1998, BMW 528i, 170K, E39, M52, overheats in traffic, head gasket ??

Question

1998, BMW 528i, E39, M52, 170K, overheats in stop and go traffic. Temp needle comes back to middle with I start driving again. Also, there is some squeaking, squealing noise coming from the engine (gets louder with AC on), which started around the same time as overheating problem. Repair shop (not BMW dealer) says that its the head gasket that needs replacing for $1800 or he can put Stop Leak to see if that fixes the problem. I have the car for about 2 years, last 30K, with no other problems at all.
So, what would your suggest ?? Do I just try Stop Leak or spend the $1800 for the head gasket or get a opinion from the BMW dealer ($175 for diagnosis)? Also, would the new head gasket fix the overheating problem or could something else be causing the overheating ?

Answer 1

There is something wrong with the diagnosis. If you have the head gasket leak, the overheating problem won't be limited to when you stop at the traffic.

The symptoms of head gasket issues are:
1) external oil leak (you can see it)
2) oil leak into coolant (milky coolant)
3) fouled up plug (black stuff on spark plug)
4) exhaust gas coming into cooling system (which shows up as ultra-high pressure in the coolant reservore, which can look like over-heating boil over, and oil droplet in coolant)

If your car cools down when you start to move, the problem probably is faulty cooling fan/fan-clutch/control circuit, or pluged up radiator externally or internally.

You should insist a good indicator of headgasket problem before authorizing such an expensive repair.

I do not suggest stop leak. Those stuff have no ability to distinguish small gap from actual leak. It can plug up water pump, radiators, or other small passages.

Get a second opinion. In my personal opinion, you have other issues.

Answer 2

The belt's have tentioners and these are a common source of the squeeling that your describing so check those. Also the water pump has bearings in it that if bad will squeel, to check that just grab the fan and wiggle the pully on the front of the waterpump, if it move side to side the bearings are bad. Good Luck. Hope this Helps.