Can you replace the factory head temp sensor with the engine still in the car?

Thanks

It can be done. There are special sockets made for this that have a slot for the wire. I use a deep six point socket that has the face ground flush so it grabs as much of the sensor as possible. To clear the wire use an extension that has one corner ground off. Thread the wire up thru the socket then put the extension in.

Yes. 13mm very deep socket. grind one corner off a short extension for the wire to pass thru.

I assume I have to remove that side of the engine tin?

No. Just stick your customized tool down into the hole and remove it.

When you re-install, thread it in by hand to avoid cross-threading. If you do that you will be removing the engine.

Ok.. I didn't realize there was an access hole for the sensor. Looks like its an easy job. Just have to remove the intake runners.

Thx

You don't even have to remove the intake runners (that can be a PITA), just work around them. I've done it many times before...

Most IMPORTANT....put just a couple drops of super glue on the copper washer and attach to the sensor so you don't drop it down into the engine tin.

slot for wire...worked like a charm....

so I am guessing you have one copper washer in there since you say it like that

nah...just glad someone else point that out before I changed mine. Made sure I had some glue on hand for the job. Not a typical item in the tool box.

Don't know how else you'd get it on there (with the washer) with the engine in the car...

yep, this is what I use.

This works too (circa 1981 or 1982):

Be careful not to cross thread the sensor threads. The PO did this on my motor and it would intermitantly loose contact and mess up the mixture. I had to tap and coil new threads in to make it work! PITA

I'll take credit for that tip, I think I'm the source

The copper washer is important for good heat transfer from the head to the sensor. Hard to understand why they didn't make it captive, considering how it's installed.

BTW, in another thread, I reported that for VW applications, there is a spacer that you can put between the CHT and the head. It's about 3/4" long. The idea is that it delays the sensor from being heated up initially when the motor is cold, so that the mixture stays richer for a longer time. Might be an interesting way to fix some warm-up issues.