Just bought a '95 4Runner SR5 4x4. It was my neighbors (who is a BMW mechanic) girlfriends. She was the second owner.

Its got 158,xxx miles on it and has never been ran on synthetic. I was thinking about switching over but from what I've heard you can do more harm than good switching. I've been told that if you switch a high mileage vehicle to synthetics then you may knock a bunch of crap loose in the engine and mess everything up.

Has anyone had this problem switching over?

 

This is an endless debate.

I bought my 4runner stock with 240,000 miles on it, and i switched to synthetic at like 245,000. Didn't have any leaks associated with changing over.

Google "bob is the oil guy" . I think that is what the site is called and it has a ton of good information on oils.

 

If your worried about the engine at least switch over your transfer, tranny, and diffs. There's a lot of different variables on your engine. If it had the oil changed on schedule it's entire life so there's no sludge and it currently has no leaks I would go for it. If you already have some leaks chances are they will be worse with synth.

 

Yeah I bought a 97 with 224 miles on it and it had no leaks etc but I've decided to use dino changed every 3K since I'm planning on installing a new motor in about 50K miles. I figure why drop 800 bucks into a motor with 280k on it for a water pump, timing belt, cam and crank seals, and associated belts and hoses. If I was going for 400K and beyond then the synth would make more sense. I've read and read and read about this and no one really agrees.

 

After doing a lot of research and unbiased tests, I use Valvoline Maxlife synthetic blend. It isn't the best oil out there, but the cost to performance is great. It beat out most blends and even some fully synthetic oils that cost 3 times as much. If you want to spend more you can get Royal Purple or Penrite which did better. But at $14 for a 5 qt jug at WalMart, the Valvoline beat out Mobil 1 and many others.

 

ha, i get mobil 1 for free.... yet its only people at my shop that can get it free. sorry.

 

The mechanic I bought to truck from has been running 20w-50 in it and says that the thicker oil helps the engine run easier.

Any reason why I should or shouldn't keep using this oil?
The truck doesnt leak any oil now and it doesnt use any oil. Is this because of the thicker oil and an indication that it might have leaked at one point?
Does the mechanic suggesting thicker oil mean that a switch to synthetic would be bad?

Edit: I also live in florida so the engine heating the oil isnt a problem.

 

I've never heard anyone say that thicker oil makes the motor run easier, if it did I'd pack mine full of 90 weight and run the crap out of it.

The owners manual will tell you what weight to run depending on the temp. Just as an FYI I bought an 86 that had 171,000 on it and switched the motor/tranny/t-case/diffs to synthetic and never had a problem. I'm about to do the same thing on an 89 with 216,000 on it and feel confident that it won't leak either.

 

The oil cap says 10w-30 but I asked him why he was running thicker oil in it and he said because its a high mileage vehicle and that since things are most likely worn down in the engine it helps fill the void.

I dont know much about engines so I dont know if his logic is justified but with him being a mechanic I trust him.

If I do switch to synthetic and things start to leak Im under the impression that there is nothing I can do about it except replace the seals. Is there any other way to reverse the effects of synthetic?

 

Just because hes a mechanic doesnt mean he know what hes talking about. Alot of these old school mechanics think that if you run thicker oil it fills in the voids of worn parts. The truth is it creates problems these engines are designed to run 10-30. Theres a reason that it tells you to run it there are so many small oil passages in a engine, when your running a thicker oil it takes alot longer for the oil to get through those passages and in turn causes wear to the engine. As far as running synthetic if your in doubt start by sunning a synthetic blend do that for a couple oil changes and keep a eye on it. If theres no leaks then go to full synthetic. but i would run the 10-30.

 

Is there a certain blend you would recommend over others?

 

I personally like Quakerstate, but Castrol is good to. more then anything when it comes to oil selection its all a matter of personal preference. you ask most people why they run the oil they do its because that's what their dad always ran or their grandpa swore by it. as far as full synthetic goes I would recommend Amsoil or Royal Purple I've see numerous tests and they always did the best.

 

My dad uses Royal Purple in his 96 F250 powerstroke. Hes got 300k+ on it so far and swears buy the purple. If I go synthetic thats what Im going to use.

 

Good choice. I'm running RP in the pickup right now and that's what I'll be running in the 4runner when I do the change.

 

Like I said run a blend for a few changes the thing with synthetic oil is the molecular structure is so much smaller. It will find those pinholes and leak. thats why I say run a blend and keep a eye on it. you may even find that you like the blend. and stick with it.

 

I run Synthetic Shell Rotella T 5w-40 in mine and it works great. doesn't leak really and it has decent oil pressure. oil has been cleaner the last couple of oil changes too since i switched it over.

 

I just noticed you were talking about a 3vze. My motors are both 22re's. I doubt it really matters but I didn't want to mislead you. I guess I should learn to read and understand the title before I jump in with some advice. Sorry.

 

I bought my truck with 92,000 miles on it, used dino oil until 150,000, then changed to synthetic. Never been an issue. I tore it down at 218,000 miles to rebuild after the infamous HG issue and it had ZERO wear on the cylinder walls; I'm talking the original crosshatching was clearly visible! Yes, I'm a Believer in synthetic oil....

By the way, I was using 20w-50 dino and when I changed to synthetic started using 15w-50 Mobil 1. I drive a lot of high-speed highway miles (130 R/T to work every day) & I like the idea of added viscosity when I'm cruising along at 80 miles per hour....

 

I was watching horse power the other day, they were using that for a break in oil, they said that if you use it too long it will create alot of sludge because its a diesel oil.

Im not saying you should switch or what not, im just telling you what i heard and watched.

If you wanna watch the episode its the one called "olds 455 dyno results", its on the spike website.

 

that's interesting, because the rotella T diesel oil is actually supposed to limit sludge build up and deposits because diesels have a lot of soot that gets into the oil.

I will look into it. thanks for the heads up.

edit:

http://www.shell.com/home/Framework?...drive_dpu.html

I know this is from the company, but it's something