Finally changed to "high mileage" oil

WestCoastDan

WestCoastDan

TJ Addict
Joined
Sep 2, 2021
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1,115
Location
SoCal
After 5+ years of constantly cleaning the garage floor and then getting a drip tray, and then adding kitty litter to the said drip tray, and buying oil by the quart, and adding oil by the quart and then cleaning the floor again because I forgot to move the drip tray back under the jeep, I finally got tired of managing/dealing with the RMS leak on our '03.

I've tried the RMS leak sealer and it resolved nothing except where to spend $14.
I've also read many posts about changing to 'high mileage' oil as a solution, so I finally figured why not give it a try on the next oil change...
I had always suspected these additives to be more snake oil than motor oil, but I'll admit that I was wrong.

Swapping from conventional 10W-30 to the high mileage, (also conventional) 10W-40 has improved the leak significantly.

I'm not naive enough to think the leak will totally go away, but it has decreased the amount of drips by about 75-80%, which is good enough to avoid replacing the RMS for the foreseeable future.

I would have gone with 15W-40 High mileage if I could have found it locally. Maybe next time.
 
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Good decision, that stopped a big RMS leak I had! However, going with a 15W here in SoCal (and most other parts of the country too) would just cause it to get circulated more slowly at the first start of the day. And to be sure, it's the first start of the day that does the most damage to an internal combustion engine, when the oil is thicker and slower to get to all the nooks and crannies. That's why more some more expensive engines like for aircraft have electric pre-oilers that are run before the engine is started. Personally I won't run anything heavier than a 10W-30 here in SoCal. And if they had a 5W-30 High Mileage conventional I'd run that instead of my current 10W-30.
 
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15w-40 is harder to find in high mileage conventional I think because most 15w-40 is marketed as diesel engine oil with the extra cleaning additives and extra zinc.
I am running 10w-40 but I have just found a high mileage conventional 10w-50 locally, I know its a controversial subject on here but unless you live in the desert in SoCal a 15w oil cold morning start will not harm your worn engine at start up.

Those who have never tried above 10w 30 in a TJ can only speak to 10w-30 because its manufacturer recommended and those that do go to 15w-40 seem to be having no problems what so ever.

How many TJ,s running around out there on 10w-30 with a quart of Moreys or Lucas added :)
 
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Same. Just picked up 6 qt of 10w-30 Napa conventional high mileage. Waiting to do the oil change sometime this week. Coupled w the valve cover gasket, I’m hoping to eliminate my slow drip
 
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Vtx531 said:
Kindof seems like a used car dealer flip it "fix"
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Not at all. Some synthetic engine oils leach the natural oils and preservatives out of seals like the rear main seal which can promote leaks. High mileage oils simply have additional seal restorative additives that restore the seal back to its original consistency. Totally different from something like a radiator stop leak product.
 
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Vtx531 said:
Kindof seems like a used car dealer flip it "fix"
Click to expand...
A rear main seal is enough of a pain that I would totally do the high mileage oil change first and see if it works. However, It totally depends on your engine mileage and how much money you want to spend. If a 20-30 dollar oil change saves you spending over $1k on a higher mileage motor, I don’t see it as a bad move. If you change the oil and it does not stop the leak to an acceptable level, then you can look at the higher cost fix.
 
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It's been my understanding that there are oil deposits that can be preventing a leak by clogging a gap and by adding the detergents in the synthetics, you can actually create leaks as a result. Unless an engine calls for synthetic, I run conventional. This is after I fell down the rabbit hole over at Bobistheoilguy.com for a few weeks a while back.
 
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I run the Valvoline MaxLife high mileage in pretty much every 4.0L I own/service and it does help. It won't stop the leak, but it does slow it down significantly. The RMS on these engines isn't the best design. I replaced mine on the TJ last year and now it still is slightly wet around that area. Much better than before, but I think due to the design it won't ever be completely dry long-term on one of these engines. The valve cover, oil pan, and timing cover are bone dry.
 
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Head Lice said:
Have never heard of that explanation before. Any links?
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Bet you can find them if you clickety-click...

I have read and heard both the crud buildup and conditioner theories, and on some motors it is probably more of a combination of both.

A couple years ago, I had the trans off, as I needed to have the flywheel replaced (my torque wrench malfunctioned and I overtorqued the pressure plate bolts, stripping a few) had the shop just R&R the RMS while they were there. (would have done myself, but there's that thing called time...) But, I do run high mileage 10/30. Motor is so dry, you'd swear it didn't have oil in it... I had a scare when moving from S. FL to N. AL this year with an oil drip/spatter on the rear of Jeep, turned out to be the rear pinion seal. Too bad they don't make high mileage gear oil...
 
Head Lice said:
Have never heard of that explanation before. Any links?
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Nothing I kept. One thing I do know is the records I received with it indicated my BMW never had anything but Castrol 5W-30 synthetic in it and it developed that bad RMS leak I have mentioned before. I was sure thankful to have found the advice in multiple BMW forums to switch to the high mileage conventional which was quick to fix it.
 
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Jerry Bransford said:
Nothing I kept. One thing I do know is the records I received with it indicated my BMW never had anything but Castrol 5W-30 synthetic in it and it developed that bad RMS leak I have mentioned before. I was sure thankful to have found the advice in multiple BMW forums to switch to the high mileage conventional which was quick to fix it.
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What kinda bimmer?
 
TRE3TOP said:
What kinda bimmer?
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An oil leaking one, so it's every BlackMansDream ever made. Was that racist? Sorry, I'll be ok in 2024.

US jugs.jpg
 
Last oil change a few moths ago I used 15W 40 Diesel Dino High Mileage (about two months ago). At first it seemed that it had resolved what appears to be a RMS leak. Just this week i do get an occasional drip after driving. At some point when the clutch needs to replaced I will have the RMS changed at that time. I just keep a drip pan under her when in the driveway so the boss does ride my ass for getting oil stains on the concrete driveway - god forbid!
 
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