Re: temp reading on gauge question (archive)

I just bought my M5 about 2 months ago and have been concerned with engine temperature since day one. I have replaced the fan clutch, thermostat, aux fan switch, fan resistor, and had the radiator flushed. None had any affect. The gauge would still indicate it was running hot if I ran at low speeds for any period of time. Once the gauge got over 1 o'clock or so it would sometimes jump around pretty erratically, often jumping right from 1 o'clock to the red zone. I was pretty convinced that it was either the gauge itself or the sending unit, so I ordered a sending unit.

Then I found an article that said bad batteries on the SI board could cause this sort of behavior. Usually all gauges would be acting funky, not just the temp gauge, so I didn't have a lot of faith in this as a solution. Being desperate, I decided to try it anyway. I cracked open the instrument cluster and found that there are two 3 volt lithium batteries (I was expecting to find two AA NiCd's in there as mentioned in the article). Anyway, the positive contact on one battery had come unsoldered. Both batteries tested fine, so I resoldered the contact and closed it back up. I immediately took the car out to try and get the temperature to climb up by simulating rush hour traffic. I've always used this same test (and failed) in the past whenever I replaced one of the aforementioned cooling system components. This time the gauge held steady and creeped just past 12 o'clock at the very most. The inspection light also came to life for the first time. It may be too early to tell, but I think I have fixed my problem. I plan on testing it some more at lunchtime when it is a little warmer out. I'll let you know how that goes.

Hope this helps.

Sean

on our beloved m5's what is the normal position of the temp needle. in my old 528e it was usually between 10 - 12 o'clock, and 12 when it was really hot(like rush hour) but never higher. I know the engines on the s38 run hot, but what do you guys see with your engine. I'm just trying to troubleshoot my temp problem, but first want to know if i even have a problem.

thanks ahead.

alex 88 m5

Follow Ups:

[ Follow Ups ] [ M5 (E28) Message Board ] [ Msg. Board FAQ ]

Questions, comments, or problems, please visit the Roadfly help desk.