2001 Jeep GC 4.0 with T6 Rotella T6

[dnewton3]

The positive thing is that the metals are coming down. But I just find this a bit "iffy". The Si is not as low as it should be, because I'd expect the sealers to be washed by now. the Cu is not as low as we'd like to see. If the Pb even hints at rising, then I'd get it back to the shop pronto.

It may be that you just didn't get a good reman ... wouldn't be unheard of.

 

[Donald]

Originally Posted By: dnewton3
The positive thing is that the metals are coming down. But I just find this a bit "iffy". The Si is not as low as it should be, because I'd expect the sealers to be washed by now. the Cu is not as low as we'd like to see. If the Pb even hints at rising, then I'd get it back to the shop pronto.

It may be that you just didn't get a good reman ... wouldn't be unheard of.


I bought the reman engine (Marshall) through RockAuto and paid a shop to install it. At this point with 42K miles and 30 months on the reman there is really not much I can do. It is what it is.

I do not think I will find an oil much better than T6. I can look a 3rd time over the air intake so see if I can find anything.

 

[steve20]

do look over the intake again--not just looking, but take it apart and put it back together triple checking each part. I can't tell you how many times over the last 40+ years, the part LOOKed good, but when you took it off and flexed it the crack appeared---and remember---the crack is always on the side you can't see by looking at it.
Steve

 

[Donald]

Originally Posted By: steve20
do look over the intake again--not just looking, but take it apart and put it back together triple checking each part. I can't tell you how many times over the last 40+ years, the part LOOKed good, but when you took it off and flexed it the crack appeared---and remember---the crack is always on the side you can't see by looking at it.
Steve


Its on my list. Just not on a day when its 7F outside.

 

[SwampSurvivor]

Donald, you and I have the WORST year 4.0. Chrysler really managed to mess up an otherwise very reliable engine for these years.

Head cracking seems to be pretty rare on WJs and TJs - their cooling systems have quite a bit more capacity and don't overheat as bad when they wear out. 0331 head problems seem to be extremely common on XJs because the small cooling system.

Piston skirts ... that's not something that can be avoided. I do see a lot of WJs on CL for < $1000 with knocking engines.

I will be pulling my T6 out around June this year. I should get a UOA. I'm afraid to see what my aluminum will be

I'm fairly certain that I do not have a cracked head. I have a small weep from the WP gasket and I have only had to add 4 or so oz of coolant in 2 years.

I can't see the results of the UOA, so I can't see what the numbers are.

 

[jeepman3071]

Originally Posted By: Miller88
Donald, you and I have the WORST year 4.0. Chrysler really managed to mess up an otherwise very reliable engine for these years.

Head cracking seems to be pretty rare on WJs and TJs - their cooling systems have quite a bit more capacity and don't overheat as bad when they wear out. 0331 head problems seem to be extremely common on XJs because the small cooling system.

Piston skirts ... that's not something that can be avoided. I do see a lot of WJs on CL for < $1000 with knocking engines.

I will be pulling my T6 out around June this year. I should get a UOA. I'm afraid to see what my aluminum will be

I'm fairly certain that I do not have a cracked head. I have a small weep from the WP gasket and I have only had to add 4 or so oz of coolant in 2 years.

I can't see the results of the UOA, so I can't see what the numbers are.


If you only have to add 4 oz of coolant in 2 years I doubt your head is cracked. The 0331 heads do crack, but the internet greatly over emphasizes the issue, and I feel the 0331 head is a more common problem than the piston skirts. Many Jeep 4.0s are on the road without issues.

 

[Donald]

Originally Posted By: jeepman3071
Originally Posted By: Miller88
Donald, you and I have the WORST year 4.0. Chrysler really managed to mess up an otherwise very reliable engine for these years.

Head cracking seems to be pretty rare on WJs and TJs - their cooling systems have quite a bit more capacity and don't overheat as bad when they wear out. 0331 head problems seem to be extremely common on XJs because the small cooling system.

Piston skirts ... that's not something that can be avoided. I do see a lot of WJs on CL for < $1000 with knocking engines.

I will be pulling my T6 out around June this year. I should get a UOA. I'm afraid to see what my aluminum will be

I'm fairly certain that I do not have a cracked head. I have a small weep from the WP gasket and I have only had to add 4 or so oz of coolant in 2 years.

I can't see the results of the UOA, so I can't see what the numbers are.


If you only have to add 4 oz of coolant in 2 years I doubt your head is cracked. The 0331 heads do crack, but the internet greatly over emphasizes the issue, and I feel the 0331 head is a more common problem than the piston skirts. Many Jeep 4.0s are on the road without issues.


With a sensor for low coolant, it would seem to be hard to be unaware of loosing coolant.

Not sure about the cracked #331 head issue but local shop said then had done a few 4.0 engine replacements due to cracked piston skirts, with mine being one of them.

 

[Donald]

Originally Posted By: Miller88

Piston skirts ... that's not something that can be avoided. I do see a lot of WJs on CL for < $1000 with knocking engines.



If someone wanted to flip Jeeps you could buy the Jeeps with a knocking engine for cheap, replace the piston with the cracked skirt and sell it. Hopefully there would be little damage to the cylinder wall.

 

[jeepman3071]

Originally Posted By: Donald


With a sensor for low coolant, it would seem to be hard to be unaware of loosing coolant.


Unfortunately, only Grand Cherokees have a sensor in the reservoir for coolant. A Cherokee or Wrangler could have a reservoir that is bone dry and no warnings would show up. That isn't an excuse though, and I believe the owner of any vehicle that is this old should pop the hood once in awhile to check. I probably open mine at least once a week just to check things, and do the same on my sister's and parent's vehicles.

The good news is the wear numbers are coming down, I would just stick with the Rotella T6 and see how it goes. Unless the engine is knocking or using oil, I wouldn't be too worried.