MFTS Any Recommendations?

SJM Auto -Technik sjmauto at
Thu Sep 5 15:55:06 EDT 2002

[ Picked text/plain from multipart/alternative ]

I don't specifically recommend the use of the earlier 4 prong VDO brand
sensors, I only expressed some of my failure experience with both the 4
prong and 3 prong versions. The 4 prong version "may" still be available,
but most aftermarket suppliers I deal with only sell the 3 prong version.

My disparaging comments on the 3 prong versions were related to failures I
had within 12-18 months after installing new 3 prong MFTS's on 4-5 of my
customers 200TQ's. I took apart 2 of these failed three prong sensors, and
found coolant inside the switch area. This switch is machined out of a
solid piece of brass/bronze? and the only way the coolant could make it
inside the sensor, would be for it to come through some cracked threads on
the sensor or from some porous metal. I again "theorized" that
overtightening of the sensor "may" cause the threaded area to crack but I
don't know for sure what caused these 4-5 three prong sensors to fail.

I have not had any failures in the past year on the 3 prong sensors that
were replaced.

I never stated that the rubber boot causes the switch to go bad, only that
the boot can collect coolant and other moisture as it gets old and doesn't
seal well and this moisture or coolant can corrode the electrical
terminals. If you live in an area that salts the roads, leaving this boot
on is recommended. Cutting a small drain hole in the bottom is a better
alternative to removing the boot completely.


Scott Mockry
SJM Autotechnik

More information about the 200q20v mailing list