Topic: Favorite Motor and Gear Oil.

[RT]

What's everyone's favorite oils and why?

[aka-justin]

I'm fond of standard Mobile engine oil for all my daily drivers and any standard gear/atf oil (Mobile when possible). Red Line MT90 did wonders in my 95' AX5 5 Speed, but pricey if you do constant mud/water encounters. When I had my RV - since it sat in storage and towed a lot - I'd run full synthetic Mobile engine oil.

Mobile just always held up better (performance wise) near to the end of my needed oil changes. All my other standard brands never seem to perform as well as long. For my diffs/trans/t.cases, I've never had enough experience to know much of a difference, other than running Red Line MT90. Engine Restorer always helped my high mileage vehicles too. Occasionally, I'll toss in some Lucas additives; no real reason other than word of mouth recommendations.

[chardrc]

we use mobil 1 in everything except the willys and my jeep get mobil clean 5000 because mine leaks to much and the willys needs thicker oil and gets changed too often for mobil 1 to be viable. Royal purple in the diffs and tranys for the new vehiculs as well. the willys gets a mix of mobil and locus gear oils. 

[Jeffy]

For the engine I typically use Mobile 1 for a few reasons.  The biggest is that you can usually find it anywhere and it's usually fairly inexpensive.  This time around I'm running Castrol Syntec though.

For gear lube, I usually go cheap.  Castrol or Penzoil or whatever.

[neale_rs]

Penzoil Synchromesh has worked well for me in the AX5.  Everything else, whatever name brand I can get at the time.

[jramey]

Valvoline or castrol in the engine. Just preference I guess lol, cheapest stuff at the time for diff fluid

[chrisfranklin]

Mobil 1 in the engine, Redline synthetic in the transmission and Mobil synthetic gear lube in the diffs.

[jfrabat]

Any brand synthetic for engine oil (typically Castrol Syntech), and the cheapest fossil oil I can find for the diffs (I change them VERY often, as they tend to get water in them with my type of wheeling).  For the tranny, Redline MT90 exclusively...

[RT]

So mobil 1 vs. valvoline.

[chrisfranklin]

...and Mobil synthetic gear lube in the diffs.

Only because I stay out of the water 

[chrisfranklin]

Emoticon looks like a "clean-head" Beavis getting ready to yack. 

Even further off topic, but where'd you find these, Jeffy?

[RT]

Only because I stay out of the water 

lol what water would I be be in......I like in New Mexico 

[dwtaylorpdx]

If you change the oil a lot it does not matter which one you use.

The correct viscosity is way more important than synth vs std in my opinion.

Pre 96 need XXw40 or XXw50 for best pressure control. (Stock bearing clearances...)
After 1996 they tightened up clearances to allow the thinner oil and better mileage,
Each generation has gotten tighter and running thinner oil.

Synthetics are by nature more immune to thinning out of spec.
They also tolerate much higher temperatures without coking in the engine.

If you want to run extended changes you need to run a premium synthetic.
Mobile 1 and standard castrol and valvoline are good for a couple thousand or so extra miles,
Amsoil, Royal Purple, Motul and a few others will run 12K in a lot of engines.

Myth and legend abound on this topic... :) 2 or more opinions per person allowed..

Dave

[JohnnyO]

Try a couple different oils, get Used Oil Analysis on each, and let that be your guide.  To distill the reams of information on www.BobIsTheOilGuy.com, Mobil 1 tends to show more iron in UOA's in most applications, as compared to other oils.  Jeep engines tend to show high iron regardless of what oil you use.  Therefore, plain Mobil 1 in a Jeep 4-banger or straight 6 is probably not a good match.  If I were to use Mobil 1 in a Jeep I would use High Mileage Mobil 1 even if the Jeep did not have high mileage.

Older engines with flat tappet lifters (non-roller) like oil with more zinc and SL and SM rated oils have less zinc so as not to contaminate the cats if the engine burns oil.  You can either use a zinc (ZDDP) additive or use a diesel-rated oil like Shell Rotella.  Most high mileage oils have a little more zinc (ZDDP) in them too.  I have Rotella T-5 10w-30 in the Jeep now and it seems to be using oil at a faster rate although it doesn't smoke.  It is likely that the higher detergents in the diesel oil cleaned the ring packs and more oil is getting by, but then it has over 150k on it too.  I will get a UOA soon, however that may be next-to-useless information because over the course of 3000 miles I will have added 4 quarts of oil to an engine that holds 4 quarts to begin with.  Next oil change I will put in Valvoline Max Life 10w-30, get a UOA, and see which oil the Jeep likes better.  Hopefully it will use less oil with the Max Life, that worked on my mother's Cadillac which does not have high miles on it.  Early Caddy Northstars are notorious oil burners.

In all of my family's vehicles where I have tested and compared different oils, Pennzoil Platinum always showed the lowest wear metals in the oil.  Not that Mobil 1 was bad, just that Pennzoil Platinum was better.  Also it costs a little bit less.  I'm just sayin'....

Used Oil Analysis is the only way to know for sure.  Anything else is just speculation.  www.blackstone-labs.com , costs $25.

Gear lube I use either Mobil 1 if I'm doing it myself or Valvoline if I'm being lazy and going to the the Valvoline Qwicky Lube.  Mobil 1 ATF in the t-case.

[RT]

Thanks guys, I ended up using rotella t-5 in my motor and the coastal 85-140 in my diffs and it really likes both