually think it was a color dye.

Being that I do all my work in my parking lot (college student - haven't gotten a garage yet), I figured this would help me find out where the leak is. I just wasn't sure if these things had any drawbacks.

Cheers

[gearheadE30]

Not really a drawback, but I would flush the system after using it. My guess is that the coolant is getting hot enough that the pressure release valve is letting some of teh excess coolant out. I'd track down the cooling issues first.

Possible issues could be the cooling fan clutch, the water pump, aux fan, and the thermostat. The clutch is the most likely. The water pump is probably okay, because a bad one usually results also in blown bearings and shredded belts. The aux fan normally comes on to prevent the motor from overheating. It also should come on when the AC is activated. Check your fuses; the plug for the fan is behind the driver's side headlight bracket. Turn the AC on to see if teh fan comes on. Lastly, a bad T-stat can do 2 things-cause the motor to run excessively cool for a long time (stuck open) or cause the motor to run hot (stuck closed) due to a lack of coolant flow. The t-stat is designed to stick open if it breaks, but I have seen at least 2 that got stuck almost closed. The extra airflow when the car is moving may be just enough to keep the engine temps down. I suppose lastly, you could have a clog in the water passages in the motor, which a simple flush could fix.

[Rolla1990]

When cars overheat they vent coolant from the overflow. Make sure your fan clutch is working, don't worry about the leak.

[EA8]

Guys ( bmwpower, gearheadE30 & Rolla1990), Thank you very much. You guys have explained it well enough for me to at least have a better idea of what I might be dealing with.

Now for the fun part, whats the best way to actually check and see if the fan cluth is a the problem?

[EA8]

:d

[bmwpower]

With the car cold, try to spin it by hand. It should have some resistence and not spin freely.

With the car hot, the fan should be putting out a decent amount of air flow in the engine bay. You should feel it from standing next to the engine bay.

Supposedly you can test also by trying to stop the fan with a roll of newspaper with the car running at temp. Never worked for me completely since it's subjective.

[EA8]

Alrighty. So I just tried spinning the radiator fan and it moves free like the wind (no resistance what so ever). According to you guys, this is a sign that the problem is the fan clutch, thus I am going to order a new fan clutch tonight (unless you guys have something extra to add).

When I do get it, Whats the best way to change it? actually, how do you change it and how hard is it? any DIY?

Cheers