Anyone know what the thread size and pitch is of the coolant plug on the lower front part of the intake manifold?
I want to add a coolant temp gauge. VDO offers a wide selection of different sized sensors and I would like to order one that will just screw in without having to re-thread or tap anything.
95 D1, Thanks

 

I was just looking up my post to find out a couple days ago and couldn't find it. I do know it is SAE thread.

 

So, I finally got around to removing that coolant plug, and yes, it's SAE.
3/4-16NF... or UNF, if you prefer, same either way. Also, this is not a tapered pipe thread, it's standard bolt thread.

 

Good deal. Thanks for posting.

 

For future reference, in case someone else searches...
In a PDF download for VDO sensors, there is a 250 degree 3/4-16NF temp sensor listed... but, it's marked as being phased out. Searching on line, that sensor is still available, but it's fifty dollars. How long they can still be found is anyone's guess.
I've never had a VDO temperature sensor fail... but I would sure hate to have one fail and find there is no replacement to be found.
IMHO, best bet, if you plan on keeping your truck, just drill and tap the stock coolant plug. A 1/8-27NPT sensor is twelve dollars and easy to locate.

I already had a VDO gauge, so I never bothered to check other manufactures of aftermarket gauges. There may well be another senor by someone else that will fit the existing hole size.

 

Anyone find a supplier for adapters in this size? I need to put a GM temp switch in there and think its line 1/2" npt

 

I used two adapters, one from 3/4-16 to something, and that something to 1/8 NPT for my sender. Probably what you will have to do.

 

This might work for you > http://www.summitracing.com/parts/nvu-99004-40

 

1/2" npt is large. GM uses screw in heater hose fittings on some of their stuff that is 1/2"-14npt.
1/2" npt is larger in diameter than the 3/4-16nf hole in the intake. You could just tap the intake to that size and not use an adapter.

 

Maybe its 3/8 npt then , standard GM one wire switch late 80s early 90s