M42club.com - Home of the BMW E30/E36 318i/iS

DISCUSSION => General Topics => Topic started by: dakon on December 20, 2011, 11:49:58 PM

Title: Temp gauge question.
Post by: dakon on December 20, 2011, 11:49:58 PM

I have an E30 318is, usually my temp gauge is in this location.

(http://i1132.photobucket.com/albums/m574/dakkon1/9133cb5d.jpg)

Earlier this week i noticed that the gauge was reading hotter than normal, 1 needle past noon, i checked the fan clutch and it stopped with a newspaper.. The fan clutch was 1 year old!

So, now the car has a new fan clutch. However, the temp gauge is not rock solid like it use to be at the location that is in the picture, it is oscillating between that position and about one needle worth past the 12 oclock position (goes up at a stop light). Do any of you guys have a gauge that occelates? With the old fan clutch the temp needle was Rock solid.


A bit of history. Last year the entire motor was rebuilt, all the hoses, water pump, thermostat, radiator.. and the head went to the machine shop...

P.S. I am at a loss as to why i am having temp issues.. Everything is new.. And the system is bled, i verified this yesterday...

Title: Temp gauge question.
Post by: esager on December 25, 2011, 02:52:06 AM

I experienced a very similar problem. I replaced my entire M42 cooling system (radiator, hoses, plastic pipe, fan clutch, T-stat, etc. etc.) and was therefore confident of the system. Would get a bouncy needle or one that acted funny sometimes (sometimes running one or two needle widths above the mid-way point with no obvious reason for it to do so). Turns out it was the ground nut behind the IP...was loose. Once I tightened it up, all was well. Rock solid.

Getting to the ground nut was not super fun, but do-able. Had the cluster out to replace a burned out dash lightbulb and there it was...loose.

Good luck!

Title: Temp gauge question.
Post by: gearheadE30 on December 25, 2011, 08:32:53 AM

That's actually pretty normal. Modern cars don't do that because they have circuitry that makes the gauges less sensitive so that they read rock-solid and under half all the time so the driver doesn't panic. E30's don't do that so much. You will get temp fluctuation depending on driving conditions and when the thermostat opens and such.

there are a few things that can cause incorrect gauge readings-failed sensor (happens more than you'd think), the aforementioned ground nut, and dying SI board batteries.

Title: Temp gauge question.
Post by: rjcaptsean on January 01, 2012, 12:08:35 AM

+1 on the grounding nut behind the IP.  After pulling mine out too many times to count (FINALLY GOT THAT FREAKING SPEEDO WORKING!  but I digress...) I have found that the grounding nuts on the back are pretty important.