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coolant leak

Dave WM

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I noticed a small coolant leak, had drops on bottom of oil pump (lowest point I presume). Added dye, checked after getting up to temp, and pressurized when  cold. No spurters but I did see dye evidence bottom of water pump, around the gasket, some under the pulley, and what I think is a small leak out of the timing cover where there is a galley that I presume is there to dump any leakage from the water pump holes in the timing cover.

I replaced all this stuff when I got back from my pikes peak trip and had to replace a broken TC guide. I used some sealant around the water and oil pump holes on the TC cover gasket, both sided IIRC.

Perhaps I did not use enough or the correct amount (hence the water leak on the side of the TC cover). I am 99% sure its from there, but 1% is from the water inlet housing (seems lower than that).

No matter the plan is to use NISSAN TC and water pump gaskets, new water pump, Permatex aviation gasket sealer (did not use that before). and for grins a new rad (brass/copper). The rad is because I see some blockage in the core that was not cleaned out when I had it rodded out. the brass/copper is because I prefer that over alum (Jeff I can give you back your alum since I will now have a spare for the test stand).

I will leave the front crank seal  (its a year old) alone, hope I don't regret that. I can't stand to see a leak. I have a brand new TC cover I am thinking of using, just because I have it and may as well use it. If I go that route I will have to install a new front gasket, will have to get a Nissan if I do, Darn, should have ordered that with the other Nissan gasket.....

will let you know how it goes.

'Anyone use this Permatex aviation sealant think pn is 800019?





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4 hours ago, Dave WM said:

'Anyone use this Permatex aviation sealant think pn is 800019?

It's great stuff, particularly when a paper gasket is used, just the thinnest layer is needed but on both sides.

It doesn't work so well if you use it by itself with no gasket, that has been my experience with it.

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installed the "new" rad, looked rebuilt but it was clearly OE tanks. fitment was just ok, I had to grind a bit off the bottom flanges to fit between the frame rails, there were extra welded on nuts. the bottoms did not line up that well, about 1mm two wide. Took some effort but I was able to make it work. the petcock was in the correct spot, so the hole in the bottom pan will allow access to drain. I am now waiting on delivery of my Nissan gaskets, should have been here Friday....

If this new tank leaks I think I will have to search out a good rad shop that knows how to recore, my last shop I had used in the past was something of a let down.

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new pump in, rad in, test drive no leaks around pump or rad, but I still seem to have some seepage that appears under the water inlet housing.

I figure the possibilities are

loose hose fittings

corroded inlet

leaking housing gasket

leaking from the weep hole on the timing cover.

I hope its not the last since that would require removal of the timing cover. The plan now will be to drain the coolant down and disconnect the hoses at the housing, get the alt out of the way and do a careful visual inspection to see if I can determine the exact source of the leak. I have new OE TC gaskets in case I have to go down that path.





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nope its on the side under the water inlet, above the weep hole on the pump. the TC has a weep hole that is part of a channel that surrounds the block to TC cover coolant passages. I presume the idea is of any coolant gets past the gasket, it get into that channel and weeps out. Its is directly under the water inlet.

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23 hours ago, Zed Head said:

No camera?  Used to be there'd be a video.

coming  attractions.. Actually I pressure tested this morning could hear a leak, air, top of the rad hose at the T stat housing, yep screw not very tight. Hopefully the leak I have been chasing is just a end point for a leak at the T stat housing. I know leaks can be sneaky and origins can be far from end points. So will be testing again. I did hold up my mirror to the TC weep hole and saw no dampness at all while under pressure. I have a few videos of the unboxing of the rad, but have not reviewed them yet, that is if anybody wants to see an unboxing video of a stock rad. I am very happy with the aviation Permatex sealant. will be using that for now on.

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  • 4 weeks later...

"we do it right cause we do it twice" (Mustei1)

Yesterday was removal day, today was surface prep day, I did a much better job of trying to get every remnant of old gasket material off than I did the 1st time. LOTS or scraping and solvents.

I looked at the coolant passages, it was clear the gasket/rtv I used was not doing its job. I think I may have been a contaminant on the surface as there was practically no bond between the gasket and the cover.

This time I was careful to use brake clean and not touch either the block or the cover after dousing with brake clean.

when the surfaces were dry I used a liberal amount of Permatex aviation sealer around the water passages on both surfaces. Less was used elsewhere and just a very light amount around the oil passages (did not want any squeeze out in there, besides a minor leak there is of no consequence.

I have the cover in place but not torqued. Just tapped into place on the dowel pins and bolts in just to a very light finger tight. will let it set for a couple hours and go back and torque it. I want the Permatex to have a chance to setup a bit. Not sure if that is the right thing, if not well, I am getting good at removing TC covers.

Been taking some short videos including a look at the gasket fail, will post up when done.

I was going to use my brand new TC cover but the casting on it was not as nice as the OE casting, I doubt that it would leak, but figured the old one was looking good after I did a good clean up on it. I will use a new water pump, I just don't feel like cleaning the old gasket that seems well stuck.

I know now that it was the correct call to remove the cover based on the visual inspection of the water passage joins, there was no way it was ever going to stop (corrosion would never seal it).


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  • 2 weeks later...

pretty wizz poor job on my part from the 1st time I replaced the TC cover (after the tight side chain guide failed. If you look closely you can see the green dye coolant in the weep channel.

All done, no seepage so far looking good. videos coming.




Edited by Dave WM
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