Saiba Samurai

So I just purchased a 1986 22RE 4Runner and I want to give it a good tune-up. I've always been a fan of Mobil1 synthetic oil and I was wondering what you guys thought about a swap to synthetic. There's no oil leaks on the engine but it is burning some oil. I'm planning to do a compression test as well, I'm hoping it's the seals.

Anyway, as for the synthetic oil... I did a search and it doesn't seem like there's a huge group of people saying don't do it. What I can't seem to find is what weight people are using for these engines.

Jay351

how many miles?

When you switch to synthetic, it cleans out most of the gunk in the motor. This gunk can be blocking leaks. Once the gunk is cleaned out by the oil, there is a possibility of oil leaks....

Its up to you, I switched to Amsoil synthetic with over 100,000km on my rebuilt motor..

I use 10w-30.

Saiba Samurai

254k on the motor.

Jay351

... thats a little much.

Its your call if you want to risk it. Synthetic oil will probibly just be a waste of money at that kinda mileage..

Saiba Samurai

So what weights do people use respectively?

Synthetic:
Regular:

24Runna

10W-30 Mobil1 HM
10W-30

LITLRED

I'm running 5w30 Royal Purple Synthetic with about 4,000 mi on a complete rebuild. Hot idle oil pressure is about 13lbs.

AZkid

i think most people run 10-30

but altitude and other things effect what kind people use

then theres the people who just grab oil :p

Nogarage

For what it's worth, I've long been under the belief that synthetic is never "100 percent" synthetic - it's a certain percentage of long chain synthetic polymer molecules suspended in "short chain molecule" conventional oil. But even so, it has superior qualities in every area, especially service life and thermal protection. Rregardless of the mileage on my vehicles I've always included a quart of synthetic oil in the engine (manual trans 22RE= 3.5 quarts Castrol High Mileage 10W-40, 1 quart Name Brand Synthetic 10W-40 or straight 40). Long time ago in a 1976 Dodge Colt (Mitsubishi 4 cyl) an old coolant hose broke, spraying steam nicely from under the hood. I shut off the motor and pulled over ASAP. Got towed and the shop that repaired it told me the radiator was bone dry. In my opinion it was the synthetic in there that kept the motor from melting.

OutlawMike

Oil weight is mostly determined by ambient temp and bearing clearances. If it is colder (not California cold, like, North Dakota winter cold) you want to run a thinner multiviscosity oil, like 5W30, so the oil will flow at startup, but have the same relative viscosity at operating temp as a 10W30.

If you have a higher mileage motor that has the bearing clearances opened up due to wear over time, you may find that the thinner oils do not build much pressure, as they piss out of the larger clearances. So, you may want to run a 20W50 if you find that you have low oil pressure on a high mileage motor.

As for synthetic, for a newer or rebuilt motor with fresh seals, I swear by the stuff. I did my Mechanical Engineering internship at Allied Signal Turbochargers (used to be Garrett / Air Research). The 100k mile dyno simulations on turbocharged motors with conventional versus full synthetic are jaw dropping.

But, with an older motor with high miles, it may not be worth it, mainly from a cost / benefit standpoint. With a brand new motor, you do it to get 300k out of the motor. With an older motor, you are almost there anyway.

bigtrucknwheels

try a synthetic blend (50% Dino/50% Synthetic). It is specially formulated for what you want to do. As Jay said, the high mileage switch over to a full synthetic will only result in excessive development of new leaks.

crafthorse

I like the semi syn blends, the proven performance of a conventional oil teamed with the most advanced engine wear properties of Syn. I think that is the best route. I use 10-30 in southern South Carolina.

Matt16

I've run 15W40 and 10W30- hard to tell if one worked better than the other as my engine never melted down. I'm in Vancouver, BC.

I'm running Mobile 1 Synthetic, but I used to run Amsoil. Amsoil was hard to find and pricey, but just scrubbed the inside of the engine. It looks brand new, just-rolled-out-the-doors when I pulled the valve covers after running Amsoil. I don't think the Mobile 1 was able to clean that well, but I'm sure it can keep it that clean. I can't justify spending a tonne on a long-life motor oil in a 4wd, because the engine is more likely to see contamination (water, dust) than in a road-driven car. I work on my truck a lot and so the fluids are drained from time to time.

bob200587

This is fantastic information. My engine's oil pressure is low for the aforementioned reasons and I usually run Mobil 1 10w-40 in warmer months, and 20w-50 if it gets really cold.

tj884Rdlx

i've owned about a dozen vehicles with over 100k miles when i bought them.

i currently use valvoline high mileage in my 88 4r w/ 231k mi. i prefer 10w40 in summer and 10w30 in winter. i tried the 20w50 first, but it sounded a little valve loud at start up, so i dropped down to 10w40. i prefer the hi-mile stuff because it includes some seal conditioners to stop some minor leaks. of course you have to continue using it to maintain the swelling in the seals. my rear main leaks, but i have managed to slow the leak from what it was when i got it.

i prefer full synth for newer motors. like from the turn of the century forward. older cars, i prefer dino oil. trucks like ours were not designed to have a 10k interval on oil, and engine tolerances are engineered to an extreme degree now. (0w20? wow) i like knowing i have new blood, new filter, every 4k.

whichever you choose, make sure you check your level every gas fill up. it's just a good habit to develop. y'never know when some 20yr old part may fail - and the first indicator could be on the dipstick.

tj884Rdlx

20w50 if it gets really HOT. 10w30 for cold. 5w30 if it gets REALLY cold.

first number is weight at 40c. second number is weight at 100c.

bugs1961

Mobile 1 15w-50 in the summer and 10w30 in the winter (in Anchorage)

Adh007

I'm a big fan of the Shell Rotella-T synthetics. 0w30 or 5w40. I started using them in my motorcycle and now I put it in everything.

But it is true, if you put 0w30 synthetic in a high mileage engine and you'd better tape some cardboard under it to catch the drippage.

Tubbyfatty

Isnt the Rotella T for diesels? I was watching horsepower tv one day and they were using it as a break in oil cause it has alot of zink and forphorus (spelling) in it, then they said "dont run it for long in a gas motor because it will create alot of sludge".

As for oil, I run a synthetic blend of valvoline max life 10w30 when I can get it cheap, and a toyota filter (i love haggling with the parts dept.)

Nogarage

Try Huggies disposable diapers. LOL!!!