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360 leaks water from lower timing cover bolt

Posted By: 70FJ5383

360 leaks water from lower timing cover bolt - 12/05/17 07:47 AM

Bottom bolt on the left hand side of the timing cover. Just above the oil pan. It just started leaking the other day, antifreeze from around that bolt or maybe the gasket but I think it’s around the bolt. Does it go through into the water jacket? If so will silicone fix it?
Posted By: Porter67

Re: 360 leaks water from lower timing cover bolt - 12/05/17 08:52 AM

Yes it goes through, id just drain it while its hot so it self dries and use a good sealer on the bolt. I like the dark thick airplane gasket goop or simple rtv.

But it seems you know the deal already.
Posted By: 70FJ5383

Re: 360 leaks water from lower timing cover bolt - 12/05/17 11:35 AM

Wasn’t sure. And if rtv was ok.
Thanks
Posted By: Supercuda

Re: 360 leaks water from lower timing cover bolt - 12/05/17 02:54 PM

I would not use RTV, Teflon tape is better. It will seal and it will keep the bolt from corroding itself solid tot he block.
Posted By: RapidRobert

Re: 360 leaks water from lower timing cover bolt - 12/05/17 03:11 PM

Quote:
I would not use RTV,
X2, I would use some thick cement like permatex #2 or Indian head shellac.
Posted By: a12rag

Re: 360 leaks water from lower timing cover bolt - 12/05/17 04:56 PM

Originally Posted By Supercuda
I would not use RTV, Teflon tape is better. It will seal and it will keep the bolt from corroding itself solid tot he block.


X2 . . . teflon tape the bolt . . .
Posted By: dogdays

Re: 360 leaks water from lower timing cover bolt - 12/05/17 09:12 PM

RTV won't stick to a wet surface. The non-hardening Permatex (stinky, in a small tube)is good and really all old timers used back in the day. Gasket shellac isn't meant for that use.
Teflon tape or paste will work. Hylomar blue works. FelPro TIGHT is both a sealer and locker.

Or you could put a little stop-leak in the radiator and it'll stop leaking, without disassembly.

R.

PS: I vote for Stop-leak. BTW, that isn't the worst thing you can do from the front of the engine. It is possible to use a bolt long enough that it penetrates the cylinder wall.
Posted By: qwkmopardan

Re: 360 leaks water from lower timing cover bolt - 12/06/17 04:24 AM

The lowest bolt does not go through to water. the second from the bottom is the one that is through to coolant. Probably running down and looks like it is dripping from the lowest bolt. Same thing on other side, except that bolt is behind the water pump.
Posted By: Magnum

Re: 360 leaks water from lower timing cover bolt - 12/06/17 04:35 AM

I prefer to seal straight threads with silicone.
Posted By: dvw

Re: 360 leaks water from lower timing cover bolt - 12/06/17 12:18 PM

Liquid Teflon sealer will seal threads with no issue. Brand X uses it on head bolts that go into the water jacket. There may be a bigger issue. The timing cover may be corroded or the timing cover gasket split. This can allow coolant to migrate from the water pump passage out the bolt. It may also allow coolant to get into the oil.
Doug
Posted By: RapidRobert

Re: 360 leaks water from lower timing cover bolt - 12/06/17 04:58 PM

Agreed (on the leak potentially being nearby). I would drain the coolant & screw in an NPT "tank valve" (less than $3 at O'reillys) into the cooling temp sensor port at the top rear of the block & with shop air pump it up to 15 lbs & see if it holds. You can spray a soapy water solution around potential areas to see if it starts to bubble (for external leaks) & there is a "bubble up" (iirc) solution that reportedly bubbles more readily but the dish soap in some water has worked for me. EDIT on second thought I would pump it up to just 10 for a start.

Attached picture SAM_0604.JPG
Posted By: Joesixpack

Re: 360 leaks water from lower timing cover bolt - 12/08/17 06:12 PM

Have same problem with bolt above timing tab, went to tighten it and it just spins....threads in timing cover must be stripped..has anyone put a heli coil in the timing cover still on the engine before or do i have to remove it ?
Posted By: Paul_Fancsali

Re: 360 leaks water from lower timing cover bolt - 12/08/17 06:47 PM

Drain block and coat bolt with sealer let it set overnight and then add anti freeze Do do this if you cannot maintain at least 50+ degree if sealer is silicone
Posted By: cudaman1969

Re: 360 leaks water from lower timing cover bolt - 12/09/17 12:40 AM

One more thing to think about, the cover is aluminum, block cast iron. Electrolysis. Over time the cover corrodes, I've replaced a few because of this problem. What looks like a leak around a bolt turns out to be a tc cover. A bad sign? Moisture in the oil. Look at it good, water will travel far from where it actually leaks. Other than a messed up gasket, bad cover is the only time I had a leak.
Posted By: RapidRobert

Re: 360 leaks water from lower timing cover bolt - 12/09/17 01:31 AM

Originally Posted By Joesixpack
Have same problem with bolt above timing tab, went to tighten it
Which bolt (hole) in particular is that?
Posted By: Joesixpack

Re: 360 leaks water from lower timing cover bolt - 12/10/17 05:51 PM

lower right hand corner of water pump. attaches water pump to timing cover.
Posted By: RapidRobert

Re: 360 leaks water from lower timing cover bolt - 12/12/17 12:22 AM

those lower threads on the aluminum timing cover are a weak 11/16" deep & open on the back side & go directly into the timing chain area/eng oil & it uses a 3/8 bolt so I'm thinking if you could block the very back with something fairly firm just to temporarily plug the rear end of that passage for your work then drill/tap a good amount of the threads then carefully/lightly blow the chips out the front (the critical part) & I would use brake kleen as opposed to shop air & either helicoil or just drill/metric tap to the next larger metric size/use a metric bolt. Use grease on the tap to catch alot of debris. EDIT Another option might be to permanently JB weld a stud in there
Posted By: Joesixpack

Re: 360 leaks water from lower timing cover bolt - 12/14/17 01:55 AM

Yea i figured as much, just bought a used timing cover, will heli coil all the threads in it first and just replace the cover.
Posted By: RapidRobert

Re: 360 leaks water from lower timing cover bolt - 12/17/17 04:52 PM

I wouldn't think you would need to go to all that trouble (helicoiling undamaged threads). I think the one thread just went bad (they are aluminum) & after this you will be OK. Just me I'd clean em (& the bolts) & use some sealer & call it good.
Posted By: Supercuda

Re: 360 leaks water from lower timing cover bolt - 12/17/17 05:30 PM

Putting in helicoils in a timing cover on the bench isn't a lot of effort. doing it while the timing cover is installed in the vehicle is another story.
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