Coolant Level Sender
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Joined: Oct 2010
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From: Memphis, TN 1987 S4
Coolant Level Sender
Hey gang,
I’m getting a check coolant level alarm on my 89S4. The level is fine. I’m not loosing coolant from anywhere. Is it possible to test the sender via a multi meter? Is there anything else I need to check? I did change my “J” hose on the bottom of the expansion tank. That fixed the leak I had. I let it run for 20+ minutes without the cap so I think it should have burped. I ran it so long the coolant was approaching the top. Not enough to spill out the top but it seemed like if I kep it running, it would have overflowed.
thoughts?
I’m getting a check coolant level alarm on my 89S4. The level is fine. I’m not loosing coolant from anywhere. Is it possible to test the sender via a multi meter? Is there anything else I need to check? I did change my “J” hose on the bottom of the expansion tank. That fixed the leak I had. I let it run for 20+ minutes without the cap so I think it should have burped. I ran it so long the coolant was approaching the top. Not enough to spill out the top but it seemed like if I kep it running, it would have overflowed.
thoughts?
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Joined: May 2002
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From: Roswell, GA
Not sure about this, but the float itself might be the failure point - the float after many years sitting in hot coolant begins to decay and swell.
I pulled two last weekend and they crumbled, leaving behind the magnet ring. The sensor did still work when I moved the ring out of range.
Maybe a 3D printed replacement would save them?
I pulled two last weekend and they crumbled, leaving behind the magnet ring. The sensor did still work when I moved the ring out of range.
Maybe a 3D printed replacement would save them?
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Joined: May 2002
Posts: 9,231
Likes: 1,318
From: Roswell, GA
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Thread Starter
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Joined: Oct 2010
Posts: 1,337
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From: Memphis, TN 1987 S4
I cleaned the float and it began to work. Probably just temporary but there was a lot of gunk. I’ll plan to get another one and a metal expansion tank in the near future. Thanks for the help.
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From: Milwaukee, WI
Generally I'm not a fan of ghetto fixes but I was able to effect such a repair which, a) being invisible, b)working perfectly and c) given the cost of replacement sensor, I was perfectly satisfied with and will be 100% reliable for decades to come. I fashioned a replacement float from closed cell foam. You need to clip off the bottom "T" disc that holds the float in place and salvage the ring magnet. The resulting foam cylinder is much smaller than the original material as it has much higher buoyancy. I added a SS washer for necessary ballast but it distorts the magnetic field so play with the new magnet/foam assembly to ensure it only activates the reed switch in one (low) level position. Initially mine activated at the low point but also at its highest point, which is not correct behavior.
Nordschleife Master
Joined: Jan 2013
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From: Kaukauna Wisconsin
You get to it by lifting the hood.
Somewhere on here is a pic of what's under the hood. Labelled and everything.
There's a similar pic of what's underneath the car.
If someone would post or link that, it'd be great.
The coolant tank is at the back of the engine bay, on the passenger side (right side for left hand drive cars).
It has the 'radiator cap' on top.
It was originally white plastic. By now it's usually pretty yellow.
Pro
Joined: Feb 2010
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From: Cape Coral, FL