Oil Suggestions for a 2003 Jeep Grand Cherokee 4.0 with 93,250 miles that has a small rear main leak. Current fill is Castrol EDGE 10w-30 with a FRAM
2003 Jeep Grand Cherokee rear main drip
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Replace the RMS. It won't stop leaking.
Nothing will completely fix the leak. I would opt for a 10w30 HM oil however.
I had great luck with M1 HM 10w30 and mine had about 145,000 miles on it. I later had the RMS replaced only because I was concerned about having a cracked piston skirt and wanted to check out the insides.
Knowing what I know now, I would have continued with the M1 HM and then switched to either QS Defy or Pennzoil HM. It would have saved me $350 too.
Knowing what I know now, I would have continued with the M1 HM and then switched to either QS Defy or Pennzoil HM. It would have saved me $350 too.
Try a high mileage oil. My firebird had what I believe was a rear main leak and Pennzoil high mileage stopped it almost entirely. In the past 2 months I've only seen one or two drips total. It used to be a couple of drips every day.
If keeping the vehicle, I would fix it. Ed
check the oul pan bolts nearest the 2 cats.mine and a customers bolts backed off in that area and it looked like a rear main.just loose pan bolts.
Nick1994
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I changed the rear main seal in my grandpa's 96' Cherokee with the 4.0L last winter. It still drips just as much, and that's with 10w40 MaxLife
Pennzoil HM if you like quiet, Maxlife if you don't care. A good chance it will slow it down anyway.
I have heard that adding Liqui Moly Oil Saver is a good additive.
However, nobody should expect an oil or additive to cure a leaking seal.
However, nobody should expect an oil or additive to cure a leaking seal.
I've had good luck with Maxlife in slowing leaking seals, sometimes down to nil.
I'd try this as a first resort.
Replacing the rear main seal would not be a fun job.
I'm guessing that you'd have two driveshafts and the transfer case to remove before even touching the heavy automatic.Once everything is out, replacement should be easy.
It's getting to it and then putting everything back together that would be hard.
OTOH, this is a 93K vehicle, so it might be worth fixing it properly if it's pretty decent overall.
I'd try this as a first resort.
Replacing the rear main seal would not be a fun job.
I'm guessing that you'd have two driveshafts and the transfer case to remove before even touching the heavy automatic.Once everything is out, replacement should be easy.
It's getting to it and then putting everything back together that would be hard.
OTOH, this is a 93K vehicle, so it might be worth fixing it properly if it's pretty decent overall.
Thanks for the Replies. I recently changed the rear main seal in my Moms 01 Jeep Cherokees 4.0 with Good results, used a Crown brand seal as replacement for the 123,??? mile Timkin that was leaking.
This 2003 Jeep Grand Cherokees 4.0 im taking care of has a very small rear main leak compared to most leaking 4.Oz that i have seen, and i wanted to hear what High Mileage oils other people have used with good results. Im Not afraid of jacking this Jeep up, letting front axle droop so oil pan Slides out with only #7 main bearing cap to remove for acces to rear main seal. Some day Motul 300V Chrono 10w-40 or Power 5w40 will hopefully be bought for this Jeep, at which time rear main will be replaced. Want to get to 100,000 miles first before cracking into this 4pointOH.
+1 ... I used 1.5 cans (bought from NAPA) and two jeep 4.0 moderate seal leaks stabilized - good product ! Made in Germany ...Can't go wrong .
Originally Posted By: artificialist
I have heard that adding Liqui Moly Oil Saver is a good additive.
However, nobody should expect an oil or additive to cure a leaking seal.
Originally Posted By: artificialist
I have heard that adding Liqui Moly Oil Saver is a good additive.
However, nobody should expect an oil or additive to cure a leaking seal.
Many times what is described as a rear main seal leak on a 4.0 is not the rear main seal at all. The valve cover gasket, oil pressure sending unit and oil pan gaskets will all leak and run down to the same spot. I'd try a valve cover gasket first.
Originally Posted By: Nick1994
I changed the rear main seal in my grandpa's 96' Cherokee with the 4.0L last winter. It still drips just as much, and that's with 10w40 MaxLife
I bet its not the rear main seal. Check the oil filter adapter O-ring. They harden over time and leak, mine leaked A LOT. $3 in parts and it stopped. They also leak from the valve cover and oil pan. My bet is it is one of those and the oil is running down towards the back of the engine since it is tilted back in the vehicle.
I changed the rear main seal in my grandpa's 96' Cherokee with the 4.0L last winter. It still drips just as much, and that's with 10w40 MaxLife
I bet its not the rear main seal. Check the oil filter adapter O-ring. They harden over time and leak, mine leaked A LOT. $3 in parts and it stopped. They also leak from the valve cover and oil pan. My bet is it is one of those and the oil is running down towards the back of the engine since it is tilted back in the vehicle.
The oil filter adaptor leaks from the oil filter adaptor area, thats on the pass side of a Jeep 4.0, of course Jeep WJ 4.0s dont have oil filter adaptors, the oil filters spin right onto the block like a Toyo 20R or 22R. If it was a valve cover leak, the cylinder head and top of block would be oily, on 1996-2006 Jeep 4.0s usually the back of 1 piece valve cover, and 1987-1995 any where from front to back of RTV valve cover gasket. This isnt my 1st 4.0, just wondering which oils people have had good luck slowing down Jeep 4.0 rear main leaks, Thanks!
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