I just bought a 1975 BMW 2002 fixer upper to work on with my daughter. Work's progressing nicely, but I have one minor problem I can't figure. The car had been running fine for about 500 miles or so over the last week, but suddenly, Thursday night it overheated. The radiator water was full and tepid, so I figure a stuck thermostat, bad water pump or something like that. Haven't cracked it open yet. Engine oil clean, not cloudy, not foamy. That's not the question. The question is the overheat idiot-light came on and even thought the car is stone cold now, the light stays on. I'm thinking a bad sending unit? Any ideas appreciated! Image Unavailable, Please Login
hey Dean, you got some cool cars....an old Fiat, two sweet BMW's, your wife's CLK. why don't you put those in your "garage" instead of all those crappy Caravans?
Looks that way to me. There might not be anything wrong with the cooling system. Get one of these (pretty cheap these days) and you will know for sure. Image Unavailable, Please Login
I think that would be great to have. Use it on the grill and smoker too! I guess, I left out an important part, there is a temp gauge as well as an idiot light. The temp gauge seems to function fine and rapidly rises into the red zone. as the engine runs.
On a positive note, the CLK is growing on me, it's what we usually take when we go out; what a nice car.
Sounds like a stuck thermostat. Take it out, close 'er up and start it. If it doesn't overheat, we fixed it. Get a new thermostat at your leisure. If it does overheat, next stop is the water pump. Hell, this should be easy for you, I thought plumbing was your specialty. D
Oh, and just pull the plug on the back of the idiot light, that'll take care of that little issue too. Never have to worry about it coming on again and cluttering up your dash with a pesky warning. D
well duh. I got really annoyed by those brake warning lights. and the one that tells you in the alternator is working, and DAMN, that overheat warning came on ALL THE TIME. It really pissed me off, so I pulled the fuses for all that stuff. You might be able to find them floating around in the trunk, under the carpet if you look real hard. They'll be right next to the backup ignition stuff for the Dinoplex, that I disconnected. DM
Shouldn't really need that. Nothing in the car to drain the battery, what with all the electrical stuff disconnected. you'd be better off installing one of these. DM Image Unavailable, Please Login
As old as the car is I suspect the light is actuated by a temp switch. Which is a simple Bi-metalic switch that closes at a specific temp. Sounds like it closed and stayed that way. It should be a 2 wire sensor that is connected in the cooling system somewhere. 1 wire if it uses chassis ground. You really need a wiring diagram or schematic of the car. But if the light is on when the motor is cold that would be it I'm sure. Good luck. Probably should look for a BMW forum.
yep, that's an important part You can ignore the annoyance of the light being stuck on (it'll be some dorky electrical problem, you'll have twenty more before you've finished sorting the car) until you've fixed this very real and potentially engine-killing overheating problem.
