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Discussion Starter · #1 ·
So my radiator has developed a slight leak in the top plastic section. Am replacing with OEM cuz why not, this one got me 15 years and 145,000 miles so hopefully the next one does too.


Am also replacing all the other stuff; water pump, thermostat, hoses, etc.


My question is concerning the gaskets for thermostat housing and water pump: Should I use RTV? maybe around the bolt holes? Everywhere? None at all?


TIA
 

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Any warning signs on that Radiator blowout?

There is no suggestion of RTV in the FSM. However, using RTV, specifically "Permatex Gray Water Pump & Thermostat Housing Gasket Maker", won't hurt anything if used properly (Thin layer on Block Surface & Thin Layer on Water Pump Surface). I would actually recommend this RTV for the Thermostat Housing as it is much more prone to leaking than the Water Pump. It is only fastened with two 5/16-18 Bolts and can be stressed by the Upper Radiator Hose. All blocks are a little different though, it's up to you, no big deal either way.

For the mounting bolts, it is common practice to use a PFTE Thread Sealant on the threads of any fastener that protrudes into a Water Jacket. Coolant can find its way through the threads and leak from the mounting holes. In the picture provided, the one bolt that goes into the water jacket is labeled #5. It is the bolt directly to the left of the inlet tube.

Also, Thread Sealant or Teflon Tape is mentioned in the FSM for the Inlet Tube. Be sure to clean and hose down your accessory drive pulleys before reinstalling the belt to prevent the common post water pump belt chirp.
 

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As the factory did, use gaskets throughout the cooling system. RTV just isn't needed and it makes repairs/replacements far more difficult. It doesn't take much to seal a cooling system component, I have even had a leak-free emergency trail repair using a gasket cut from a MRE cardboard box.
 

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Discussion Starter · #5 ·
Mattaeus- Excellent info, exactly what I was looking for. It was strange when it happened, had been doing some minor wheeling, sand, streams, couple small hills. Had just finished pulling out a stuck quad and sitting at idle waiting. Temps were fine and all of a sudden it just blew. No idea why.


-Thanks for the great response
 

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Agree with Jerry. Dont use RTV. Use the supplied gasket that comes with your new parts. Make sure the surface of the block is clean, carefully remove the old gasket with a razor, wire brush, etc...It needs to be spotless. The smallest piece of debris or leftover material will cause a leak.
 

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Mattaeus- Excellent info, exactly what I was looking for. It was strange when it happened, had been doing some minor wheeling, sand, streams, couple small hills. Had just finished pulling out a stuck quad and sitting at idle waiting. Temps were fine and all of a sudden it just blew. No idea why.


-Thanks for the great response
My first thought is that you may have blown a head gasket. This will allow hot exhaust gas into the cooling system over pressurizing it.
Not saying for sure this is what happened but be sure to at least check it.
 

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Discussion Starter · #8 ·
My first thought is that you may have blown a head gasket. This will allow hot exhaust gas into the cooling system over pressurizing it.
Not saying for sure this is what happened but be sure to at least check it.



Was able to drive it from the tow truck into my garage. It started fine and was running for about 2 minutes. Didn't notice any roughness or anything that felt like a cylinder not firing. I'll do a compression test before putting the new rad on. Tks
 

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Was able to drive it from the tow truck into my garage. It started fine and was running for about 2 minutes. Didn't notice any roughness or anything that felt like a cylinder not firing. I'll do a compression test before putting the new rad on. Tks
A compression test may not show a blown head gasket if the issue only presents once the engine is hot.

You will want to check for exhaust gas in the cooling system.

https://www.napaonline.com/en/p/BK_7001006
 
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