Hi, just stumbled on this forum while searching for a solution to my problem. I have a 1994 318i E36 which up till now has been great. Until today that is. Everything seemed fine until I hit the slip road of a very busy motorway (rush hour, standstill traffic). I was only queuing on the slip road for a few minutes when I noticed a pinking sound, then glanced at the temp gauge and noticed it was approaching the top and the warning light had come on. So, I pulled over, turned off the engine and had a look under the bonnet. There was some steam coming from the filler cap, though there was a good visible coolant level in the tank. I let it cool then squeezed the hoses, the level dropped a little, so I added some water. I repeated this a few times. Anyway didn't want to hit the motorway while traffic was slow so I waited. Then I set off, came off the next exit and took the long way home.
The problem is here, the drive home afterwards was fine, temp stayed at normal all the way, no problems and got home (about 40 miles).
I'm fairly competent with mechanics so I was basically looking for some ideas as to why this would suddenly happen out of the blue. I have noticed now that the heater seems to be blowing cool air even when set to the hot position. I'm wondering if it could be the thermostat. If so, i assume it's stuck open, but why the overheat before that, could it go from being stuck closed to permanently open all of a sudden?
If it's an airlock, why would it just happen out of the blue while driving? If it was the water pump surely the engine would overheat permanently.
There are no visible leaks inside or out, no evidence of steam coming from the exhaust, no water in the oil etc.
Any common failures with this model?. I really need to fix it before I go on another journey.