M42club.com - Home of the BMW E30/E36 318i/iS
DISCUSSION => General Topics => Topic started by: Thunderlips on August 21, 2011, 06:48:03 PM
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So a month or two ago i purchased a 1991 318is with 137,700 on the clock. I bought it with $2,000 in receipts from the last year that the po owned the car. I wanted to do a proper intro with pictures etc. but I've been lazy. Anyways today i was driving in manhattan when all of a sudden the brake fluid, brake, parking brake and battery light came on along with the brake lining light that has been on. Thennn the car started running hot around the 3/4 mark, the car usually runs in between the 1/4 and halfway mark never over. So I pulled over and checked everything. Brake fluid was fine, coolant was fine, oil was fine etc. But the temp gauge stayed over 3/4 I put the heat on and it didn't even blow hot, just cool the entire time. When the temp gauge hit the red the cel came on, I pulled over and let it cool down. I made it home with the hood open and the heat or lack there of on. Sorry for the essay but this is my first thread, if anyone has any thoughts or could help in anyway I'd appreciate it. thanks. -Joe
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Welcome to the 'club...sorry to hear of your troubles...
I'd start off with a compression check to be sure the motor is in good shape. The M42 isn't tolerant of overheating.
Might just be some bad grounds, flaky temp sensor, etc. Getting a good compression check will eliminate a cracked head as a culprit.
Also could be a cracked water pump impeller or a broken thermostat. Neither are the end of the world.
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Thanks, also I noticed the fan isn't spinning. So I'm going to change that, the thermostat and check the water pump.
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The main fan clutch has a habit of dying, and the resistor on the aux fan dies regularly. I had trouble with the fanstat on the radiator once as well...you can jump the wires to test low and high with the key in position 1.
I can't recall fuses or relays...but there is one for each speed. I'll post them later.
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to check the fan clutch, you can get a newspaper, start the motor and attempt to stop the fan with the newspaper if the fan stops easily then your fan clutch is toast, and is probably a good culprit for your over heating issue. i think a fan clutch costs about 60 bucks.. It does require a 32MM open ended wrench. some bmw places sell a fan clutch wrench.
like dave said these heads are VERY prone to cracking if exposed to an over heating condition.. The design of the coolant channels is not that great....make sure you get your over heating issue resolved before you drive the car again.
Also you can check to see if your coolant system is maintaining level, or if something is consuming some coolant...
You can get a compression tester from harbor freight for pretty cheap, if your going to do a compression test you might as well get a leak down tester as well as they are not that expensive, however both of these items do require an air compressor.. This way to know the full condition of your head.
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Usually when you get all of those lights on at once it's an indication of low battery voltage(fault in charging system).Low voltage causes guages and ecu's to do funny things.
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Usually when you get all of those lights on at once it's an indication of low battery voltage(fault in charging system).Low voltage causes guages and ecu's to do funny things.
^This....my aftermarket guages would be pinned, and all warning lights would come on. One time my battery voltage was so low, using the turn signal caused the car to buck, hard.
Go to a reputable shop and have them test the Alt and Battery. There is a special tester that will analyze the batt, and test the Alternator(ripple and diodes) properly. If you have to replace the alt, then REPLACE THE BATTERY at the same time.