89 BMW 325i Over heats on idle

I have had this car as a second owner since about 1998(9 years old)
I now have about 393,000 miles on it as of yesterday.(24 years now) Not bad!

I change the oil regularly, plugs, gas additive, belts, etc....routinely

Just recently had the Head Gasket replaced 13 months ago.(past warranty) Still has great power and uphill horsepower, HOWEVER, on idle or city driving at idle stop and go traffic, the engine starts to over heat.

I have already had the following done in the last 3-6 weeks:

A) Replaced the over flow reservoir, CAP, checked all the hoses,[/B] [/I][/B]
B) Replaced(Not a power flush) the Radiator fluid.(several times)
C) Replaced the Thermostatic Fan(original part was still there after all these years)
D) Finally RE-Replaced the Thermostat as the mechanic swore he did that with the Head Gasket job(???)
Everything seemed fine for about 10 days and NOW it is heating up again on idle at the "drive thru" and then cools off a little at the next light, but cools down to 50% at highway driving 65 MPH back to "Normal".
The Radiator is new and after market. 2-3 years old now.(Never flushed/cleaned)

Oh, today when I started the engine up, there was white smoke out of the tail pipe until it warmed up. This has only recently happened(I added some Techtron to the gas fill up) Always Premium, even with these Gas Prices.

Is it possible there is still AIR in the system? Or what???

Shall I bleed it off at the Overflow CAP OR, shall I do it at the Bleed screw on the Thermostat Housing ? Or do nothing?

The radiator fluid seems fine and is at 50% near the TOP even though the mechanic topped it off last week.(NO Visible Leaks anywhere)

Just changed the OIL and it looks fine.

Just replaced the plugs and the response and power is GREAT!!

I was getting into "Rush hour" stop and go traffic and I was heating up on a coast too. WOW!

Help????

John

Manual transmission?

Manual 5 speed

Is your fan operating? Sounds like maybe not enough air is getting to the engine, especially since it happened at stop and low speeds

I just replaced the Thermostatic "
clutch" Fan in front.(Unless the Mechanic put it on wrong??)

I've done everything but power flush the radiator.

Do you really think it can be the clutch Fan with all I've already done?

It would have heated up sooner. I had that done about 7-10 days ago.

a nice test, drive around with the ac on (if your in the colder areas, run high heat defrost with ac on) and watch the temp gauge. if it stays the same temp, then most likely its the fan clutch. if it continues raising then youll have to some more digging.

Originally Posted by downhiller

a nice test, drive around with the ac on (if your in the colder areas, run high heat defrost with ac on) and watch the temp gauge. if it stays the same temp, then most likely its the fan clutch. if it continues raising then youll have to some more digging.

I second that test!! The symptoms just sound like air to me, but I've only been a mechanic for 3 months so I'm not 100%

And make sure you do the test when your bimmer is beginning to be over normal operating temp, if it goes back down then that's probably your issue

Ok, let's stop all of the guess work. First thing, top off the coolant. Get a newspaper and roll it up. You will use this to test the thermal fan clutch. Open the coolant reservoir, start the engine and look into the coolant reservoir. With the engine running, you should a dribble of coolant flowing from the small vent hose back into the coolant reservoir. Rev the engine, this dribble should turn into a steady stream, indicating that your water pump is functioning. Securely replace the reservoir cap. Next take the rolled up newspaper and attempt to stop the fan from rotating. With the engine cold, the fan should stop. With engine hot the fan should shred the newspaper. If the car pass all of these test let it cool down. Loosen the vent screw on the coolant water neck. Start the engine and let it get to operating temp. You should hear air escaping from the vent hole. As all of the air escapes and the coolant thermostat opens, coolant will spew out of the vent hole. When only a steady stream of coolant is expelled, tighten the vent nut. The last thing to check is the two speed coolant temp sensor located in the right side of the radiator. This sensor activates your electric fan. Check those things and let me know your results. :beer:
Your white smoke at startup is caused by leaky piston rings. They allow oil to get pass the rings when cold, but as the engine heats up they expand and provide a better seal.

Water pump is cavitating.

m

you need to add nitrous so it can cool it down

Originally Posted by BigBoy740il

Your white smoke at startup is caused by leaky piston rings. They allow oil to get pass the rings when cold, but as the engine heats up they expand and provide a better seal.

white smoke is either moisture during cooler morning startup since its running rich to warm up or coolant in the combustion chamber.

blueish color during startup is valve guides, while running is normally piston rings.