88 Dodge Ram w/ 318. Okay, so I pulled both valve covers (quite a pain, btw). Had to remove the brake booster on the drivers side, which meant that I also had to get under the dash and unbolt the booster. Anyway, after I got everything back together, now the coolant temp gauge inside the truck doesn't work. Any thoughts on how to troubleshoot would be welcome. thx, mike

 

sounds like you might have knocked the wire off the sensor. the coolant temp sensor should be located on the intake manifold right behind the alternator.

 

x2. It doesn't take much to knock it off.

 

Yep, that's what I thought, also, but the temp sensor is connected, no doubt about that...how about the connection to the gauge under the dash...is that just as easy to disconnect...and where would I find it....??? I am under the impression that the actual sensor connects directly to the computer, not to the gauge...also, when I connect/disconnect the sensor, I can hear the engine idle change, so pretty sure the connection at that point is okay. thx, mike

 

sounds like you are looking at the wrong sending unit. there should be one on the drivers side of the intake that is for the computer and there should be another sending unit on the passenger side of the intake manifold for the gauge. to test the gauge you would just have to ground the single wire.
should look like this

 

Thank you, Thank you, Thank you!! I'll look for the sensor on the passenger side....sounds like the likely culprit!!! Will keep you posted. I hate these valve covers....PERIOD!!! About to go crazy w/ some form-a-gasket!!!

 

Thanks for a great answer - the picture of the sensor made it easy to find and, yes, it WAS disconnected...hooked it back up and..viola...got my temp gauge back!!!