Which oil to use for my Jeep 4.0?

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I lead about a half dozen snow runs every year. I break trail all day spinning 600+ lbs of tires and still run 5W30 Quaker State HP or UD.
 
Originally Posted By: Zaedock
I lead about a half dozen snow runs every year. I break trail all day spinning 600+ lbs of tires and still run 5W30 Quaker State HP or UD.

Not sure if you took offense, as there is no emotion attached to text !
If so I was joking. Well I was serious but joking about the delivery !
 
Originally Posted By: dlundblad
Originally Posted By: Donald

All synthetic oil contains seal conditioners, the HM stuff normally has seal swellers (not for me).



I guess I didn't know there was a difference between a seal conditioner and seal sweller.


I think in brand name oils where these additives are blended in the oil the producer is using proven additives in the correct amount to provide some benefit with low risk of causing damage to the seals.

What scares me is the aftermarket stop leak products, they swell every seal in the engine not just one individual seal.
How do you know how much is beneficial and at what point is the additive doing harm, its a roll of the dice i just as soon avoid.

The other problem today is the seal materials are so much better than years ago meaning they are more resistant to these kinds of products.
Unless you built the engine and know what every seal is made of the one you are hoping to seal may be totally resistant but others that are not having issues may be effected.

I may be wrong but it is my understanding the conditioners used in engine oils are ester based.
Only the percentage is different in HM oils. These can soften or "condition" some types of seal materials but have no effect on others.
 
Originally Posted By: Zaedock
Realistically, PYB in the 5W30 flavor is all his 4.0L needs in winter. IMO, there is no need to run any XW40 unless you're snow wheeling and experience increased oil temps.

The 4.0L is a simple engine. No need to overthink the lube.


Lots of people use Xw-40 because "40 weight oil is heavy duty" or because "that engine is a dinosaur"

I would bet the Rambler engineers that designed that engine series in 1964 never in the remotest rearmost part of the back of their head imagined a SAE 40 oil should be used in them. 1964 was the era of SAE 20 and 10w-30. Straight 30 was only recommended for ambient temperatures in excess of 90 °F. If you really wanted to get fancy they had 5w-20. 20w-50 existed on the other side of the pond, for the Austin Mini's shared engine/gearbox sump.

We have a '99 4.0, we used GTX 10w-30 when we first brought it down in 2009, MS5K 10w-30 or 5w-30 since then, and QSUD 10w-30 since last week.
 
Originally Posted By: wsar10
Originally Posted By: Zaedock
I lead about a half dozen snow runs every year. I break trail all day spinning 600+ lbs of tires and still run 5W30 Quaker State HP or UD.

Not sure if you took offense, as there is no emotion attached to text !
If so I was joking. Well I was serious but joking about the delivery !


Nope, no offense at all! I was only pointing out to everyone that I beat the snot out of my rig in winter and summer with modern grpIII 5W30.
 
Originally Posted By: Zaedock
Your 4.0L does not require a daily dose of ZDDP. SM/SN rated oil has plenty for the factory low tension valve springs. I like the 5W30 SOPUS GrpIII synthetics, but if the TDT has been working well for 50K, why change?

I have always felt that 2.5/4.0/258 engines have only adequate valve train oiling and have repaired about a half dozen noisy lifter Jeeps with a HV Melling oil pump. In my experience, the factory oil pump life expectancy is about your mileage anyway, so you may want to look into it.



With your experience? That's a new one on me. Even after a quick google search a failing oil pump isn't that common. I even gave it the benefit of the doubt by rewording my search.. still nothing much. Not saying they never fail, but they normally last the life of the engine.
 
After reading through the posts, I think ive decided to just try some stuff out.

Ill finish my M1 10w30 HM then get a UOA.. I do want to either try 5w30 HM or 0w 40 this winter. Then get another UOA. Then maybe come spring/ summer ill give the TDT and RT6 a try with more UOA's.

As much as the noise drives me nuts, its still possible to have better wear numbers with MORE noise. Ill just go from here and see how my Jeep likes the different flavors.
 
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I recently asked the same question, and decided to go with the Ow40 in both of my Jeeps (2.5L and 4.0L). It was a toss up between that and the 0w30. For a purely winter choice, I'd lean toward the 0w30. The 10w30 seems to have the worst specs of the M1's, the 5w30 actually seems to be better.
I understand what you mean about thinner oils and a quieter valve train. I can't help but think that it's related to the jeeps lifter design.
 
Originally Posted By: Cardenio327
Originally Posted By: Zaedock
Realistically, PYB in the 5W30 flavor is all his 4.0L needs in winter. IMO, there is no need to run any XW40 unless you're snow wheeling and experience increased oil temps.

The 4.0L is a simple engine. No need to overthink the lube.


Lots of people use Xw-40 because "40 weight oil is heavy duty" or because "that engine is a dinosaur"

I would bet the Rambler engineers that designed that engine series in 1964 never in the remotest rearmost part of the back of their head imagined a SAE 40 oil should be used in them. 1964 was the era of SAE 20 and 10w-30. Straight 30 was only recommended for ambient temperatures in excess of 90 °F. If you really wanted to get fancy they had 5w-20. 20w-50 existed on the other side of the pond, for the Austin Mini's shared engine/gearbox sump.

We have a '99 4.0, we used GTX 10w-30 when we first brought it down in 2009, MS5K 10w-30 or 5w-30 since then, and QSUD 10w-30 since last week.


I'm a light oil person where it's warranted, however, in the case of the AMC 4.0 - the UOAs show that they wear less on a 40 grade oil.

Will it make any difference in the life? Probably not.
 
Originally Posted By: dlundblad
Originally Posted By: Zaedock
Your 4.0L does not require a daily dose of ZDDP. SM/SN rated oil has plenty for the factory low tension valve springs. I like the 5W30 SOPUS GrpIII synthetics, but if the TDT has been working well for 50K, why change?

I have always felt that 2.5/4.0/258 engines have only adequate valve train oiling and have repaired about a half dozen noisy lifter Jeeps with a HV Melling oil pump. In my experience, the factory oil pump life expectancy is about your mileage anyway, so you may want to look into it.



With your experience? That's a new one on me. Even after a quick google search a failing oil pump isn't that common. I even gave it the benefit of the doubt by rewording my search.. still nothing much. Not saying they never fail, but they normally last the life of the engine.


I have quite a bit of experience rebuilding Jeep 2.5/4.0/258 engines. I think I may have a 199 or 232 under my belt too. I also have a lot of experience driving these engines in very precarious off road situations. By life expectancy, I don't mean absolute failure. The oil pump can "last" for 300K miles, but it loses efficiency. Google Jeep tick and you'll find countless threads on the dreaded issue. I have repaired several of the tick issues during rear main replacement by installing a Melling HV pump at the same time. In one severe case (I mean it was a LOUD lifter tick!) it was night and day. My friend thought I swapped engines!
Google 4.0L and allpar for more info on the 4.0L.

Originally Posted By: Miller88
I'm a light oil person where it's warranted, however, in the case of the AMC 4.0 - the UOAs show that they wear less on a 40 grade oil.

Will it make any difference in the life? Probably not.


The best 4.0L UOA I've seen on here was on Havoline 10W30. The Fe numbers were insanely low. I also achieved single digit numbers during a wheeling season on the $.99/gal Delo SAE30 I scored years ago. So far, The 2.5L in my trail rig likes the QS UD 5W30. The Fe numbers were very low and the drivability is so much better with the lower viscosity compared to the SAE30 or a XW40, especially with the start/stopping on the tougher trails.
 
Originally Posted By: Zaedock

Originally Posted By: dlundblad
Originally Posted By: Zaedock
Your 4.0L does not require a daily dose of ZDDP. SM/SN rated oil has plenty for the factory low tension valve springs. I like the 5W30 SOPUS GrpIII synthetics, but if the TDT has been working well for 50K, why change?

I have always felt that 2.5/4.0/258 engines have only adequate valve train oiling and have repaired about a half dozen noisy lifter Jeeps with a HV Melling oil pump. In my experience, the factory oil pump life expectancy is about your mileage anyway, so you may want to look into it.



With your experience? That's a new one on me. Even after a quick google search a failing oil pump isn't that common. I even gave it the benefit of the doubt by rewording my search.. still nothing much. Not saying they never fail, but they normally last the life of the engine.


I have quite a bit of experience rebuilding Jeep 2.5/4.0/258 engines. I think I may have a 199 or 232 under my belt too. I also have a lot of experience driving these engines in very precarious off road situations. By life expectancy, I don't mean absolute failure. The oil pump can "last" for 300K miles, but it loses efficiency. Google Jeep tick and you'll find countless threads on the dreaded issue. I have repaired several of the tick issues during rear main replacement by installing a Melling HV pump at the same time. In one severe case (I mean it was a LOUD lifter tick!) it was night and day. My friend thought I swapped engines!
Google 4.0L and allpar for more info on the 4.0L.

Originally Posted By: Miller88
I'm a light oil person where it's warranted, however, in the case of the AMC 4.0 - the UOAs show that they wear less on a 40 grade oil.

Will it make any difference in the life? Probably not.


The best 4.0L UOA I've seen on here was on Havoline 10W30. The Fe numbers were insanely low. I also achieved single digit numbers during a wheeling season on the $.99/gal Delo SAE30 I scored years ago. So far, The 2.5L in my trail rig likes the QS UD 5W30. The Fe numbers were very low and the drivability is so much better with the lower viscosity compared to the SAE30 or a XW40, especially with the start/stopping on the tougher trails.

I have also been around 4.0's my whole life and have never had or heard of an oil pump failure......
BUT it would make sense and could cause lifter tick with lost pressure, at the same time I would think your oil PSI gauge would display a change in pressure that would effect lubricating your lifters. I also understand mechanical parts loosing efficiency with wear (it is a gear typr pump) and using a heavier oil would probably increase oil pressure and quiet a tick caused by less oil pressure.....

I was always under the impression that the tick was related to the surface mating between cam and lifters (flat tappets)
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Originally Posted By: dlundblad
Yet another 4.0 oil thread.. I want her to get a good daily dose of zddp.

Yes there are many threads about this subject, but I am a firm believer that the 4.0 is a very unique engine and not all of them act and sound the same way.

Ive been running M1 5w40 TDT synthetic for about the last 50x miles in my engine which has 150x total. Its a 2003. About 15x miles ago, she developed a slight lifter tick. These engines are notorious for it. It would come and go, but be more noticeable on cold Indiana start ups. I would normally just let it warm up like a diesel truck and it would be good to go so I lived with it. Due to availably, I had to use 10w30 M1 HM. (I believe I had stated in another thread I used 5w30 HM, but I found the bottle today.. it was 10w oil.) And well what do you know, the tick has almost gone away. It is present for a few moments on startup, but that's about it. While most people think the 4.0 needs a thick HDEO, I feel mine likes the thinner stuff.

Questions:

Is the thinner oil quieting down my lifters or is it just in my head? Maybe the HM flavor has different detergents than the TDT? My instinct tells me it would have less than the TDT only because diesels are pretty dirty.

Ive read multiple places that the M1 HM oil contains ether (seal conditioners or " seal swellers") Would that create an issue on my RMS? I actually called M1 and the "technician" said most of their oils already contain seal conditioners. But this was also the guy who recommended I ran 5w 50 synthetic oil.. I saw a 550+ horse mustang at a car show that wanted that stuff. I doubt that's what my jeep needs.. haha

How about the European 0w40 M1? I just worry the oil wont stick to the internals properly. or just be plain too thin. I checked the M1 site and the viscosity, cSt (ASTM D445) @ 40 degrees Celsius is 75 for the 0W40 the 10w30 HM is 78.1 @ 40 degrees Celsius. Not too sure on what those numbers mean exactly, but the 0w40 almost seems a tad bit thinner.

Or should I just drop M1 all together and find something else? Id like to stay on synthetic. There is also the RT5 which is the 10w30 synthetic blend. Im a little hesitant about the blend part.. Id rather it be full synthetic. And plus it also says on the back on the bottle that its compared to RT 5w40 oil so it sounds like its just like the M1 TDT. I want to stay on a thinner oil.

Im currently running the M1 filter as well, but im planning on going to Wix next oil drain.

Thanks


In your climate - Dino.....VWB. Synthetic....ST Syn or Amsoil. On all 3 oils, have gotten great UOAs on our 4.0.

You didn't mention what your driving habits are, but ST or VWB can easily go 5k or 6 months of in town driving.
 
I drive about 250 miles a week perhaps? 80% of that is highway miles at about 65-75 mph.
 
Originally Posted By: dlundblad
I drive about 250 miles a week perhaps? 80% of that is highway miles at about 65-75 mph.


With that kind of driving you would really benefit from extended drains with Amsoil.

I have taken our 4.0 up to 12k, with good tbn remaining. Filtration was the reason we didn't go further, so if you go this route make sure to use a high mileage filter (like M1, Amsoil), or a solid filter like Wix changed every 10k. Try 7500, leave it in and sample for a UOA, and go from there.
 
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I'm pretty sure someone on here posted a thread of their jeep 4.0 that had used PYB religiously and that engine was immaculate and was said to run super smooth with that oil. I would go with PYB.
 
Originally Posted By: Kuato
Originally Posted By: dlundblad
I drive about 250 miles a week perhaps? 80% of that is highway miles at about 65-75 mph.


With that kind of driving you would really benefit from extended drains with Amsoil.

I have taken our 4.0 up to 12k, with good tbn remaining. Filtration was the reason we didn't go further, so if you go this route make sure to use a high mileage filter (like M1, Amsoil), or a solid filter like Wix changed every 10k. Try 7500, leave it in and sample for a UOA, and go from there.


I have thought about it but honestly amsoil annoys me. Seems like the first thing a hillbilly kid does to his hillbilly truck is add an amsoil sticker to the rear window.

They do make a 5w 30 diesel oil though. Definitely something to look into.
 
Originally Posted By: dlundblad
Originally Posted By: Kuato
Originally Posted By: dlundblad
I drive about 250 miles a week perhaps? 80% of that is highway miles at about 65-75 mph.


With that kind of driving you would really benefit from extended drains with Amsoil.

I have taken our 4.0 up to 12k, with good tbn remaining. Filtration was the reason we didn't go further, so if you go this route make sure to use a high mileage filter (like M1, Amsoil), or a solid filter like Wix changed every 10k. Try 7500, leave it in and sample for a UOA, and go from there.


I have thought about it but honestly amsoil annoys me. Seems like the first thing a hillbilly kid does to his hillbilly truck is add an amsoil sticker to the rear window.

They do make a 5w 30 diesel oil though. Definitely something to look into.



Heh heh....I use the oil and throw the stickers away.
 
Honestly I'm just waiting Delvac 5w 30 synthetic to be available here. I can buy it online from this place in Turkey but shipping would kill. Lol.
 
Originally Posted By: dlundblad
Honestly I'm just waiting Delvac 5w 30 synthetic to be available here. I can buy it online from this place in Turkey but shipping would kill. Lol.


Devlac has a product that's a 0w-30 hdeo. It's called devlac elite 222. Its a very interesting oil and the grade itself lends it to being great in many gasoline applications.
I bought 3 gallons a few months ago. I've managed to find a supplier that can get 5 gallon pails.
I think once I get through my stockpile I'm going to use it in everything I own. I'm not a Mobil fan whatsoever but this oil is something special.
Its and hdeo so it should be fairly shear resistant and fuel dilution isn't as taxing with it in comparison the pcmo's.
I'm going to be using it in my bikes next year. I'm anxious to see how it holds up in my Harley,and the shadow.
 
The only Delvac I've seen is 15w 40 at Walmart.

** Clevy I see where you're from. You skunk. You get the good stuff! :p
 
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