Can I get a threaded thermostat housing?

oz

Founding Member
Jun 29, 2000
1,071
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38
Plymouth, MI
I'm in the process of putting gauges in my '91 and want to put my temperature sending unit in the thermostat housing. My housing does not have the NPT threaded hole with plug that my '69 has. I would use one from an earlier car but the hose outlet angle is different (45 degrees older, 90 degrees newer I think).

Does anyone sell a housing with the threaded hole for late model 302's?

<OR>

Has anyone taken off the stock one and drilled and threaded it (the one in the car has a big dimple in the casting at the right place that was never drilled and tapped so it may not be too hard)?

Thanks.
 
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Yeah they sell them with a pre drilled hole, its chrome and the last time I checked to was $25 at 50resto.com.

I drilled and threaded mine with a 9/16 drill bit and a 3/8 npt tap bit, it was easy. You need a 1/2 in chuck on your drill for the 9/16 drill bit though.


Oh yeah if you put the temp sending unit in the thermo housing, the gauge wont read untill the thermo opens because the sender isnt in the engine. I would know, I have an aftermarket gauge in the thermo hole and the stock gauge in the stock place.
 
The parts store sells a cast housing for 10 bucks. It has a 3/8" NPT hole. Paint it so it doesnt look rusty.

As I recall, the chrome housings were actually discontinued because they are so prone to leaking.

I do agree about using the housing for your stock gauge (because it's on the wrong side of the t-stat. If the stat sticks closed, your gauge will be retarded). Put the new gauge's sender in the stock location.

Good luck.
 
Autozone has one for about 10 bucks. I bought one and realized that it was cast iron(not fond of chrome either) so I just drilled and tapped mine after borrowing a NPT tap. Works like a charm.
Kevin
 
Autozone has one for about 10 bucks. I bought one and realized that it was cast iron

More likely it's cast aluminum........

Nope, its cast iron, I used to work at an Autozone a while back and it was poorly made. It had a hole trying to make its way through the housing and it looked like it was gonna leak out of the box, I told the customer to go to the junkyard and he agreed.

Drill and tap it like tmoss says.
 
Alternate placement for a temp gauge sender: Use the heater feed that comes off the intake manifold. Cut the rubber hose that connects the manifold water feed to the heater and splice in a tee adapter for the temp gauge sender. Be sure to use the same water feed line as the ECT sensor. That way you will get the most accurate temp readings.

Tee adapter info:
Make a pilgrimage to your local hardware or home supply center and get some copper pipe and a tee that fits the temp gauge sender. Solder two pieces of copper pipe onto a copper pipe tee with threads in the tee part. Find the correct brass fitting to match the temp sender threads to the tee fitting.

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Maybe you guys got bad cast housings from the parts store. As I mentioned, it's what I used for the stock sender on the '94. I've had numerous PM's about it and quite a few other folks (most 94-95's dont have a dead port on the back of the intake) have used the housing with no issues.

It's the easiest and cheapest route.
 
Well I got a casting from NAPA, painted it and installed it. I fired up the car and let it warm up yesterday to see if anything leaked. Nothing I did leaked but the CASTING has a super tiny leak! It's right on top next to the temperature probe. When the car warmed up (and the cooling system was pressurized) I watched a tiny drop of water form on the casting.
So now my question is, can such a tiny hole be sealed or do I have to remove this and replace it? I waited until the car was cool and smeared some RTV over the area but I don't consider this a permanant fix. What about cooling system sealers? I know I should get another one but am looking for a reason not to go through the hassle of doing the work :rolleyes: