Running Hot in Traffic

[speedhop]

I live in LA so I spend more time in traffic than with my girlfriend...if I cruise at normal speeds the car runs fine and is actually running temps under the half way mark (between the .25 and .5 way mark) but once I hit traffic and it's stop and go it shoots up to the .75 mark.

Is it thermostat? Fan clutch? Water pump? All of the above!?

The timing belt was replaced 10k mi ago but the water pump was not...

Does anyone have any suggestions for something like this?

Thanks for the help guys!

[86espowa]

Make sure your fan clutch works properly. i let my car sit in traffic during the hottest part of the year with only the a/c condenser fan going and i am alright. you must have a problem.

[sumyungguy]

Im up here in the bay area so I sit in traffic as well. My car did that when I first bought it, I found out the temp switch for the electric fan was bad and the fan wasn't turning on at all. I wired it up so that the fan is on low all the time, its really simple to wire cause its a ground circuit switch.

[sticksdaman]

that happened to me last summer during that heat wave we had it was like 15 i think and i had the car idling for over an hour in one spot... what i did was just turn the heat on full blast and rolled all the windows down... it did the trick its crude but if in the situation thats the best advice i can give you for that moment.

[speedhop]

that happened to me last summer during that heat wave we had it was like 15 i think and i had the car idling for over an hour in one spot... what i did was just turn the heat on full blast and rolled all the windows down... it did the trick its crude but if in the situation thats the best advice i can give you for that moment.

haha...I've done that one plenty before. I'm looking to solve this problem for good! :hitler:

[maco325e]

Had same problem replaced the fan clutch, problem solved also replace thermostate just in case it's cheap.

[strad]

I had problems when I bought my convertible. I ended up replacing the thermostat and fan clutch, and had the radiator flushed (out of the car) by a radiator shop. Cooling system works like it's supposed to now.

So you might need a multi-pronged approach, like I did, to get it really working smoothly. Not difficult, just time consuming.

[92 mtechnic cabrio]

A guarantee to the problem would be strad's "multi-pronged" approach.

Not only will it solve the problem, but it will keep your mind at peace.

This is assuming the head gasket isn't leaking and you're blowing coolant out the tailpipe.

[redhatpat]

A water pump or thermostat problem would cause overheating all the time. Sounds like a fan clutch.

[Inoka]

test everything as stated in the bently, it sucks to replace things that are working. I believe one should be able to hand turn the clutch fan to test it. Jump the electric fan to make sure it works. Multimeter test the wires to make sure they are getting power to the Thermoswitch. Pull the thermostat and cook it in water to make sure it opens. If it's still over heats it says to replace the thermoswitch and or radiator flush.

Had similar problems (over heating in L.A. traffic) and it ended up being the thermoswitch, and after I replaced the thermostat, too much air in the system.

Search the Forum and there are some articles about ways to remove the air from the system, beyond the air release valve. Some options were to raise the front end up so the valve was the highest point.

[rcko]

ditto the last post from Inoka...

My 325 had both of these items faulty. My engine would heatsoak pretty bad after an espirited drive, so I replaced the fan clutch and that took care of taht. After I got my ac working I noticed that while chraging up the ac system and or in slow traffic with the ac on I would temp >3/4 of the way to H. For the later a new thermo switch took care of the issue.

Troubleshoot the easy items like the aux fan thermo switch using a jumper wire with the ignition on. The fan clutch by turning it over by hadn with the engine off. SHould feel some resistance.

[speedhop]

starting the "multi-prong" affect...i was tinkering today and noticed the fluid wasn't bmw coolant so that is only adding to the issue.

I'm going to flush the coolant and replace with bmw coolant and replace the fan clutch.

anyone recommend a fan clutch? I'm probably just going to get one at bma

[fwappy]

Another thing you may want to check is the thermostat housing itself. Although the thermostat gasket is supposed to prevent air from getting into the system where the housing fits together, mine was a bit corroded and was sucking air in... very slowly. This caused exactly the symptoms you are referring to. Warm up the car and open the bleed screw to see if there's excess air in the system. If so, replace the t-stat (take note the arrow goes up) and gasket, then use some gray sealant and gasket maker between the two halves of the housing to ensure NO air can leak in.

It's def worth a try if yours is starting to look a bit old and possibly corroded.