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Blown head gasket (3.8l)

17K views 30 replies 9 participants last post by  JonEApelcede  
#1 ·
Hi guys,

My car failed a combustion leak test so I'm thinking of replacing the head gaskets. The leak is combustion into the cooling system (no oil). I was thinking of just using bars leak head gasket sealer and just calling it a day, the car isn't overheating. Before I replaced the lower intake manifold gasket, I tried bars leak intake sealer and it didn't fix that. So I'm a little skeptical on trying the head gasket sealer.

You reckon I should give the head gasket sealer a shot? Or just replace the gaskets/check for warpage. The car runs fine other then the fact that I smell combustion and the cooling system isn't pressurizing properly/bad fuel mileage.
 
#2 ·
I've seen Bar's plug a stream coming out of a head blown to the outside. If anything's going to work, that's it. But being a OHV engine, it's not too bad to do the heads, which is the best way to handle it.
 
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#3 ·
I agree, not a hard job at all. Just find your machine shop before hand so they can pressure test the heads and check them out. While you have the heads at the shop, go ahead and clean the block and the intake surfaces. Don't use the 3M finger pads though, use the proper tools. Make sure to cover the lifter valley and keep track of what goes where. Lots of pictures from all angles is a big help. Oh, and make sure to drain the cooling system before you pull the heads.

You will need a complete gasket set (I used the HS 9996 PT-2) and head bolts. Use factory head bolts as others seem to be hit or miss as these are torque to yield.

If you get all your parts together before hand, you can get this done very easy over a weekend. I bought a set of heads and took them to my machinist so he could get them ready before I did the job. Then all I did was a pull and replace in one shot instead of waiting.

What's your year and mileage?
 
#4 ·
2008 & 136k

I just bought the 2 head gaskets, I don't think I need all the other ones. Will probably get that set tho cause it seems smart. Here's what my lower intake manifold looks like:

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That oil coming out of the intake wasn't there before I did the lower intake manifold gasket a few days ago, I don't know if pressure changed in the engine or what. I'm pretty sure I had head gasket leak before the limg.

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Got the other valve cover off and the exhaust manifolds, tomorrow... off with their heads!
 
#6 ·
Here's the heads, I got them tested for warpage but it would take till Tuesday to get them pressure tested, so I said **** it and started putting them back in. If I have a cracked head then bar's leak to the rescue. This is day 2 of the project, hoping to get everything back together tomorrow, right now it's turning into a PITA getting the push rods lined up with the rockers when seating the heads.

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#7 ·
Great work !

I just took the rocker shafts off and then put them back in after the heads were mounted to the block. Then, while tightening the rocker shaft back into place, I put the pushrods into place. Low torque spec requirement on those rocker bolts and easy enough to do. Worked for me and a whole lot easier IMO.

Please keep us posted on your progress, it looks good.
 
#8 ·
Thanks! I do have one question. When I took out the push rods they unfortunately got mixed up (orientation and position). Does it matter too much? They all look pretty evenly worn, with one side appearing to be more worn on all of them (I would imagine this might be the rocker side?). They are definitely all the same length.
 
#12 ·
I don't envy you on the rear manifold. I was having issues with just the 2 lower bolts on the 3.6, but you have even more. Still waiting on my heads to get back from the machine shop. I'd hoped to be right there with you on progress, but looks like it's next weekend for me.
 
#13 ·
Looks like fun. I agree with removing the rocker shafts. Thinking it may interfere with torquing the head bolts with them installed.

Depending on the cam location there will always be a few valves in the open position. So as you pull down the head bolts in that area, will also be pushing the valve open and the valve spring pressure will be fighting back against your torque wrench. Maybe will not matter ... Just ideal to have the head bolts all torqued equally. Then when tighten the rocker arms they will open the valves as tightened down. ... I would not lose any sleep over it if already done.
 
#14 ·
Looks like fun. I agree with removing the rocker shafts. Thinking it may interfere with torquing the head bolts with them installed.

Depending on the cam location there will always be a few valves in the open position. So as you pull down the head bolts in that area, will also be pushing the valve open and the valve spring pressure will be fighting back against your torque wrench. Maybe will not matter ... Just ideal to have the head bolts all torqued equally. Then when tighten the rocker arms they will open the valves as tightened down. ... I would not lose any sleep over it if already done.
No, it will not interfere with torquing, not at all.
 
#15 ·
Today I got everything back together. On first start up, a little bit of smoke started coming out of the crossover pipe so I turned it off, retorqued and now she's purring like a kitten again. Did the combustion leak test... PASSED!. :D There is a slight squealing noise coming from the engine bay but I'm not sure if that's my belt or inside the engine (might be from the repositioned push rods, it's hard to discern). So far the engine has only idled for around 20 minutes, I am thinking of exhaust leak checking before taking her on the road (as I already fked up on one exhaust component, afraid the manifolds aren't correct). I also noticed I don't have a gasket on my EGR pipe.

So moving forward, is there anything I should look out for? Is it normal for engines to sound a little different upon head gasket replacement? It's been a **** of a 4 days, no one is made to lean over cars for this long! Next time I'm getting an air ratchet. :D
 
#20 ·
Today I got everything back together. On first start up, a little bit of smoke started coming out of the crossover pipe so I turned it off, retorqued and now she's purring like a kitten again. Did the combustion leak test... PASSED!. :DThere is a slight squealing noise coming from the engine bay but I'm not sure if that's my belt or inside the engine (might be from the repositioned push rods, it's hard to discern). So far the engine has only idled for around 20 minutes, I am thinking of exhaust leak checking before taking her on the road (as I already fked up on one exhaust component, afraid the manifolds aren't correct). I also noticed I don't have a gasket on my EGR pipe.

So moving forward, is there anything I should look out for? Is it normal for engines to sound a little different upon head gasket replacement? It's been a **** of a 4 days, no one is made to lean over cars for this long! Next time I'm getting an air ratchet. :D

You'll need that EGR gasket or you will get some nasty fumes in the cabin. Ask me how I know.
 
#17 ·
Great Job!! Check your exhaust bolts (all of them) after one or two cool down cycles. Unless you bought new bolts with new locktite on them, your bolts will back out. I've found the exhaust crossover to be the source of breaking manifold bolts due to it placing "torque" on the manifolds, so what I do is loosen the crossover bolts and see how the manifolds sit in relation to it. If it still lines up okay, torque it back down - then re-torque the manifold bolts. Then I'm done.

Did your exhaust manifolds have gaskets? Some kits, like the one I mentioned, come with exhaust manifold gaskets. However, I've worked on some that have gaskets and some that don't. IIRC from the factory they have no gaskets.
 
#19 · (Edited)
Thanks for all the help guys.

Yes I used all new head bolts and gaskets for the exhaust. Total parts for the job came to around $200-300 as I did all new gaskets down the line (plenum, lower intake, valve covers, exhaust, head). The only bolt that broke during the replacement was one for the plenum cover, pretty crazy considering. Biggest PITA was probably the farthest rear head bolts cause the rear exhaust manifold is in the way. Would recommend anyone attempting to do this to not do it alone and get some sort of impact ratchet (I counted around 70 bolts). Also, get a shop vac for cleaning, couldnt believe how much crap just falls everywhere when removing parts. Glad I saved some money but body isn't too happy with all the labor :ROFLMAO:
 
#22 ·
The ones I used where

FEL-PRO Head Gasket 9997PT - $27.99
FEL-PRO Head Gasket 9981PT - $29.99

Pretty cheap considering. Both were multi-layered, the ones I removed were also. Didn't know they make other ones. Was freaking out a little bit after I torqued the first head down and saw some of the gasket sticking out the side, then saw the rivet :sneaky:.
 
#23 ·
I would think MLS head gaskets are better, as that was a retrofit for my 1996 Plymouth Voyager 2.4L to fix an endemic oil leak at the head gasket. For others, I think you could unbolt a few exhaust hangers to slide the assembly back for better access to the head bolts, as I replaced the catalytic converter in our 2002 T&C 3.8L by sliding the exhaust out the side to attach the new converter. This job is little different than in a classic Mopar engine, since pushrods. I recall that the rockers in my 2002 are stamped steel, appearing almost exactly like those in my 1965 Chrysler 383 engine (but don't interchange). Your 5th gen rockers look like the ones in my 1964 slant six engine, though don't have the adjusters, but neither did the last-gasp slants with hydraulic lifters. The main difference is that the lifters have rollers, as in most/all pushrod engines since ~1990, plus you can't remove the lifters without removing the head, which was also true in the later "peanut head" slant-six engines. I hope you pulled out the lifters and inspected them while you had access. Also, hope you thoroughly cleaned the top of the block and sanded the head (youtubes) against a thick flat glass plate.

I didn't read the back-story. Was the engine overheating or losing coolant, to suspect a head gasket leak? I wouldn't assume one just based on the combustion gas diagnostic, if you used the liquid test (turns from blue to yellow). I have an old Cal Vans kit, but never had luck with it, even when I knew the head gasket was bad (1982 Dodge Aries). I would have run some other tests, like pressurize the coolant system and look for leaks. Anyway, hopefully your engine is better now, or at least not worse.
 
#24 · (Edited)
I failed a combustion leak test and my cooling system has been messed up forever, along with gas mileage. Would have to fill up coolant every week and coolant reeked of combustion.

When I got the heads out I had them checked for warpage and they came out fine, I thoroughly cleaned them along with the block with brake cleaner and a plastic scraper. I would imagine if the heads are level, the block is probably fine. Then again, what do I know, I'm not a mechanic. :ROFLMAO: And I didn't have time to pressure test so I just did the gaskets. Car is running like butter so far, coolant system is finally pressurizing and my gas mileage has significantly improved. Very happy with the results. Only time will tell tho, fingers crossed! :)