re: E36 M3 overheating

["Nick" <nikog@xxxxxxxx>]

Steve,

I would suspect the water pump. The early M50 engines had a faulty design
where the water pump's impellor was plastic, while the shaft was steel. Over
time, the plastic fatiqued and cracked, causing the impellor to freely spin
on the shaft. This would in turn cause the car to over heat. The repair is
covered under the 4yr/50K warranty. The new water pump uses a steel
impellor. I don't know when they fixed the problem in production, but my
6/95 build M3 had the plastic impellor (and now the steel one :).

Nick
'95 M3

>Date: Fri, 23 Oct 1998 08:07:26 -0400
>From: "Steve Graalman" <steve.graalman@domain.elided>
>Subject: E36 M3 Supercharged Overheating
>
>Would anyone care to offer their thoughts on what my problem could be.
>
>The Problem: After 4-6 Laps on Summit Point Raceway,  the car overheats and
>boils over very suddenly. The temperature gauge reads normal then suddenly
>it is pegged.  I do not see a gradual overheating, just a binary normal to
>hot.  It has never overheated on the street even when driven very
>aggressively. There are no leaks in the cooling system.  A hydrocarbon
>sniffer measured only 8 PPM in the coolant, so it appears the head gasket
is
>fine. The car is a 95 M3 with the ERT Vortech Supercharger installed.  I
>believe the supercharge is providing 6 lbs. of boost. I have the bigger
>throttle body and free flowing exhaust.  I have never seen any mixing of
oil
>and water, water vapor at start up, or water puddles under the car.  I am
>frustrated!  Any and all advice would be welcomed!
>
>Thanks,
>Steve
>
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