This past weekend a replaced the head gasket on my 1996 D16Y8. In the past year or so, most of the parts of the cooling system have been replaced except for the ECT sensor so I figured why not? Sprung the extra cash for the OEM when I went to the dealer for the gasket and head bolts even.

When I put everything back together, the car started up first try with no issues EXCEPT for the fact that my temp needle doesn't move at all. I re-installed the new one a couple times and no-go. Also tried the old one (I had stepped on it but the prongs were ok) and got the same result.

Upon closer inspection to the connector, I noticed it was leaving behind oil on the ECT when I would pull it off. It seems that it got some oil/coolant in it when I was taking the head off... I must have use about 1/3 can of compressed air blowing it out and kept trying to no avail.

The motor seems to run fine and the fans kicked on as well.

My questions are as follows:

Is it possible that the connector has gone bad from the oil? Will it work after it completely dries out? Should I try another ECT? How do I install a new connector if I end up having to? Does the ECT do anything other than just send the temp info to the gauge? Is it safe to drive the car other than not knowing if I'm starting to overheat?

 

There are two sensors in the end of the head underneath the distributor.

The one with two wires is the ECT, it tells the ECU how hot the engine is, it does not affect the fan* or the dash gauge.
The one with one wire is the temperature sender, it drives the dash gauge.

* the radiator fan is controlled by the thermo switch on the thermostat housing.

To test the dash gauge system, unplug and ground the sender wire from the sensor with one wire. When you turn the key on, the gauge should go all the way up to hot. Do not leave the key on and let it slam at hot. With the wire open, the gauge should stay at cold.

 

Un-*******-believable. I can take apart half of my engine bay to replace a head gasket successfully but forget to plug in something that simple. Dude, thank you for clearing that up. If only I hadn't ordered the replacement connector already... Good thing it was only 15 bucks!