Causes for overheat indicator? Preferred 02?

Phil and Judy Rose pjrose at
Tue Apr 15 12:21:34 EDT 2003

At 12:41 PM +0000 4/15/03, Mike Del Tergo wrote:
>It appears that even thinking about dropping my aux rad from the Avant is
>causing problems.  Yesterday I got the "low coolant/overheat"
>indicator symbol on the dash readout.  The water temp guage said below 1/2,
>the oil temp was below 2nd has mark, and the rad fan had not cycled and the
>overflow tank is not particularly pressurized.  The coolant level sensor
>checks out fine, so I am thinking Multi Function Temp Sender or regular temp
>sensor in back of head.  If I read Bentley correctly, the head sensor flows
>to the MFTS then to the gauge idiot lights?  Any ideas? Also any BTDT for
>Bosch generic 3 wire 02 for the car, PN 13913?

Ideas? BTDT? Of course. ;-)

  Both items have been much discussed in many threads The generic
3-wire Bosch oxy sensor is very commonly used in these cars--and I
believe Scott M. has some info on his web site about that (and most
other things, too.) I spliced-in a Bosch generic 3-wire a couple of
years ago and it's working fine (have them in both cars, actually).

The "low coolant/overheat" warning is a common symptom of MFTS
failure. If this is your situation, you'll also find that your boost
is limited to about 1.4 bar and your A/C is inoperative. The coolant
level sensor will also generate these symptoms if it is defective,
but that seems to happen much more rarely than MFTS failure. The MFTS
failure is, as you probably know, very common--especially the 3-pin
version. The 4-pin (VDO) version is available for the same price and
is possibly (hopefully!!!) somewhat more robust. Generally, when the
4-pin version fails, it affects the temp gauge reading.

*  Phil & Judy Rose           Rochester, NY  *
*        mailto:pjrose at       *

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