Re: ken and ron...... (archive)

: Suprisingly i have had these very same symptoms on my car (i) high temp after restart and (ii) high temp in jam.
: This started after i changed my radiator hose, which previously was leaking and caused my car to overheat. After this, the things above started to occur, although not at a frightening rate (i have had major overheating problems with a previous e28!!)
: After reading the replies, i think the first part about the high temp after restart SHOULDN'T be normal as it hasn't happened b4.
: I suspect from ron's symptoms that it must come from the thermostat as my previous overheating must have affected that.
: thanx to kenny for bringing up the matter and to ron for the suggestions....
: regards
: izzy
:
: : Kenny, first, don't worry about the momentary high temp reading after restarting your car, that's normal, as long as it settles in after about a minute, or until you get moving and air gets across the radiator.
: : As for the temp creep in traffic, it can be several things, but don't ignore it. Heat-ups like the ones you describe can lead to head gasket troubles which is big $$$. Check the following and see the archives where noted.
: : 1. thermostat--if it's opening/closing correctly, the upper rad hose should be HOT after driving a while. Cheap fix--$20-30
: : 2. auxiliary fan--this is the small electric fan that sits in FRONT of your radiator. It does nothing while driving, but in traffic, its role is to switch on at preset temp intervals (before the RED zone) and when A/C is on and pull air into the radiator. The ez check on this one is to switch on your A/C with car in park, get out check to see that the fan is operating. Possible causes if it's not can be bad fan, bad resistor, or simply a blown fuse. Archives have much info.
: : 3. fan clutch--again, doesn't do much while your car is moving ("free-wheels"), but in traffic, it's supposed to "grab" and pull air across the engine. Check archives for more info. About $65-70 for a new one)
: : 4. Check the radiator cap and check/tighten all hoses. Pressure losses usually show up when car is in traffic. Usually small, no leak or smell, but just enough to allow pressure to escape.
: : 5. Get the radiator checked. It SHOULD be ok with your mileage and vehicle age, but i've heard of a few early failures. They usually last about 8-10 years if properly maintained. A new one will set you back about $300 +labor.
: : Good luck and get it fixed before the really hot stuff gets here!
: : ron 89 525i

Izzy, the high temp after restart is i believe caused by the position of the temp sensor (and i could be wrong, i did bad in college thermo :o). It sits in the upper most cavity of the system just aft of the thermostat hosing. When you shut your car down, basic thermo says the hottest gases are going to try to rise. When you start up again (before allowing the system to cool down), the sensor is effectively getting a "blast of steam." Until you get moving or get the coolant circulating again, it reads a LITTLE BIT HIGH, usually no more than a needle width or two, but should settle back down in short time (1-2 minutes). If your symptoms are anything outside what i described above, it's time to start looking at the cooling system. A new radiator finally did the trick for me--had the original with 123k, i got tired of the needle riding on the high side of center, all is well now, even handling this 90+ stuff we've had lately, riding just LEFT of center now. Let me know how your diagnosis goes.

ron 89 525i (runnin' cooooool !)

Follow Ups:

Ron Izzy 00:03 5/09/2000 (0)

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