Bouncing Coolant Gauge - Grounding Issue?

tacocat · Post by **tacocat** » Sun Sep 22, 2013 1:37 pm

Hey everyone. Recently I picked up a 1979 528i in Anthracite Gray and have slowly been working through the minor issues that it has. One of these is a bouncy coolant gauge. When an electrical load is introduced (high-beams are turned on, for example) the coolant gauge will bounce momentarily. After recently installing a subwoofer, I notice the gauge bouncing on every kick! I worry about how much I can trust the gauge.

I read that this can be due to a grounding issue. I have only successfully found two grounds on the car: the one under the back seat and the one under the dash above the clutch pedal.

Where are the other grounds located? If anyone has pictures that would be awesome because I'm still pretty much a stranger to this car!

BimBim2oo2 · Post by **BimBim2oo2** » Sun Sep 22, 2013 4:30 pm

Clean the contacts on the coolant sensor. I had a similar issue and thats were I started and it worked

Mike W. · Post by **Mike W.** » Tue Sep 24, 2013 8:55 pm

Run an extra ground between the body and the engine and see what happens.

JamusMcFamus · Post by **JamusMcFamus** » Fri Sep 27, 2013 10:46 am

Mike W. wrote:Run an extra ground between the body and the engine and see what happens.

Trust what this man says. I had this exact issue, used his method of repair, and it solved it. I just went to the nearest Autozone, picked up a 15 inch grounding strap and used that from the strut tower to the valve cover.