2001 Jeep GC 4.0 with T6 Rotella T6

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I am not sure what to say or think. The reman engine is way past breakin. I almost never do short trips, usually 30-40 minutes. I have used the remote starter a few (very cold) times, but then drive it the 30-40 minutes. The T6 seems to have done better than PU for the most part. Not sure whats up with the fuel dilution.



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I'm havine trouble reading the report but from what I can see.Something is coming apart! It's made of metal, I think it's gotten into your bearings from the lead and copper in the report. The 4.0 throws some iron but not tripple didgits, maybe 20-30ppm at the most.

Your airfilter or it's tubing isnt sealed well either but that just a small issue for now. Is this engine still under warranty of any kind?
 
Read the bottom set of numbers, its the most recent with T6 oil. Its past warranty. I have checked the air intake system several times and do not see any problems. The air filter is relatively new, the breather hose and elbow have been replaced along with the PCV, grommet and hose.

The copper is a little high, but not the lead. I would expect both high if a bearing. No oil cooler in this vehicle. So where is the copper coming from? I read some place it can come via a fuel line, but that seems a stretch.

Any chance the Fumoto oil change valve is where the copper is coming from? Its brass.

I was considering replacing the injectors anyway.

I do not consider the TBN low at all.
 
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Thats the best run you've had. I can't read the iron, 36? The aluminum is fantastic though at 1 ppm always a concern in these.

The copper is odd. At this point you've used an oil well known to produce stellar UOA's in the 4.0 so I don't think you're going to do any better oil wise at this point. Your reman just seems to have a rather unique base line I guess.
 
Originally Posted By: Chris142
I'm havine trouble reading the report but from what I can see.Something is coming apart! It's made of metal, I think it's gotten into your bearings from the lead and copper in the report. The 4.0 throws some iron but not tripple didgits, maybe 20-30ppm at the most.

Your airfilter or it's tubing isnt sealed well either but that just a small issue for now. Is this engine still under warranty of any kind?


From what I can see, I think sample #1 is the triple digits for Iron, and it has come down nicely since then. My 4.0 throws around 21 ppm Iron in 5000 miles so it's breaking in nicely, as far as Iron is concerned.

Fuel dilution, on the other hand....what head do you have on the engine? Was it reused in the rebuild and is it an 0331 casting?
 
Originally Posted By: Kuato
Originally Posted By: Chris142
I'm havine trouble reading the report but from what I can see.Something is coming apart! It's made of metal, I think it's gotten into your bearings from the lead and copper in the report. The 4.0 throws some iron but not tripple didgits, maybe 20-30ppm at the most.

Your airfilter or it's tubing isnt sealed well either but that just a small issue for now. Is this engine still under warranty of any kind?


From what I can see, I think sample #1 is the triple digits for Iron, and it has come down nicely since then. My 4.0 throws around 21 ppm Iron in 5000 miles so it's breaking in nicely, as far as Iron is concerned.

Fuel dilution, on the other hand....what head do you have on the engine? Was it reused in the rebuild and is it an 0331 casting?



The engine was a complete reman from Marshall Engines just needing tin. The head is whatever they used.
 
The rotella run looks fine other than your cold starts are brutal. You might throw in an italian tuneup every few thousand miles to really burn that gas out of the oil or stop with the cold start idling.
 
Originally Posted By: badtlc
The rotella run looks fine other than your cold starts are brutal. You might throw in an italian tuneup every few thousand miles to really burn that gas out of the oil or stop with the cold start idling.


So lets say I remote start my Jeep and let it run 5 minutes, then drive at 40 to 60 MPH for 30 minutes. Won't it have "burned" off any fuel that was in the oil?
 
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Should have, unless your thermostat is keeping things too cool.

But an italian tune up's purpose is to get things hot, not warm, so higher load, acceleration runs, up a mountain etc are what you want.

Or drop a gear/hold a lower gear a bit more when you can and let it purr a bit more.
 
Looking back for other Jeep 4.0 engines I found one UOA with 2 @ 3500 and another one with 6 @ 3500 miles. So mine is 16 at 5000 so significantly higher.
 
Originally Posted By: Kuato

From what I can see, I think sample #1 is the triple digits for Iron, and it has come down nicely since then. My 4.0 throws around 21 ppm Iron in 5000 miles so it's breaking in nicely, as far as Iron is concerned.

Fuel dilution, on the other hand....what head do you have on the engine? Was it reused in the rebuild and is it an 0331 casting?




This is a good point. A lot of the rebuilds I have seen have used rebuilt 0331 heads, and some of them crack. When removing an 0331 head, I only replace it with a NEW beefed up version. I would pop the valve cover and see what casting it has. If its a newer improved casting (02-06) it will have "TUPY" in addition to 0331. It might be worth it to contact Marshall and see what they use. I have heard of people contacting Jasper engines, and they denied the 0331 head as an issue, which we all know it is.

If the head was cracked you would probably be losing a noticeable amount of coolant, which I don't think you mentioned. I don't think this is an issue at this point.

The fuel injector idea could be a possibility, although fairly rare. How easily does the Jeep start after sitting over night? If it has longer crank times, your injectors could be leaking down when it sits.

Making sure the engine temp is correct is also important. I would get one of those IR temp guns and test the temp at different parts of the engine/cooling system. The factory sensors aren't the most reliable in the world.

With all that said, there is definitely improvement. Was this the first run with T6? I would do another similar run and see how it compares. I might do a 5,000 run on Rotella T6 in a friend's 2000 Cherokee 4.0 just to see how it compares.

Maybe they used some sort of sealant containing copper on some of the gaskets when reassembling the engine?
 
I am aware of the 0331 head issue. But how much bad luck will one Jeep Grand Cherokee have? It had the cracked piston skirts, Teves calipers and has twice needed a pressure sensor and pressure governor in the transmission (all OEM parts both times).

I have T6 in it now. Will again go to 5000 miles.

The Jeep starts and runs fine. Its awesome in the snow while my pickup sits waiting for the snow to melt.

Going to get new injectors from Trav?
 
Donald,

I would not be nervous about the fuel. 2.2% is not outlandish at all where GC measurements are used. GC is a much more precise method for measuring fuel than the methods employed by most other labs.

If I understand correctly the first 2 samples were with PU? Notice the first 2 samples the fuel % is an estimate. That is because Polaris only does the GC when there is X% viscosity loss. The first 2 samples did not meet this min requirement so GC was not performed. The Rotella sheared enough to meet their protocol for GC, but is still in grade.

The numbers are trending down and I would not be overly concerned at this point.
 
Originally Posted By: REDDOG
Donald,

I would not be nervous about the fuel. 2.2% is not outlandish at all where GC measurements are used. GC is a much more precise method for measuring fuel than the methods employed by most other labs.

If I understand correctly the first 2 samples were with PU? Notice the first 2 samples the fuel % is an estimate. That is because Polaris only does the GC when there is X% viscosity loss. The first 2 samples did not meet this min requirement so GC was not performed. The Rotella sheared enough to meet their protocol for GC, but is still in grade.

The numbers are trending down and I would not be overly concerned at this point.


Interesting, I had seen the "estimate" comment but did not know why is was an estimate vs actual test.

Yes, first two were PU and and last was T6. I assume your suggesting to keep with T6 since overall its coming out the best?
 
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