yarmish

do any of you guys run mobil-1 in your 3.slow..i am up for an oil change.the motor only has 40k on it.what should i use for oil??

thanks

eric-the-red

I ran Mobil-1 in my 3.0 when I had it. Mine had about 180,000 km on it when I started using the Mobil-1 and it actually reduced my oil consumption. I used the Higher Mileage 10W30 grade.

MarkieMark

i wanted to run Mobil 1 Synthetic but my t4r leaks a little. i just stick with the Mobil 1 Clean High Mileage Oil. i might go sythetic blend for a while then switch to synthetic. if it leaks more i'll just stay with what i usually use.

Astroluc

QuakerState 4x4 10-30 full synthetic for my 2.7

Ironmike4x4

Go ahead and swithch it, you should be fine. If regular oil doesn't leak in it then you should be fine, anymore questions then go to Bob is the oil guy I've been running M1 in mine ever since I got my 4Runner and go for 6,000 miles before changing it, but changing the oil filter at 3k.

MarkieMark

good news guys! lol im switching to M1 Synthetic. i checked where the leak was coming from and it wasn't from the engine. it came from the transmission. might be the gasket from the last tranny fluid change.

90

Sorry if this is OT... I've heard once you go to synth you should stay with it, what's the reasoning there, anybody know?

jimbo74

it keeps consistency on the oil seals and otehr parts

91T4R

A friend of mine brought up what seems to be a good point about switching to synthetic on a high mileage engine. Lemme run this past you guys, and you tell me if it sounds like it holds water to you.
He said that over time, many seals will start to erode, and that normal engine oil will often get into that hold and kind of gum up, sealing it. Then, you switch to synthetic, which cleans better, and it can remove that gummed up oil, exposing the leak that was really there all along, but clogged. Sounds logical to me, but have any of you seen or heard of this happening? If so, I may replace the seals on mine before switching. Thanks.

Robert

90

This is probably a fluke occurance, but before I changed to synth the truck was up on a hoist, and I noticed a leak from the rear of the engine. The mech agreed with me thinking it could be rear seal ( sigh ). But after the oil change there's no more leaking. Kind of contradicts what you were saying 91T4R, but who knows...

DaveInDenver

There's some truth to this, although it's not really because of high miles specifically. A seal leaks when it goes bad, no matter what oil you're using. If it does not leak with conventional, it probably won't leak with synthetic. But it's true that synthetic oil does not evaporate as easily as conventional oil. It's this resistance to evaporation that is a major reason to use it. The engine is hot and oil will be evaporating inside and this is partly what causes sludge, sort of like when you boil something to reduce it and it gets thicker. But at the same time, burnt conventional oil can build up to an extent in places with small clearance, like seal interfaces. But I think since modern oils are better and cleaner than just a few years ago that it's probably not really a huge effect. But, sure, it's possible that synthetic will clean sludge and gunk out of the engine and can leak because of this cleaning effect with marginal seals. It's sort of important to say, though, that if the seal is marginal and the only reason it's not leaking is it's clogged with gunk, it's really already gone bad.

sandcrawler

since your engine only has 40k on it i'm sure you're fine switching to synth. though i hear a lot of people recommend something other than mobil 1.

DaveInDenver

I use Mobil 1 0W40 in my 177K old 22R-E.

91T4R

Yea, I realize that. I was just wondering if anyone had experience where a change to synthetic uncovered an existing problem that was covered up by something else. Thanks for the input, guys.

Robert

fo_runner

I use Vavoline Syn Power. This oil is pretty cheap, and it's almost the same thing as Mobil1.

yarmish

i see some guys are using 0w40..should i stick with 10w30?

DaveInDenver

I run the 0W40 mostly because of the winters. I park my truck in cold spots (for example, a morning start on Berthold Pass can easily be -10F, synthetic fluids and an Optima are essential) overnight skiing trips. If it wasn't for that, I'd use 10W30 or 5W30 in the winter and 10W40 in the summer. But 10W30 is supposed to cover the same range as 10W40, at least according to the owner's manual. It depends IMHO on where you live and what you do with the truck. Along with the very cold temperature starts, I also drive in the mountains, which means extended periods at relatively high RPMs. Like a pull up a pass might mean 3700 or 4000 RPM sustained for 15 minutes. I just feel better with a heavier weight oil in those cases. I'm probably being over cautious, but I do notice a major difference with 0W40 on cold temp starts.

LittleRedToyota

i like mobil high mileage synthetic blend personally. way cheaper than pure synthetic, but seems to clean better than regular dino juice.

switched to it from dino juice at about 85,000 miles...did not cause any leaks.