Lurker

Hello all,

I'm seeking a little bit of advice here. I bought my 1995 4Runner back in 2010, and after buying it I brought it over to the local mechanic to get a bunch of stuff done to it (ALL new fluids, new t-belt, etc.) Normally I change my own engine oil (and anything else simple, providing I can do it outside since I have no garage), but I figured since they were already replacing a bunch of other stuff, they might as well replace that as well. As it turns out I told them put in conventional 10w30, instead they put in synthetic 10w30. So for the last 20,000 miles I've been running Mobil1 Extended Performance 10w30.

Now, I've always been told that once you change over to synthetic you can't change back because it messes up with the seals. On the contrary, I've read on the internet that it doesn't make a difference. So I'm not sure what to believe, I guess it depends on who you talk to. Anyway, it seems like my 3vze has always tended to burn a little oil (I've talked to other 3.0L owners and they say it's normal), but it seems like it burns through synthetic faster. Lately my engine has developed an oil leak, I'm not too entirely sure where the leak is coming from and I haven't had much time to investigate it (on top of that it's snowy, cold, and I have no garage). I'm just wondering if the synthetic oil has finally caught up with the seals, it's a tough judgement call I guess without not being able to cite the source of the leak.

Anyway, I guess some of the questions I have are:
- is synthetic, in your opinion, really as good as they make it out to be?
- can I/should I switch back to conventional without jeopardizing any seals?
- am I correct on my assumption that my 3vze seems to burn through synthetic oil quicker than conventional, or am I just dreaming?
- how normal is it for an engine to go from having zero oil leaks, to a small 4 inch by 4 inch "puddle" every time you park it after it's been running? (I've had oil leaks before on other vehicles, but they seem to start of small and get bigger as time goes on if not fixed right away.)
- also, assuming I do switch back to conventional: are there any brands to stay away from, or ones you would really recommend? (I usually try staying somewhat frugal with my vehicle, but I definitely don't buy the bottom-of-the-barrel crap either, I kind of believe "ya get what ya pay for"...)

waskillywabbit

iTrader: (-1)

Why not just fix the oil leak?

:wabbit2:

Lurker

Well, whenever the snow melts and I have a place to work on it in a parking lot (assuming it's something I can access given the tools I have) I'd like to give it a shot. But one of the things I'd like to know is if it's worth keeping the synthetic in there or not... I'm 50/50 with the stuff, not sure yet if I like it or not.

ksti

x2 Find the oil leak, put some dye in it and re-check. Just because you switched to synthetic oil doesn't mean it caused a leak. Most guys here will have there own preference on what oil best suits there needs. The most important IMAO is cold start ups, thats where you get more friction and wear. Good luck let us know.

Lurker

Hey thanks a bunch for the reply! That never really crossed my mind until you mentioned it, in regards to this oil leak (the cold start-ups). My 'Yota didn't come with a block heater, and I'm too cheap to put one on there, but it would surely save a lot of wear and tear on the engine I'd imagine. Knock on wood, I've never had a problem getting it started in the winter without a block heater (even at -23'F straight air temperature last February... don't ask how, it just did! Yikes!) but I know a block heater would be an excellent investment. Ideally, I wish I could park it indoors... I think that would be good for the vehicle as a whole (not just the engine), but I'm not that fortunate right now, you never know how handy a garage is until you don't have one anymore.

mt_goat

4" puddle every stop is big enough to worry about. I'd look into fixing that ASAP.

I had a BMW that started leaking when I changed over to Mobil1, It might have cleaned some sludge out of a seal or something.

BMcEL

True group IV synthetics can shrink seals. Group IIIs have enough esters to prevent this. I'm running Rotella T6 5w-40 (group III) in my 255k mile 3VZ and all I have is a small valve cover leak that was there before I made the switch from dino. Synthetic flows better cold so I'd be hesitant about switching to dino if you're in a colder climate. I'd recommend a group III synthetic 0w-40 or 5w-40.

There is nothing wrong with switching from synthetic back to dino, just make sure you drain it hot to get as much out as possible. And don't switch back and forth all the time. If you do switch back to dino, Castrol GTX High Mileage and Valvoline MaxLife are both good dino oils with plenty of seal swelling esters.

ksti

Sorry to bump this, but I was wondering I just bought Castrol GTX High miliage 10-40 and noticed it said (Part Synthetic) on the bottle. Is this considered a Group III or IV ? I'm still confused, returned Castrol 5-30 yesterday. Weather doesn't get real cold in Calif. I have about 257000 on my rig.