Head Gasket Blown Again

PJOJeep

PJOJeep

2000 TJ Since New
Supporting Member
Joined
Jan 31, 2019
Messages
209
Location
Northern Illinois
Appears I have another blown head gasket! Several years ago I replaced it with a new Felpro gasket. 4.0L with 216,000 miles, loosing a little power on hills. I realize it’s done that since new...but I notice it more now like the last time. I did a quick cold compression check a few weeks ago, 1,2,5,&6 at 150, 3&4 around 120.
Any one else have issues with blowing out gasket between cylinders?
Plan to do hot compression check, maybe a wet check, then I just got a set of gauges for a leak down test.
 
Rubicon John said:
Do the leak down to verify it’s actually the gasket. Could be leaking past the rings.
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Thank, that’s why I bought the gauges to that, just seems too much of a coincident that the same 2 cylinders low. I was real obvious last time! I might try a Victor gasket this time If it is.
 
I wouldn't be sure it's the gasket either. Could be a cracked 0331 head amongst other possibilities. Also, a warped head or deck will repeatedly blow gaskets out.
 
Skylinessuck said:
I wouldn't be sure it's the gasket either. Could be a cracked 0331 head amongst other possibilities. Also, a warped head or deck will repeatedly blow gaskets out.
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You’re a buzz kill skylines! Ha! Ouch, I hope it’s a gasket. But I would think it’s a little odd that two piston rings would fail simultaneously unless there was a specific cause.
Good to do the test, but gasket or other worse would seem more likely, since it’s causing effect in 2 locations.

I keep reading about 3 injector getting hotter fuel and vapor and causing issues like this. Read about that last night I think?
 
Sorry for possible bad news 😞 I doubt it's the injector as that's usually just after it sits idling when it's hot out and goes away. But if it was a blown gasket, I would expect to see lower compression numbers than that. Maybe not? Did you have the head checked for flatness when you did the gasket last time? Have you looked for other blown gasket signs like oil in the coolant or vise versa?
 
Skylinessuck said:
I wouldn't be sure it's the gasket either. Could be a cracked 0331 head amongst other possibilities. Also, a warped head or deck will repeatedly blow gaskets out.
Click to expand...
I had the head checked and surfaced last time, and there is no issue with antifreeze in the oil or vice versa. I plan to get a straight edge this time and check the block and head before putting it back together.
 
So you've decided to take it apart then? I'd do a leak down test and check for slack in the push rods first. Does it make any noises?
 
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