Need advice on oil

[JeepWJ19]

Hi all

I really need some advice on my 4.0 of what oil to use. Some background knowledge - got it 4 years ago with 80k miles. It currently has 125k miles on it now. It has just started ticking really bad on cold start, and then on operating temperature it quiets. My mechanic already looked for exhaust leaks / broken bolts and couldn't find any. He used seafoam to check for the leak so he told me to run it for a week and then report back to him. I go to pick it up today and find out the full detail.

I believe it is my lifters are collapsed and will need to get new lifters and new camshaft. The reason is the cold start tick. I start the Jeep, it is fine the first few seconds and then it starts ticking, the engine shakes, and the exhaust burbles. Someone told me that is 99% collapsed lifter and not pushing up oil through the valves? But I want a better oil. I've been using Pennzoil High Mileage since 80k (do not know what original owners used). No signs of leaking (I check my oil every week). I believe I do not need HM oil as the head and block are spotless and I see no signs of a rear main seal leak (although that could be because of the HM?). I've spent the past two weeks everyday trying to decide which is the best oil for my 4.0. From what I've been reading I need an oil with a lot of ZDDP because the flat tappet engines love those? I've been thinking of switching to Rotella t6 10w30 or 5w30 (i cannot remember what my service manual says to use), but my friend tells me to get Mobil1 Syn. They both seem pretty equivalent but I would like your opinion since you guys are the experts.

Thanks all!

 

[xshoex]

In my 4.0 i use 15w40 in summer and 5w40 in winter theres tons of people who love a 40wt in the 4.0

 

[JeepWJ19]

Originally Posted By: rickmeseke
In my 4.0 i use 15w40 in summer and 5w40 in winter theres tons of people who love a 40wt in the 4.0


Hey thanks, but Im not really looking for a 15w40. I think 15w on my WJ is too thick on cold start. I think the cold start tick is due to using a heavier oil. I've read that 40wt really quiets the lifters but that is only a mask, correct? I think I'd rather stick to the service manual.

Thank you!

 

[edvanp]

I had a high mileage '99 Jeep Cherokee Classic that my daughter drove in high school with the 4.0 engine. I tried a lot of different oils in it but for the money, Quaker State Defy 10w30 worked very well!

 

[Rand]

Originally Posted By: JeepWJ19
Originally Posted By: rickmeseke
In my 4.0 i use 15w40 in summer and 5w40 in winter theres tons of people who love a 40wt in the 4.0


Hey thanks, but Im not really looking for a 15w40. I think 15w on my WJ is too thick on cold start. I think the cold start tick is due to using a heavier oil. I've read that 40wt really quiets the lifters but that is only a mask, correct? I think I'd rather stick to the service manual.
Thank you!

15w40 is not too thick for startup in the summertime its many times thinner than 10w30 is in the wintertime.

10w30 may not be adequate if you get any of those -10F days we got last year here in Ohio.

Rotella T6 5w40 would be a good option.

 

[threeputtpar]

Have you been using the same brand of filter for all of the oil changes? Possibly you have a filter with a bad anti drain back valve.

There's a member on this board, KCjeep, that has tries most of the filters and oil in his 4.0. Hopefully he'll see this and weigh in for you.

 

[SilverC6]

T5 semi-synthetic Rotella in the 10w30 variety might just be the right ticket.

My old 4.0L liked the combination of Pennzoil Platinum 5w30 and Wix filters.

 

[440Magnum]

I've been running T6 5w40 for years now, and love it. The '99 has about 170k miles and can still go a 7000 mile OCI without adding a quart. Pressure is right in the good zone, doesn't fall too low at hot idle. The engine is rather quiet for a 4.0, but I've never considered noise to be representative of protection.

4.0s seem to thrive on 40s even though they were always spec'd for 30s- but I wouldn't throw a conventional 15w40 HDEO in there- too slow to get moving on startup, even in hot weather. If you're going 40, go with T6, M1 TDT, or another good synthetic. I prefer 40s and HDEOs in that engine because of the flat tappet cam, but in all honesty if its well broken-in, any xw30 will protect the cam just fine.

 

[440Magnum]

Originally Posted By: JeepWJ19
I've read that 40wt really quiets the lifters but that is only a mask, correct? I think I'd rather stick to the service manual.

Thank you!

Noise doesn't equate to wear, that is correct. But there are some good engineering reasons for going a little thicker on a 4.0. They don't run a lot of oil pressure even when new, and as they age the oil pump clearances and cam bearing clearances open up and a fair number of them will fall out of spec at hot idle if the tolerances "stack" the wrong way- my 2001 did that at only about 100k miles, and I ultimately went ahead and swapped in a new oil pump. A high viscosity index oil in the light 40 to heavy 30 range (eg. T6 5w40) will help with that.

 

[JeepWJ19]

Wow all! Thanks for the help.

Would it be safer to try Rotella T5 first then switch it over to T6? I think the 5w40 sounds like a nice choice in the winter and 10w40 in the summer?

I am still a little worried about the seals leaking. I am fine with a little leak because I can prepare for that but what I don't want is a major dump sitting at a red light.

To answer the question : I have been using the factory Mopar MO-090 for since I got the Jeep. I even changed the filter last time to make sure it just wasn't a bad filter. I don't know what brands of Wix or Purolator my jeep calls for.

As far as I can tell there is no leaking what so ever, but that could obviously change once new oils are used and the seals go back to their original size. I don't think that would cause all the oil to do a complete dump. I would be under major suspicion if I was still leaking oil with an HM. Either way I want to get off the HM, just done with it.

Again, thanks guys very much! Greatly appreciate it!

 

[JeepWJ19]

I suspect that I just have a dirty engine?

The people before me lived locally to where Im at, they were elderly. They lived right across from a food store and a mile away from a gas station and a pharmacy so I'm guessing they didn't have far to go. But I too also made a lot of short trips, a some long ones too but Im assuming it has just accumulated every time. I usually drive about 10-20 miles to college everyday, using the entrance ramp as an excuse to give it wide open throttle to try to knock loose any sludge buildup but maybe it didn't do the trick.

Would it be dirty? I usually go 3500 OCI and that's the limit. Every time oil is just pitch black but I thought 3500 miles is pretty short for it to be pitch black? Maybe that's just how it is? What do you guys think?

I always babied it for the longest time, never really saw above 2500RPM because I've read about how unreliable the transmission can be but I read a service bulletin by Chrysler that my Jeep's 4.0 is known to have carbon build-up when RPMs don't reach at least 3200RPM. So now I've recently been giving her a little more gas while also in fair conditions.

 

[440Magnum]

Originally Posted By: JeepWJ19
Wow all! Thanks for the help.

Would it be safer to try Rotella T5 first then switch it over to T6? I think the 5w40 sounds like a nice choice in the winter and 10w40 in the summer?

I am still a little worried about the seals leaking. I am fine with a little leak because I can prepare for that but what I don't want is a major dump sitting at a red light.

To answer the question : I have been using the factory Mopar MO-090 for since I got the Jeep. I even changed the filter last time to make sure it just wasn't a bad filter. I don't know what brands of Wix or Purolator my jeep calls for.



Its not a question of T5 being "safer" than T6. But it is cheaper. I'd pick one grade and go year-round, 10w40 and 5w40 are exactly the same when hot anyway, they only become different at extreme cold. 5w40 year-round if you're going to spend the slight extra for T6.

As far as a filter goes, the 4.0 spec's a very standard filter. The actual spec is for a Fram xx16 (XG16 for the Ultra, TG16 for Toughgard). But it will accept the longer xx8A size (XG8A for Ultra) with more filter area. The Purolator equivalent is xL14670 (shorty) or xL30001 for the long one. The Wix equivalent "short" size 51085, is "long" size is 51515.

I use either Fram XG8A (Fram Ultra, long size), PSL30001 (Purolator synthetic, long size) or Royal Purple 30-8A (long) on my Jeep.

 

[Clevy]

Y

Originally Posted By: JeepWJ19
Wow all! Thanks for the help.

Would it be safer to try Rotella T5 first then switch it over to T6? I think the 5w40 sounds like a nice choice in the winter and 10w40 in the summer?

I am still a little worried about the seals leaking. I am fine with a little leak because I can prepare for that but what I don't want is a major dump sitting at a red light.

To answer the question : I have been using the factory Mopar MO-090 for since I got the Jeep. I even changed the filter last time to make sure it just wasn't a bad filter. I don't know what brands of Wix or Purolator my jeep calls for.

As far as I can tell there is no leaking what so ever, but that could obviously change once new oils are used and the seals go back to their original size. I don't think that would cause all the oil to do a complete dump. I would be under major suspicion if I was still leaking oil with an HM. Either way I want to get off the HM, just done with it.

Again, thanks guys very much! Greatly appreciate it!


Talk to kcjeep. He's an expert as far as I'm concerned.

And 3500 mile interval on synthetic is an utter waste of money and resources. Any conventional will easily run that interval.
If the engine is sludged use a product in the crankcase like seafoam or mmo. Go a grade thicker to compensate for the solvent thinning the oil. Run it the full interval.
The 4.0 is a tractor motor. It needs nothing special. If using a synthetic 10000 miles is easily achievable. 3500 mile intervals is dumb and a waste.
An end of interval flush product will also help with sludge. I use them on new to me vehicles when I can see deposits. I've never had a problem with their use nor lost an engine. Follow the instruction. It's that simple.
If the engine is sludged up but it's not causing any running problems I'd just leave it alone. If you are goi g to stick with short intervals use a conventional.

 

[JeepWJ19]

Thats what the mechanic said. He said he would drop the HM and go to just a dino oil. So does Rotella make a dyno oil that is really good?

Im not due for another oil change until 2500 miles. That'll be getting towards the fall so I should switch it to 5w40?

Thanks

 

[JeepWJ19]

It seems that since I have a 4.0 and they like pretty much anything I should just stick with a regular dino?

What would be the best. I just did some searching on BITOG and a lot of people say PYB is a definite good one. But when I went to their website their HM is rated as a better cleaner and lubricant vs the standard YB. Is PYB still worth getting, I've used Pennzoil and so has my father all of mine and his life and it seems to be a good oil and would prefer to stick with it unless it is really bad. Although further research suggests that almost all name brand conventional oils are about the same. So I would ask the question : is it even worth it to switch from Pennzoil HM to PYB?

Thanks all! You all are a big help

 

[440Magnum]

I'll say again: T6 5w40 year-round, 6000 mile (or more) oil change interval, synthetic filter (eg. Fram Ultra.) in a PH8A size if it'll fit (needs about 2" more length than the OEM filter, same diameter, same gasket, same bypass pressure, etc., just more media). Can't go wrong that way.

 

[JeepWJ19]

Sounds good. Ive heard nothing bad about Rotella.

What are the odds I'll need my seals replaced haha?

I'll run the jeep with the seafoam in the crankcase for 200 miles then I'll drain the oil

 

[440Magnum]

Originally Posted By: JeepWJ19
Sounds good. Ive heard nothing bad about Rotella.

What are the odds I'll need my seals replaced haha?

I'll run the jeep with the seafoam in the crankcase for 200 miles then I'll drain the oil

Its a Jeep 4-leaker... it WILL develop very slow (usually) leaks at a few places over the course of years:

The rear main seal tends to leak, but it will just put a palm-sized dab of oil down overnight at the worst. More like a dime-sized or quarter-sized drop in most cases.

The valve cover gasket will begin to weep with age. Most engines of all types do that, so the 4.0 isn't special in that regard.

Both of the above leaks will cost you less than a quart per change interval unless they get really, really bad, which is rare.

The biggest risk of a leak that will need immediate attention is the O-ring under the right-angle adapter for the oil filter. When it goes, it will drip steadily while the engine is running, because that passage is under ~40psi of pressure. Its a pretty easy fix, you just have to find a short, large-size Torx that can fit between the right-angle adapter and the frame rail to remove the right-angle adapter, replace the O-ring, and re-install. Any competent Jeep shop can do it in an hour.

IME, Synthetic oil won't trigger any of those leaks. Time and wear cause them. Mostly time. If anything is going to put you at risk of leaks, it would be using gimmick juice like Seafoam in the crankcase. I recommend just good oil, no additives.

 

[dlundblad]

I recognize you from Jeep Forum. I saw the latest Jeep 4.0 lifter tick thread, but decided to stay out of it this time as all the false information would just frustrate me.

Pennzoil High Mileage 10w30 or if you want to get tricky, (1) 5 quart jug of Pennzoil conventional 10w40 and 1 quart of 5w20. Both oils have higher TBN's just like the mentioned HDEO's. The only difference is that the Pennzoil will have high amounts of molybdenum, which the 4.0s tend to love in regards to anti-wear additives.

As far as filters, I've had great luck with Fram Tough Guards and Mopar/ Motorcrafts.

Id be using one of the above right now, but I had a leaking emergency in the garage.

 

[JeepWJ19]

Pennzoil High Mileage is what Im using now and have always used... 10w30

I recognize your name as well , you've been a lot of help

I have been reading extensively on BITOG and the general consensus say there is no real benefit to HM oils unless you have an oil leak. I see no sign of me having an oil leak or burning any oil. But how can I be sure since all I have been using is an HM oil?

What's the point of using an HM oil if I don't have a leak or burning any oil?