Reproduction Parts for 1916-1964 Chevrolet Passenger Cars & 1918-1987 Chevrolet & GMC Trucks



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Joined: Jun 2020
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Grease Monkey
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Grease Monkey
Joined: Jun 2020
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Does anyone have any tips on getting the temperature probe to seal where it seats in the head ? The tapered seat in the head looks pitted, so I don't expect a metal to metal seal to keep coolant from leaking out.
Kevin

Filling Station - Chevrolet & GMC Reproduction Parts


Filling Station


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I use both Teflon tape and pipe dope. You are correct that metal-to-metal will not seal (even if it is not pitted).

I clean the external threads with a wire brush I keep on one end of my grinder. Then I use a small diameter wire brush on my Drexel to clean the internal threads.


Rusty

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Backyard Mechanic
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I use an o ring just underneath the probe as i insert it in the head fitting. Even though mine is worn there is a small ridge inside the cylinder block fitting that seats the O ring. I tighten the nut on the probe only slightly as my probe ridge under the nut is a bit small. After filling with water I only tighten sufficiently to stop any leak.

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I can definitely say that pipe dope and Teflon tape would be of no use on my 38. That is because the hold down collar on the probe has two flat sides. The o ring was the solution for me and it is much better than the original design


My 1951 1 Ton is now on the road! My 38 Master 4 Door is also now on the road .
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Grease Monkey
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Grease Monkey
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I should have mentioned the probe fitting is square, so the threads have 4 flat spots. The probe taper is at most 1/8" wide and the only place a seal will be effective. How long will an O ring last in a heated location ?
Kevin

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An O ring will just grind up. A copper crush washer with a little sealant on each sde would be better.


Gene Schneider
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The oring I believe if it goes under the flange of the probe will work if tightened carefully. I agree it will distort if the nut is in contact with it when tightening.


Steve D
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My 46 has the original heat gauge and probe/bulb in it.
I used a wire brush to carefully clean the flange at the top of the probe/bulb (the bottom side of which does all of the sealing against bottom of the hole in the cylinder head), and the bottom edge and threads of the nut.
Then I pushed a battery cable cleaning brush down in the hole in the head and spun it around to clean the sealing surface in the head.
I brushed a good coat of Permatex copper anti seize compound on the flange on the probe/bulb, and some on the threads on the nut.
Then I just put it together with nothing else added.
Hasn't leaked a drop since. :-)


Ole S Olson
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The busing in my 38 had a little nick out of the seat. This damaged the bottom of the probe. I also discovered that finding another temperature gauge would be difficult. They actually sell that bushing new. My troubles grew worse when I went to a sealed system with the new rad,


My 1951 1 Ton is now on the road! My 38 Master 4 Door is also now on the road .

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