Engine temp problem

I have a '96 SL with 155K. Sometimes the engine temp guage reads
full cold and the engine idles high when I've driven long enough that
it should be up to normal temp. Then all of a sudden, it will jump
up to normal operating temp. Then it may or may not go cold again.
Some mornings it does this, but not every day.

Do you think it is an electrical problem, or a sticky thermostat?
The thermostat is the original, 11 years old. The coolant temp sensor
on the end of the block was replaced a few years ago.

Larry

 

I had the same problem, and in my case, it was electrical. the coolant
temperature sensor wire either has a break in it, or the connector is
loose. The connector would be the 1st thing I'd check - mine turned out
to have a broken tab on it.

 

The CTS (Coolant Temperature Sensor) is a known weak point on these engines
and go bad quite frequently. If the connector looks good, then replace the
CTS. Cheap part and easy 5-10 minute fix.

Bob

I had the same problem, and in my case, it was electrical. the coolant
temperature sensor wire either has a break in it, or the connector is
loose. The connector would be the 1st thing I'd check - mine turned out
to have a broken tab on it.