Not really overheating, but...

[baksa]

These days were really hot, around 36-37 degrees Celsius.
My temp needle stays just a bit to the right of half mark, but sometimes when A/C is on in driving, when I stop, car is parked for quarter of an hour, when I put my key in contact position, temp gauge is around 3/4 mark, and when I start the car and drive for 10 secs, temp gauge goes back to normal position.
Is it t-stat or something else?
I've heard that lot of cars have just the same position just above the half mark as normal temp, but others say that it should always be dead centered or just below center. Maybe older cars warm faster and on higher temps?

[Dave M]

I don't nkow about 15 min, but immediately after engine shutdown on a hot day, the lack of circulation will cause an increase in engine temp. You're essentially locking very hot fluid in your engine and removing its cooling capability. I've never seen it close to 3/4, but definately above the 12:00 mark.

Someone else may be able to speak to the 15 min.

Dve M

[Gayle]

This thread discusses the various options.

http://www.bmwe34.net/e34main/trouble/overheating.htm

I had overheating issues last summer. It was a blown fuse to the fan clutch. In getting to that diagnosis, I had lots of discussions with people about the questions you ask.

My indy who is one of the leading classic bmw gurus in the country says a hair over middle is ok.

When I had the first overheating issue, people on this board told me this:



just to let u know when u have the m30 on for a while
and then turn it off the heat soaks the engine and coolant
and if u turn it on again before it cools it'll be a little hotter
than normal, but it always drops down to normal just like
yours did..so i suspect it got up to 3/4 in part to the heat
and partly cuz it was just run.....am i right?

That said, I would still check the thermostat and fan clutch. It is good that you are paying attention to this. Preventing overheating is always smart, as it can cause very expensive damage.

[E34 530]

This thread discusses the various options.

http://www.bmwe34.net/e34main/trouble/overheating.htm

I had overheating issues last summer. It was a blown fuse to the fan clutch. In getting to that diagnosis, I had lots of discussions with people about the questions you ask.

My indy who is one of the leading classic bmw gurus in the country says a hair over middle is ok.

When I had the first overheating issue, people on this board told me this:



That said, I would still check the thermostat and fan clutch. It is good that you are paying attention to this. Preventing overheating is always smart, as it can cause very expensive damage.

The fan clutch isn't run by a fuse, I'm guessing you meant the auxilary fan.

[VentoGT]

My car's fan clutch is toast and this is what happens to me--most likely, you need to replace the fan clutch. Get the SACHS, not BEHR part. The last batch of BEHRs have been bad.

[TC535i]

Fan clutch and aux fan don't work when the car's parked and off, so that's a moot point.

It's called "heat soak", and it's because the coolant isn't circulating... I wouldn't worry about it... in fact, I DON'T worry about it; my 535i does the same thing too, right up to 3/4 on hot days... no biggie, goes right back down when I start it up and coolant circulates out of the motor.

On a side note, I always turn my A/C off about a minute before I get wherever I'm going. Helps dry out any condensation before you turn the car off, so you don't end up with a musty smell... may help cool the car a little before you shut it down too.

Also notable, I got an "updated" thermostat in my car, and it runs slightly above center now. Apparantly this is normal, and it's to reduce emissions (burns gas more efficiently at that operating temperature). Hasn't affected overheating or anything, it just drives a needle width or two above center and stays there... fine by me.