1996 Cherokee 4.0L - Mobil 1 HM 10w40 - 4,900 OCI, 150k Miles

[Nick1994]

I finally did a UOA for my Jeep. I had Mobil 1 HM 10w40 in it for 27 months and 4,908 miles. Looks like lead is a bit high? I think I'll change the current fill after a year and report back. What do you guys think of it?

Filter was a Fram Ultra that had been on for 2 OCI's, for a total of 7,765 miles and 37 months.

 

[Brian123]

I would say we cant be hard on your iron numbers since this vehicle gets used off road. Did you save the Fram Ultra Oil Filter?

 

[Nick1994]

I would say we cant be hard on your iron numbers since this vehicle gets used off road. Did you save the Fram Ultra Oil Filter?

I wish I did, I would have cut it open. I didn't think the numbers would be off.

 

[Gasbuggy]

There have been years of posts regarding bad wear numbers with Mobil 1 and 4.0L Jeeps

 

[OilReport99]

For the last 20-30K miles i drove, my old 1995 4.0L used to rattle with everything but [ST] 20W-50. Never did a UOA, but I would guess wear numbers were horrible. Aisin transmission died at 243K. Bought a used one from a junk yard, but at that point I was tired of dealing with the old Jeep. Gave it to my brother and he ran it for another 60K with the used tranny.

 

[KCJeep]

There have been years of posts regarding bad wear numbers with Mobil 1 and 4.0L Jeeps

That is absolutely correct. I am not a Mobil basher at all, I use it too, but it's historically not done well in the Jeep 4.0 in any flavor. It is what it is. I really like the add pack in this oil other than it really should have a higher ZDDP level for a 40 grade HM oil. It used to.

Iron and lead are both high in this sample. Not the end of the world, but I'd use something else. T6 for example.

 

[Gasbuggy]

Yep. Using anything else would probably yield better wear numbers in the 4.0. I think I've seen some great UOAs with Pennzoil, any color bottle.

 

[aquariuscsm]

That is absolutely correct. I am not a Mobil basher at all, I use it too, but it's historically not done well in the Jeep 4.0 in any flavor. It is what it is. I really like the add pack in this oil other than it really should have a higher ZDDP level for a 40 grade HM oil. It used to.

Iron and lead are both high in this sample. Not the end of the world, but I'd use something else. T6 for example.

Yep,Mobil definitely watered down the add pack in this oil quite awhile back. I remember doing a uoa of this exact same oil and the add pack looked weak. I'm guessing back in the M1HM SL days was when it was at its pinnacle.

Maybe give PPHM a go?

 

[Chris142]

Supertech would show better numbers

 

[wpod]

i would imagine 2 years and 5,000 miles are the cause of the higher numbers but I could be wrong.

 

[350Rocket]

i would imagine 2 years and 5,000 miles are the cause of the higher numbers but I could be wrong.

That and possibly dust/dirt depending on the conditions it's used in. That kind of time accumulated is exactly where I would personally do no more than 3k miles or a year.

 

[Chris142]

That and possibly dust/dirt depending on the conditions it's used in. That kind of time accumulated is exactly where I would personally do no more than 3k miles or a year.

Silicon is not bad at all.

 

[350Rocket]

Silicon is not bad at all.

Which leads me to a question I don't know the answer to. What is considered a good silicon number, assuming no other factors contributing (like recent engine work, etc). That number doesn't look terrible but is above the universal average.

I want to do a uoa on my truck soon, especially because it spends most of its time on construction sites with dust blowing everywhere.