In Reply to: 88 M3 Running Hot posted by Chris Schrimsher on May 03, 2000 at 12:17:13:
PS Still without my car since Friday - darn BMW dealership keep sending the wrong switch apparently. There are differenct switches depending on wether u have air con or not.
: Three weeks ago I purchased an 88 M3 with 57,000 miles from a friend. It's in pretty good condition however the temp gauge hovers between a little to the right of center up to
: 3/4's. This past weekend it even reached the red zone before I shut it down.
: Here is what I have observed:
: -Coolant in overflow tank is at mid point seam, or 1/2 full. I believe this is right where it should be.
: -Coolant leaked a little three weeks ago but not any more.
: -Driving with heater running keeps temp gauge in the normal, mid-point range.
: -Turning on heater will immediately cause temp gauge to drop from about 3/4 down to the mid point.
: I've read some of the threads on similar problems and yesterday evening I ran the car in the garage so that it would heat up. I was able to get the temp gauge just past 3/4's before I shut it down. I had to rev it a bit to get it this high otherwise it would have leveled off somewhere between 1/2 way and 3/4.
: Here is what I've checked out:
: -The auxiliary fan in front of the radiator NEVER ran but the one behind the radiator did.
: -I carefully removed the pressure cap after shutting down and used a cooking thermometer to measure the temp. It was 170 F whereas the temp gauge below the tach read about 150 F.
: -The cap hissed a bit as I removed it so I assume it's holding pressure ok.
: -Both upper and lower hoses attached to the radiator were hot so I assume the thermostat is functioning and the radiator is not clogged.
: -I assume the water pump is fine since it no longer leaks coolant.
: -I checked ALL fuses and they looked ok.
: -I manually rotated the auxiliary fan blades and they turned so it is not seized.
: The Plan:
: -Remove the auxiliary fan and have it tested. I assume this can be done, right? Replace if necessary.
: -Flush radiator while it is out.
: -Remove and test thermostat while radiator is out. Replace if necessary.
: -Take a closer look at wires running from thermostat to make sure they are not brittle and broken.
: -Flush entire cooling system.
: -I'm troubled with the disparity between the temp of the coolant I measured with the cooking thermometer and what the temp gauge below the tach reads.
: -Is it just the coolant is low?
: -Will I be able to tell if the auxiliary fan is bad?
: -Will I be able to tell if the radiator is clogged?
: Am I missing anything?
: Chris Schrimsher
: [email protected]