Preferred Oil / Weight

[Butchershop]

Ok guys, what is your preferred oil to run in these older high mileage engines?

Brand, weight, filter, etc. Any unforeseen warnings? Advice? Thanks.

[Eagle]

I run Castrol Syntec -- full synthetic. Oil filters are Purolator.

 

For oil weight, the factory called for 10W30 or 10W40. I ran 10W40 up to around 200,000 miles. At that point, the highway pressure was a little lower than it used to be (still well within factory spec), so I changed to 5W50.

[Butchershop]

Thx. Any issue changing over to synthetic if its not been used before? Not sure what the PO put in there.

High mileage synthetic is what I'm thinking.

[ParadiseMJ]

Not for me. I started using full synthetic...Mobil 1 10/30....a few years ago on my XJ. All the worries about it revealing leaks did not materialize. I especially like the longer change interval. I usually change filters at ~3-4K (NAPA Gold) and oil at ~6-7K. My internals are squeaky clean. XJ is at 237K, MJ is at 190K

 

I had leaks before, and they needed to be addressed anyway. I'm just a little more vigilant now. When I started building the MJ I just started it off with Mobil 1 10/30 right off the bat. There are no extremely cold temperatures here

 

I can honestly say that I have no visible leaking or seeping anywhere. My wife doesn't even mind when I park the MJ in the garage. The XJ has a few small drips, but I emphasize small. Nothing that ever leaves more than a drip drop from time to time.

[mountainman]

Valvoline 10/40. I would say 10/30 us just too thin for any engine over 100k miles. I run the mopar filter and change it between 3 and 5k miles. If it starts to not look clean.. byebye. In summer when i went on a big overloaded road trip i put in a qt of lucas stabilizer and it seemed to really like that alot. Oil pressure was more consistent overall despite it being 110 out and me going 85 the whole way with the AC on high. :yes:

[jimoshel]

Anything over 350K I run straight 50W. No filter. I got tired of them plugging up all the time. Everything else, synthetic 10-30, MoPar filters. Picked up a carton of them at an auction a couple years ago. Trying to get them used up.

[mvusse]

Mobil 1 high mileage, it is about the only readily available oil that is still SL. Everything else is SN and contains no ZDDP anymore. Only other alternative would be 4 stroke motor cycle oil as most of those are SJ.

 

As far as weight, 10W30.

 

Purolater Pur-One filters.

[rejeep]

regular dino juice...

anything else and your throwing money away... its more important that it gets changed than what you put in it...

 

only todays modern engines need full synth oils...

 

Wix filters (or house brands made by WIX) .. all the rest are crap

 

these aren't opinions these are industry facts..

[SW86]

delo 400 and WIX filter everytime. sometimes ill even throw in that engine restore stuff just for the hell of it.

[ComancheKid45]

Mobil 1 high mileage, it is about the only readily available oil that is still SL. Everything else is SN and contains no ZDDP anymore. Only other alternative would be 4 stroke motor cycle oil as most of those are SJ.

 

As far as weight, 10W30.

 

The Quaker State Defy 10w30 oil is also only SL rated to my knowledge. Amsoil has a line of 10w40 out that is specifically designed to SL and prior specs as well.

[mountainman]

The zddp content only matters if youre breaking in a new cam anyways. These ancient engines with 9 million miles on the cam and lifter faces, the surfaces are so hardened that your not gonna hurt anything by having less zinc in the oil now. Thats another industry fact.

Same as 10/30 is so watery... its just about useless in anything other than these tight tolerance brand new engines. Its only suggested in this country for EPA laws and to hit mileage/MPG ratings.

For example... the honda s2000 (i build them for much of my living), honda only recommends 5/20 and 5/30 in this country. To hit the stupid mpg standards. A 240 hp 9000 rpm 2.0 puts much more stress on the oil than 10/30 can handle. So in every other country the engines are recommended to get 15/40.

HMMM,,, interesting ay.

 

So as i said before, not to harp on anyone but i wouldnt put 10/30 in one of these 4.0s if you payed me. Its just too thin. Youll see a torque increase and a quieter engine all around if you move to the next weight up.

Now if you live in alaska where the engine never warms up... then yeah i can see running water oil cause its gonna stay quite thick in that climate and the thicker oil is just gonna resist flow on sub zero startups.

[danbyrambler]

been using Shell Rotella 15W40 in high mile engines for a long time - - Diesel oil - extra adds - - - Also comes in 5 &10W - - - Sold just about everywhere inc Wal Mart

[88mjgilley]

i have ran rotella 15/40 and a bottle of lucas in every 4.0 ive had it helps keep the valve train noise down and the oil pressure up been doing this for about 8 years now and have never had any internal issues ps my 4.0s normally live on the rev limiter also :)

[mvusse]

i have ran rotella 15/40 and a bottle of lucas in every 4.0 ive had it helps keep the valve train noise down and the oil pressure up been doing this for about 8 years now and have never had any internal issues ps my 4.0s normally live on the rev limiter also :)

 

From your user name I assume your 4.0 is an 88?

 

The Renix 4.0s don't have a rev limiter.

[danbyrambler]

MY '89 DOES - - - IT'S CALLED THE FLOORBOARD

:thumbsup:

[cruiser54]

Jeep Engine Oil Viscosity

This was taken from pages 82 and 83 of the 1989 Chrysler/Jeep owners manual.

Selecting Engine Oil Viscosity

When changing or adding engine oil select the proper grade by using the chart on the following page. Select the grade that corresponds to the ambient temperature range you expect to encounter before your next oil change.

30*F to 100*F+ 20W-40 or 20W-50

0*F to 100*F+ 10W-30 or 10W-40

-20*F to 60*F 5W-30

 

Rotella 15-40 and Wix or Napa Gold for me.

[88mjgilley]

ive had around 15 xj and mjs and trust me i know my mj doesnt have a rev limiter it screams at 6500

[mountainman]

Jeep Engine Oil Viscosity

This was taken from pages 82 and 83 of the 1989 Chrysler/Jeep owners manual.

Selecting Engine Oil Viscosity

When changing or adding engine oil select the proper grade by using the chart on the following page. Select the grade that corresponds to the ambient temperature range you expect to encounter before your next oil change.

30*F to 100*F+ 20W-40 or 20W-50

0*F to 100*F+ 10W-30 or 10W-40

-20*F to 60*F 5W-30

 

Rotella 15-40 and Wix or Napa Gold for me.

 

Very nice. Good to see that from factory. i have considered 20/50 but i would only go that route as a bandaid for a very high mile engine with oil pressure thats below where i wanted it. The guy i got my truck from is into old indian motorcycles, heavy equipment and old vws. So since he got this MJ he always changed the oil with straight 40 wt. Which cracked me up cause thats NOT the oil i would ever put in it. But it has enjoyed a "clean oil" life and is in great shape. He changed the oil pump and sender cause he got scared as the oil pressure kept going UP after 150k. lol! He thought there was something wrong.

[huck731]

Anything over 350K I run straight 50W. No filter. I got tired of them plugging up all the time. Everything else, synthetic 10-30, MoPar filters. Picked up a carton of them at an auction a couple years ago. Trying to get them used up.

 

how do you run no filter? I use rotella 10w/40 and k&n filter in every daily driver vehicle I have had for 3 years now and no issues noted to date.

[danbyrambler]

Very nice. Good to see that from factory. i have considered 20/50 but i would only go that route as a bandaid for a very high mile engine with oil pressure thats below where i wanted it. The guy i got my truck from is into old indian motorcycles, heavy equipment and old vws. So since he got this MJ he always changed the oil with straight 40 wt. Which cracked me up cause thats NOT the oil i would ever put in it. But it has enjoyed a "clean oil" life and is in great shape. He changed the oil pump and sender cause he got scared as the oil pressure kept going UP after 150k. lol! He thought there was something wrong.

 

Your trucks PO wasn't off base using 40wt - especially so considering he was into air cooled v dubs & motorcycles - assuming he too lived in NM or another normally warm part of the US - - - - The factory info recommends 40 and 50 BASE oil for the warmest ambient temperature range and 30 BASE for the other two - - - the 2nd number in a multi vis ID is the oil base from which it's made/formulated & roughly corresponds to straight weight classification - - - - The 1st # in multi vis ID indicates how the oil will flow at start up - - at the start up temperature-whatever it may be - - -Operating temperature is another thing - - - 210F/thereabouts has been considered normal OT for some time & all W30s flow the same at that temp - - 0W30 5W30 10W30 all have the same viscosity at 210F - - - 10W40 15W40 20W40 will flow the same as a 30 base at 210F but have to be around 220F to do so - - - 20W50 ditto except in the 230/240F operating range - Thus you'll see 50 BASE recommendation for air cooled, heavy towing, warm climes & such - nothing wrong with straight weight except for maybe a little harder to find - - I read where some like racers, boat & aircraft prefer/specify it because no viscosity modifiers - - - Anyway,go by the 2nd # if you want more oil p for bearing clearance, op temp, whatever - - - - As an aside, just to stir it a little more, the Volkswagen flat 4, legendary for its durability - did not have an oil filter - not until sometime around 1972 IIRC - - - :thumbsup:

 

We build them good in Germany, eh Heine?

[huck731]

well they did have the screen on the bottom of the engine case which acted as somewhat of a filter.

[cruiser54]

well they did have the screen on the bottom of the engine case which acted as somewhat of a filter.

 

Ever seen one? Like your screen door. Not worth much as a filter...

[HOrnbrod]

Rotella is good, but I prefer Chevron Delo 400 LE 15w40. Year round. It meets the API classification SM for older engines, and still has a 1300 ppm zinc count, unlike Rotella, and is one of the few motor oils that still do. Higher zinc content is beneficial for our flat tappet 4.0 engines, whether during cam break-in or maintaining longevity because it reduces the metal-to-metal friction no matter what the age/mileage. Chevron Delo 400 is a diesel spec motor oil and I've been using it for years in my Jeeps, but especially in the stroker with a mild cam.

 

Filters? I use the extended length Purolators.

[Eagle]

- nothing wrong with straight weight except for maybe a little harder to find - -

 

Au contraire.

 

There is a problem with straight weight oils. They don't flow well when cold, which can result in dry bearings and dry cylinder walls when the engine is started in cold weather. I'm old enough to remember when all we had was straight weight oils, and multi-viscocity was considered a modern miracle when it was introduced. And engines last a LOT longer with it. 250,000 to 350,000 miles is nothing special these days. In the days of straight-weight oil, if an engine made it to 100,000 without a major tear-down and rebuild, THAT was considered a miracle.

[mvusse]

Your trucks PO wasn't off base using 40wt - especially so considering he was into air cooled v dubs & motorcycles - assuming he too lived in NM or another normally warm part of the US - - - - The factory info recommends 40 and 50 BASE oil for the warmest ambient temperature range and 30 BASE for the other two - - - the 2nd number in a multi vis ID is the oil base from which it's made/formulated & roughly corresponds to straight weight classification - - - - The 1st # in multi vis ID indicates how the oil will flow at start up - - at the start up temperature-whatever it may be - - -Operating temperature is another thing - - - 210F/thereabouts has been considered normal OT for some time & all W30s flow the same at that temp - - 0W30 5W30 10W30 all have the same viscosity at 210F - - - 10W40 15W40 20W40 will flow the same as a 30 base at 210F but have to be around 220F to do so - - - 20W50 ditto except in the 230/240F operating range - Thus you'll see 50 BASE recommendation for air cooled, heavy towing, warm climes & such - nothing wrong with straight weight except for maybe a little harder to find - - I read where some like racers, boat & aircraft prefer/specify it because no viscosity modifiers - - - Anyway,go by the 2nd # if you want more oil p for bearing clearance, op temp, whatever - - - - As an aside, just to stir it a little more, the Volkswagen flat 4, legendary for its durability - did not have an oil filter - not until sometime around 1972 IIRC - - - :thumbsup:

 

I might be mistaken as I do not work in the oil industry, but I always though multi viscosity oils were made from stock with a viscosity of the first number, using friction modifiers to act as the second number at 100 degrees Celsius (about 210 Fahrenheit). So a 10W30 is made from 10 weight oil with viscosity modifiers to make thin out only as much as 30 weight when hot.

 

Multi viscosity oils still thin out as they get hot, and still do so as a logarythmic function of temperature, but with a flatter curve than a single weight oil.