Overheating 69
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Heel & Toe
Joined: Dec 2025
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Overheating 69
69 SBC. Had a shop install headers and side pipes. They removed the temp sending unit from the block cause it hit the header and moved it to the intake manifold. Since then the temp gauge runs hot, 230. They used a temp gun and showed me it was running a lot lower so I replaced the temp sensor but no change. I’m assuming they used a standard plug on the block. No water leaks. Thoughts?
1967 Pedal Car Champion
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69 SBC. Had a shop install headers and side pipes. They removed the temp sending unit from the block cause it hit the header and moved it to the intake manifold. Since then the temp gauge runs hot, 230. They used a temp gun and showed me it was running a lot lower so I replaced the temp sensor but no change. I’m assuming they used a standard plug on the block. No water leaks. Thoughts?
Did you use anything on the threads as sealant?
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Sealant on the threads won't hurt a thing. That's a myth.
If they didn't change to a different sender. Then trapped air does sound like a possibility.
If they didn't change to a different sender. Then trapped air does sound like a possibility.
1967 Pedal Car Champion
Joined: Mar 2020
Posts: 9,147
Likes: 4,258
From: US-PNW
Race Director
Joined: Nov 2006
Posts: 13,282
Likes: 7,863
From: Sunshine Coast, Queensland, Australia
2025 C3 of the Year Finalist - Modified
2024 C3 of the Year Finalist- Modified
2022 C3 of the Year Finalist - Modified
Cruise-In VIII Veteran
Teflon tape or sealant will fill in the low spots. But will definitely be sheared away in the high spots. It's a tapered thread. It's how it works.
Brand new sensors come with sealant pre applied by the factory's.
Remove any temp or oil pressure sensor from any engine. You'll see what I'm talking about.
Brand new sensors come with sealant pre applied by the factory's.
Remove any temp or oil pressure sensor from any engine. You'll see what I'm talking about.
1967 Pedal Car Champion
Joined: Mar 2020
Posts: 9,147
Likes: 4,258
From: US-PNW
Teflon tape or sealant will fill in the low spots. But will definitely be sheared away in the high spots. It's a tapered thread. It's how it works.
Brand new sensors come with sealant pre applied by the factory's.
Remove any temp or oil pressure sensor from any engine. You'll see what I'm talking about.
Brand new sensors come with sealant pre applied by the factory's.
Remove any temp or oil pressure sensor from any engine. You'll see what I'm talking about.
Melting Slicks
Joined: Apr 2021
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From: Minnesota
I agree, tightening it should give you more than enough metal on metal contact to get good continuity, but it’s easy enough you can try it without as a sanity check.
Last edited by Piersonpie; Today at 12:16 AM.
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Some people over do it when applying thread tape or sealant, so when the fitting is snugged and tightened, in theory, there could be no metal to metal contact.
More tape or sealant isn’t a good thing.
It only takes about two wraps around the fastener and anymore is just overkill.
When I add tape, I pull it tight so the threads high points show through the tape.
If you have a concern, remove the fitting and you’ll be able to see if there was metal to metal contact.
Clean it up, add a couple wraps of sealant tape and reinstall it.
Use the correct tape.
White is for water and coolant is not water.
Many people believe the only place a temp gauge should be installed is in the head, not the intake.
Old school temp gauges were installed in the cylinder head but that’s changed to the intakes.
More tape or sealant isn’t a good thing.
It only takes about two wraps around the fastener and anymore is just overkill.
When I add tape, I pull it tight so the threads high points show through the tape.
If you have a concern, remove the fitting and you’ll be able to see if there was metal to metal contact.
Clean it up, add a couple wraps of sealant tape and reinstall it.
Use the correct tape.
White is for water and coolant is not water.
Many people believe the only place a temp gauge should be installed is in the head, not the intake.
Old school temp gauges were installed in the cylinder head but that’s changed to the intakes.