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Blacksailsdive 06-09-2021 07:49 PM

Losing alot of coolant out of cats!
So long story short I got a free 4.7 GC from a buddy that needed a bunch of work, at 190k miles. I just finished installing new head gaskets after getting freshly machined heads for it. Everything was cleaned and prepped, torqued down via the prescribed pattern and specs. Also used new TTY headbolts.

Jeep will start and everything sounds great, minus the streams of coolant out of the cats, and fan working hard.

Before the new heads it ran rough and misfired on #8 with a hefty oil leak.

This will be the 3rd set of new head gaskets and head bolts ive installed on the jeep this week in trying to fix the sealing issue 😡 any ideas gents???

underscore 06-09-2021 07:54 PM

Was the block decked?

Golden-Arm 06-09-2021 07:57 PM

if you're seeing coolant coming out of the cats, then you must have holes in them. crack in the block? sealant on bolts/studs that run into water jackets? again, coolant out of cats? why not pressure test the cooling system, and see if it's leaking? the parts stores loan testers out, if you don't have one. coolant coming out of cats? i just can't get my head around this one.

Blacksailsdive 06-09-2021 08:07 PM

Im assuming the heads were, ordered them from a reputable machine shop. Well its def leaking so I can probably skip the leak down test. There are small pin holes before and after the cats thats where the coolant is coming out of, im assuming flowing right down the inside of the headers/Y-pipe.

Blacksailsdive 06-10-2021 09:21 AM

Wanted to make sure I worded everything correctly, the coolant leak is heavy and def coming out of the exhaust manifold, the one thing I did notice before installing the new heads was that the bottom of the valves (circular part) were not completely flush against the head surface like the old heads that I pulled off. Would this allow a passage for coolant to enter the headers? If so do I need to adjust the valves?

Double E 06-10-2021 11:53 AM

No. That valve oddity is not letting the coolant in. The valve grinding job may have left a lip on the valve and it's actually fine but it is a curious thing to have observed. Got pics? Are the valves the original or new?

I support the remove/replace process for the heads to the block is being done incorrectly (bolt in a water jacket is not being sealed properly or a passageway is not being sealed due to incorrect HG placement, a crack in a water jacket is going undiagnosed or something else is going on.

For something else...water is actually a byproduct of combustion. Are you 100% certain this is coolant and not water? What makes you certain? Color/taste, chem analysis?
Be certain before you tear into this thing again.

Delta0 06-11-2021 01:12 AM

My money says there's a leak through the aluminium into the exhaust between valve and manifold.

Bigrigr 06-11-2021 08:17 PM

Are you sure you dont just have coolant built up in the cats from the original head gasket leak? I have seen bad head gaskets or cracked heads that pushed coolant into the exhaust, and then it poured out of the exhaust when the repair was performed because the exhaust was pushing it out. Is the coolant level dropping in the engine? Did you perform a quality bleed procedure when you first filled the coolant and started it?

Blacksailsdive 06-12-2021 08:48 AM

Brigrig, thats def a possibility ill dig a little deeper but the sheer volume of coolant coming out makes me think more the new heads or like others have said something isnt quite sealed correctly. Im out of town right now but will update with pictures to better show what is going on, but the coolant is coming out with some force, more so if the engine is running but it will start flowing with every rotation of the starter as well.

Delta0 06-13-2021 03:03 AM

If it's a historical leak as you suggest Bigrigr how long should Blacksailsdive leave his motor ticking over for to clear it.

If it ticking over doesn't clear it, and I hope it does: -

Your exhaust valves are some distance from your head gasket.
Some distance sideways, and some distance above.

How on earth is coolant going to jump sideways and upwards to get into your exhaust without occasionally water-locking your engine?

On the other hand, what's the argument against water leaking from the head into the duct that takes exhaust gases to the exhaust manifold when your engine isn't turning?

Golden-Arm 06-13-2021 09:27 AM

pressurize the cooling system, and find the leak. you might have to pull the exhaust manifold(s), valve cover(s) to find it. just because you "know it's leaking" doesn't mean you don't test it. if it doesn't leak without pressure, how will you ever find it? i'd be checking my oil for water in it, and as mentioned above, water leaking into the manifold could run the other direction, and hydro-lock a cylinder. pressure testing is free. replacing a bent rod, maybe not as free......

WJ60 06-13-2021 10:10 AM

Could I back the boat up for a second? Before the new heads were installed was the coolant issue at the cats there, or just the oil leak?

Blacksailsdive 06-13-2021 11:03 AM

So before the new heads were installed the issue was a misfire on #8 due to the rocker coming off frequently as well as one of the valves on #8 being on its way to dropping the seat. One of the reasons im sort of questioning the new heads?

Blacksailsdive 06-13-2021 11:04 AM

As well as the oil leak ^^^

WJ60 06-13-2021 12:40 PM

I really question the new heads now.

The time now is 03:11 AM.

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