Thread sealant

[johninct]

I am doing a water pump and need a thread sealant for the bolts that go into the antifreeze. Anything special to use? I was going to use Gasolia or some other pipe thread sealants I have around. Thanks.

 

[JoeMcGov]

I always use a gasket type maker/sealer such as Permatex Anaerobic Gasket Maker.

 

[LS6 Tommy]

Permatex #3 Aviation Form A Gasket.

Tommy

 

[rustyjames]

Permatex #2 also works well.

 

[snyder]

Gasoila works fine,

 

[jsaw]

Teflon paste works for me.

 

[GRivera]

Permatex water pump and thermostat gasket sealant
https://www.permatex.com/products/g...ex-water-pump-thermostat-rtv-silicone-gasket/

 

[LS6 Tommy]

Teflon paste works for me.

Just FYI, TFE Paste is not a sealant. It's a lubricant and it's not designed to be used for machine threads like water pump bolts, it's only for mating pipe threads.

Tommy

 

[428PI]

Teflon paste. Not had a problem with this sort of thing despite what LS6 Tommy says. I've been a mechanic for over 40 years.

 

[LS6 Tommy]

Sounds like the guy that has had PVC air lines for 40 years without a problem.

Seriously, do it however you see fit. I'm just providing info...

Tommy

 

[Tinkerman66]

Just FYI, TFE Paste is not a sealant. It's a lubricant and it's not designed to be used for machine threads like water pump bolts, it's only for mating pipe threads.

Tommy

"It's only used for mating pipe threads"

To seal them, no?

 

[rlitman]

Just FYI, TFE Paste is not a sealant. It's a lubricant and it's not designed to be used for machine threads like water pump bolts, it's only for mating pipe threads.

Tommy

There are all sorts of teflon pastes. Ones meant for mating pipe threads are indeed thread sealants for NPT type conical tapering threads (they're non-curing sealants that are not meant to fill the large gaps of parallel threads).

Now about your water pump bolts. Those don't have conical tapering threads. Also the threads don't form the seal. So no amount of any sort of paste on the threads will help with the seal. Be it teflon paste, or form-a-gasket (which I don't like on threads), etc.

Either the threaded hole is blind tapped and doesn't open into the water jacket, or there should be a sealing washer under the bolt head, or perhaps the blind hole is under an ear that projects outside of the gasket's sealing area in which case nothing is wet.

I like to use a teflon paste pipe dope on the wetted threads anyway, as it prevents seizing, and is less likely to wash out than a metallic anti-seize (which I would use on the dry threads in the third case I mentioned). Plus you shouldn't be introducing foreign metals (metallic anti-seize) into the antifreeze anyway.

 

[HenryAZ]

Loctite 542, for sealing straight bolt threads against fuel, oil, coolants and hydraulic fluids.

 

[Falcon67]

Not a damn thing here. I used stainless bolts, no sealant. If I was to use a sealant, I'd lean to Permatex #2.

 

[redmondjp]

I thoroughly degrease and dry the threads on both sides and apply a bit of Permatex Ultra-Gray RTV to the threads before installation - only on those bolt holes that go directly into coolant passages. On ones that go into engine oil, I use Permatex #2.

 

[LS6 Tommy]

"It's only used for mating pipe threads"

To seal them, no?

There are all sorts of teflon pastes. Ones meant for mating pipe threads are indeed thread sealants for NPT type conical tapering threads (they're non-curing sealants that are not meant to fill the large gaps of parallel threads).

Now about your water pump bolts. Those don't have conical tapering threads. Also the threads don't form the seal. So no amount of any sort of paste on the threads will help with the seal. Be it teflon paste, or form-a-gasket (which I don't like on threads), etc.

Actually, straight PTFE pastes and tapes are not sealants at all. Most "pipe dopes" are not. They are lubricants that allow a proper interference fit on tapered (pipe) threads. There are pipe thread sealants that contain PTFE, so it can be confusing.

Permatex #3 Aviation form-a-gasket is specifically listed for use on "screw threads" like water pump, intake manifold or cylinder head bolts as a sealant and is approved as such for both automotive and aviation use.




Tommy

 

[38Chevy454]

Permatex #2 for me over many years of similar application.

 

[clubairth]

Another internet expert.

Perhaps reading a label might point to the correct answer?
Yes it's a sealant.

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