I think my head gasket failed

[mgFray]

I've got a 6.5L GEP in my HMMWV. Last Saturday I dove 2 miles into town, 2 miles back and right when I pulled into the driveway she started puking coolant all over the ground. By the time I realized what had happened, the temp gauge when from 210 to 240+. I shut it down right away, but now it's smoking pretty badly and keeps puking coolant. (Pretty sure combustion is getting into the anti-freeze, and if I take out the dip stick there is visible smoke coming out as well.)

I'm going to start calling around to see if I can find someone locally to do the repair... if that fails, I'll need to do it myself (which I REALLY don't want to do in the driveway in November in Minnesota!). I've started looking over the repair manuals (TMs), but can anyone give me an idea of how difficult this really is, and approx how much time it should be?

I'm assuming I need the gasket kit:
5714842 - Kit 12456409 - Intake and head gaskets
5714510 - Valve Cover Gaskets
5574856 - Exhaust gaskets
5740031 - 34 Head bolts (summit has multiple kits for a reasonable price)
5743238 - Thermostat

Is there anything else I can expect to need? Do the head bolts need to be replaced or are they re-used on this engine? Edit: head bolts are TTY, so need to be replaced.

Even if I end up paying a shop to do this, I want to try to make sure I have everything they may need down in a list.

 

[springer1981]

I think my girlfriend has the same problem .... not sure sure how much yours will cost but mine cost $50 once a week to fix.

 

[Mogman]

I am sorry this has happened to you it does not sound good.
Yes you need new head bolts, they are stretch to yield and should only be used once.
I would wait until you figure out the actual failure before buying parts, there is a small possibility it could be a failed thermostat unless you have water in the oil, that is game over.

 

[mgFray]

I am sorry this has happened to you it does not sound good.
Yes you need new head bolts, they are stretch to yield and should only be used once.
I would wait until you figure out the actual failure before buying parts, there is a small possibility it could be a failed thermostat unless you have water in the oil, that is game over.

Exhaust is 'sticky' and I pull the dip stick and I can see vapor while it's running. So at this point, I'm convinced it's gone.

(I'll edit the original post with the parts I've got on my list.)

 

[Maxjeep1]

Might be a good time to do headstuds?

 

[mgFray]

Might be a good time to do headstuds?

Since I've got no plans to turbo (or supercharge) the engine, what would be the purpose for headstuds?

I've only put them on high compression/boosted engines in the past.

 

[Maxjeep1]

Since I've got no plans to turbo (or supercharge) the engine, what would be the purpose for headstuds?

I've only put them on high compression/boosted engines in the past.

I would imagine they would have better clamping force and they are reusable. If you ever decided down the road to turbo it. Might be a good selling point for the next buyer that might want a turbo. I don’t like bolts you can’t reuse.

 

[MarkM]

Is the fluid brown in the overflow tank? Does not sound good. I really hate those torque to yield bolts. Good luck.

Mark

 

[Mogman]

Studs are great on the engine stand a PITA in the truck.

 

[Retiredwarhorses]

Start by performing the correct tests to determine if you even have a blown head gasket.
it’s possible you have blowby in the engine and mistook, that does not mean you have blown HG.
ive seen about 99% of the time the over heating was due to the fan not engaging and the operator not paying attention.
you can go from 220-240+ in less than a minute

 

[mgFray]

Is the fluid brown in the overflow tank? Does not sound good. I really hate those torque to yield bolts. Good luck.

No, but I put 2 gallons of fresh coolant in when it overheated. So I don't think it's had time to turn brown. (Maybe only 2 hours of use since then, mostly at idle.)

 

[mgFray]

Start by performing the correct tests to determine if you even have a blown head gasket.
it’s possible you have blowby in the engine and mistook, that does not mean you have blown HG.
ive seen about 99% of the time the over heating was due to the fan not engaging and the operator not paying attention.
you can go from 220-240+ in less than a minute

I did the basics.. fan is working properly. The upper radiator hose gets hot as the engine warms (so the thermostat appears to opening, and there is enough flow.)

The big symptom is the exhaust is white, and the liquid from it is "sticky" when cooled on the tail pipe.

 

[MarkM]

They have a coolant test kit at Autozone that tests for combustion gasses in the coolant.

Mark

 

[mgFray]

Local shop is working with me. Dropped it off today, and they'll look it over the in the next couple days. I gave the shop a USB drive w/ all the HMMWV service manuals on it, and they said they were happy with me buying the parts so we're sure everything is "right" compared to a civilian engine.

In the mean time, the coolant (even with only a few hours on it) IS starting to turn colors a bit. During the 2 mile drive to town, (with noise canceling headphones in) I heard a pop noise then smelled coolant. So I'm pretty sure combustion is getting into the coolant and increasing the pressure enough to pop the 15 psi relief. (This was with the coolant temp below 150F. It never went over 190F during the short drive.

I'm becoming convinced that the cause of my overheating two weekends ago was the head gasket failed and it combustion was raising the PSI in the coolant causing it to slowly go out the relief until it just boiled over completely due to low coolant.

So hopefully it is JUST a head gasket, and not something worse. We'll see.

 

[87cr250r]

So far in my expansive experience of opening 6.2/6.5 engines, both have had erosion of the top deck. I slapped a head gasket on the 6.2 but it always blew bubbles in the coolant and finally got undrivable a few months ago. I bought an eBay 6.5 engine and found similar wear so I had to deck the block. It took 0.011" to clean up.

 

[87cr250r]

To add, of you have a 6.2, maybe you can put a 6.5 head gasket on it to put the fire ring over the undamaged area.

 

[mgFray]

I'v got a 2004 6.5L GEP (detuned) in mine. I'm hoping they don't find any issues with the deck or heads.. but we'll see.

 

[mgFray]

 

[mgFray]

Looks like some glow plug fragments had fallen in to the engine at some point.. some scratches and divets on the top of a few pistons. No scratches on cylinder walls, rings seem good.

head gasket did have signs of a tear/failure in it. So I think I got lucky. The pre combustion cups on the heads have some hairline cracks. Going to have a machine shop check the heads, and suggest to change the cups (or not).

 

[Maxjeep1]

Looks like some glow plug fragments had fallen in to the engine at some point.. some scratches and divets on the top of a few pistons. No scratches on cylinder walls, rings seem good.

head gasket did have signs of a tear/failure in it. So I think I got lucky. The pre combustion cups on the heads have some hairline cracks. Going to have a machine shop check the heads, and suggest to change the cups (or not).

Do you think you could get headstuds on it like it sits? I’m not suggesting that you or anyone else needs them but just for my own curiosity. I seen a guy put a zip tie on the rear studs and slide them into head and set the head and then thread the studs in. I hope I don’t ever have to do what you’re doing. Lol