Bubbles in coolant reservoir, blown head gasket? Cavitation? Something else?

Yesterday my coolant reservoir overflowed a bit at the end of a trip where temps occasionally reached 220F. I thought it was odd, but just assumed some problem with my radiator cap (6 months old). Let the engine cool down until I could get the cap off and test it, the cap tested fine. Used my vacuum filler to top off the coolant, found that system would not hold vacuum like it used to, but topped off anyway as I had left over coolant. Then pressure tested the cooling system to 16psi. Over five minute the pressure crept down to 14psi, then held there for 15 minutes. Started it up (engine still runs perfectly), Pressure started to build up immediately, even though engine was cold. After running for 5 minutes or so I noticed bubbles coming up in the coolant reservoir tank- Uh oh! Checked oil; level. Appearance, smell, and taste all normal. Smelled bubbles in coolant reservoir, no exhaust smell detected. Watched and smelled exhaust for symptoms of combusting coolant, none were present.

I suspect my head bolts/gasket have loosened up enough for combustion gasses to get pushed by the gasket on combustion (190,000 on engine, 170,000 of history unknowable), any other time the system holds pressure (seems like a cavitation hole would leak down continuously). What do the Oilburners think?

I think I will be pulling the heads, maybe even the entire engine so I can attack the oil cooler as well. Given the mileage I would like to get the heads rebuilt (or buy some rebuilt heads). Obviously I will need head bolts. Any advice/help running down these items would be greatly appreciated.

Thanks.

Kirk
https://youtu.be/w6uiZLjyjm0

https://youtu.be/udxgKixoGvE

I'd be guessing a HG

That much bubbling would have to be headgaskets. We'll leave cavitation out of this conversation for now. Lol

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I am getting ready to pull the heads on my truck (small coolant leak at rear of left head), when the weather eventually warms up a bit. I intend to do an oil cooler reseal after the left head is off. Should have good access to the oil cooler at that point without having to remove the engine. Of course, if you pull the engine the HG change and oil cooler reseal will all be easier.

So my plan at this point is to go ahead and pull the engine. Once it's out I think I will do a leak down test on each cylinder with the piston at TDC then again at bottom (rockers off to ensure closed valves). the hope is to isolate where my leak is & whether it is a head gasket, warp, or crack. Or a block problem. Sound reasonable?

MTKirk said:

So my plan at this point is to go ahead and pull the engine. Once it's out I think I will do a leak down test on each cylinder with the piston at TDC then again at bottom (rockers off to ensure closed valves). the hope is to isolate where my leak is & whether it is a head gasket, warp, or crack. Or a block problem. Sound reasonable?

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Well thats a lot of work for a leak down which could be done in the vehicle...however it is your truck to do as you wish.

Yes it should provide usefull info to wkrk from too

JM7.3CW

riotwarrior said:

Well thats a lot of work for a leak down which could be done in the vehicle...however it is your truck to do as you wish.

Yes it should provide usefull info to wkrk from too

JM7.3CW

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Well I'm 99.9% sure I am going to need at least head gaskets. While that could be done in the truck (and certainly the leak-down) I have a nice shop to work in, with a 2-ton chain hoist and a massive engine stand, so I think it will turn out to be almost the same amount of work. And it sure is a lot more comfy working on an engine in a stand than in the truck.

MTKirk said:

it sure is a lot more comfy working on an engine in a stand than in the truck.

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yeah, but it's a helluva lot of un-needed work to yank the engine and put it back in unless you're going inside it!

http://www.oilburners.net/forums/sh...-bubbler-Bubbles-in-the-coolant-overflow-tank

Looks EXACTLY like my leaking head gasket I had last fall. The combustion-gas leak test didn't detect anything on mine.

I pulled the engine because I already had studs in. I think I didn't get enough lube on the studs when I first installed them so I didn't get an even torque. When I put in the new gaskets I used lots of lube and I have not had any issues since.

jwalterus said:

yeah, but it's a helluva lot of un-needed work to yank the engine and put it back in unless you're going inside it!

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I hear ya, I just don't think there's any solution for my issue that won't involve at least removing the heads. Do you?

jhenegh said:

http://www.oilburners.net/forums/sh...-bubbler-Bubbles-in-the-coolant-overflow-tank

Looks EXACTLY like my leaking head gasket I had last fall. The combustion-gas leak test didn't detect anything on mine.

I pulled the engine because I already had studs in. I think I didn't get enough lube on the studs when I first installed them so I didn't get an even torque. When I put in the new gaskets I used lots of lube and I have not had any issues since.

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Well sheeeeeit! Looks like you all-ready got this thing all figured out! Looked over your thread, watching the video it was like I was watching my own coolant tank. I feel much better now about my plan of attack. I'm going to put in studs (with plenty of lube!), use a fel-pro gasket- what brand of copper coat did you use & why? I'm also going to have my machine shop give the heads a looking over and a magna-flux. Hopefully they'll loan me a straight edge to check the block deck for level as well (in a pinch I could take it to them, but that would be a pain).

Anyway thanks, this forum delivers again!

pull the engine for head gaskets, wow that's a lot of hours of work . I remember doing idi headgaskets in the 80s in Eseries and we did them in chassis. wasn't easy but was doable with some plastic ties and mechanics wire. in a PU headgaskets aren't bad at all, even if you are doing studs.

its your truck, if you had internal issues it might be a good idea . I guess working in the trade for to many years has taught me to not do any more labour than necessary, especially when its on your own stuff and not getting paid for it.

Meh, doesn't take that long to pull the engine. Definitely a lot more working room.
Good time to reseal everything anyways.

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compressionignitionrules said:

pull the engine for head gaskets, wow that's a lot of hours of work . I remember doing idi headgaskets in the 80s in Eseries and we did them in chassis. wasn't easy but was doable with some plastic ties and mechanics wire. in a PU headgaskets aren't bad at all, even if you are doing studs.

its your truck, if you had internal issues it might be a good idea . I guess working in the trade for to many years has taught me to not do any more labour than necessary, especially when its on your own stuff and not getting paid for it.

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Given that I've just done the flywheel & clutch the bell housing bolts and mount holes have been cleaned and anti-sieze applied, also the stock fan has been removed, replaced with electric fans that come off quick, radiator removal is a breeze, AC compressor is new and bolts were cleaned & antisiezed. The engine mounts are the only thing I haven't had off. I think I'm looking at about two hours extra to pull the engine. To me it's well worth the extra labor to minimize my time crouched over the engine compartment, especially with my fifty-something body and eyesight.

MTKirk said:

Given that I've just done the flywheel & clutch the bell housing bolts and mount holes have been cleaned and anti-sieze applied, also the stock fan has been removed, replaced with electric fans that come off quick, radiator removal is a breeze, AC compressor is new and bolts were cleaned & antisiezed. The engine mounts are the only thing I haven't had off. I think I'm looking at about two hours extra to pull the engine. To me it's well worth the extra labor to minimize my time crouched over the engine compartment, especially with my fifty-something body and eyesight.

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ahh you already have it prepped for removal. hey 50 is the new 30