Los Gatos?

I switched at 142k miles, I had a small leak before and it didn't get any worse. It was just the oil pan gasket and I had it replaced...no other leaks to date.

934rnr

My 93 4 runner's odometer says 242,080 miles but the engine has 158,000 m on it since it was done under the toyota block recall. Anyways I was running 10w30 oil with lucas oil additive I did the headgasket on it 1500 miles ago. I am now running 5w30 Castrol GTX now. The oil looks alot cleaner now most of the sludge deposits have gone from the engine I am about to change the oil again. I really think 3000 miles is a guideline if you change your oil every 2,000 miles I think it would greatly reduce sludge buildup and keep your block alot cleaner.

Highland Runner

I didn't change over to synthetic untill I had 190,000 miles. I have run three changes through it at 5000 mile intervals. The engine has never run better, and no leaks.
As far as letting and engine warm up, this has been argued back and forth. I do let mine warm up for 2-3 mins if the temp is below 30 deg. I have found the engine gets to operating temp in less time by doing this and that is what you're looking for.
I heard someone explain it this way. When an engine is idleing, the shafts are suspended on a very thin layer of oil. As there is load put on the engine, the shafts are pushed to one side or the other in the journals. If the oil is cold it can't be pushed into the journals to cushion the shafts twisting. It is always best to flow warm oil through an engine rather than cold. I also think the amount of fuel it takes to do this is minimal at best.
I am also in the fire department. The manufacturers of our trucks recommends idleing at startup. We have quick release exhaust removal systems on these trucks just so they can idle in the firehouse before leaving. This is with the truck bays being kept at 50 degrees or warmer.

ChickenLover

I switched to a synthetic 5W-50 at about 85K and haven't had any problems at all.

Edit: The rear main seal started leaking like crazy one summer day while pushing the engine hard on the highway. Switched back to dino and no more leaky.

Sunday BBQ

I have always used 10-30 on my truck and cars. I'm thinking of switching to Mobil 10-30 Synthetic. what do you think?

outdoorfever

if this tells you anything, i have 140k on my 90 4runner and just switched to synthetic at around 139k and i have been getting 30 more miles to the tank, this is including summer driving, no change in driving and some a/c. not good for the engine. hell if i care, i am saving money..sorta..lol

4-RUNNIN' FREAK

THE ENGINE OIL BIBLE
http://www.chris-longhurst.com/carbi...oil_bible.html
I had changed over to Mobil 1 in my 96 Grand Am, 2 months later, engine seized - I traced my last drive back over and did not see any oil on the ground anywhere I was, and I remember I just changed it for the second time with synth. and all was well for a few hundred miles, the it just stopped.
As for flushing it with the (0-whatever) I thought it would clean all the gunk that was sealing everything from the conventional oil being burned on?

From http://www.chris-longhurst.com/carbi...oil_bible.html

"A couple of words of warning:

If you've been driving around with mineral oil in your engine for years, don't switch to synthetic oil without preparation. Synthetic oils have been known to dislodge the baked-on deposits from mineral oils and leave them floating around your engine - not good. I learned this lesson the hard way! It's wise to use a flushing oil first.
If you do decide to change, only go up the scale. If you've been running around on synthetic, don't change down to a mineral-based oil - your engine might not be able to cope with the degradation in lubrication. Consequently, if you've been using mineral oil, try a semi or a full synthetic oil. By degradation, I'm speaking of the wear tolerances that an engine develops based on the oil that it's using. Thicker mineral oils mean thicker layers of oil coating the moving parts (by microns though). Switching to a thinner synthetic oil can cause piston rings to leak and in some very rare cases, piston slap or crank vibration.
Gaskets and seals! With the makeup of sythetic oils being different from mineral oils, mineral-oil-soaked gaskets and seals have been known to leak when exposed to synthetic oils. Perhaps not that common an occurance, but worth bearing in mind nevertheless. "

jahMcS

I gave my 90 the Royal Purple treatment, with 208700 miles on the engine. So far no problems, I also changed the M/T, T/C, and both diff's to the RP Gear oil. My 5-speed has never felt smoother. I'll post another message after 5000 or so miles, but I don't think it will start to leak.

nigeltufnel3

This article says that the automatic tranny must be fully drained before putting in synthetic. does anyone know if this is true as well for a manual transmission? thanks.

denverbikeguy

Running synth in my 101k-mile 4runner. I ran a synthetic blend for a couple changes before going full-synthetic just to make less drastic of a change, but it's just fine. Would recommend you use the amsoil engine flush before switching though.

Buddyman

Yes I changed it on my 97 4Runner with more than 110000 miles and it's been just fine for the last 35000 miles.

984RNR

That is most definately true

waskillywabbit

iTrader: (-1)

Don't think I've posted on this thread before, if so, couldn't find it...anyway...

I switched to synthetic in my 85 w/ a totally rebuilt "new" 22RE after about 5K miles (told not to until after "break in"), got about 7500 on it now.

I also switched to synthetic immediately when I got my 87 w/ a 22RE...it had 271K miles on the ticker. Doesn't leak a drop and runs like a top.

CoedNaked

I would make the switch to synthetic without any hesitation if I were you. It will give you a very mild fuel mileage increase, a mild performance increase, it will run cooler which will prolong the life of your engine currently. My truck had the switch to synthetic done around 140-145,000 miles. I lose about a quart to a quart and a half between oil changes currently (every 3000-3500 miles). I think considering I have nearly 170,000 miles on my truck, this isn't that bad at all. I bought my truck around 155,000 miles (know the previous owner personally) so I don't have anything to attest to regarding whether it was leakng when it had dino oil.

But all in all I wouldn't worry one bit and you can only benefit from making the change. Obviously you are probably on top of your vehicles maintenance as you are a Yotatech member and you have asked, so you are concerned, so I would imagine checking your oil every 2 weeks or so regularly isn't a stretch for someone such as yourself (assuming the oil was to leak a little but I doubt you'll have issues with it leaking more than your engine currently uses/loses oil). So make the switch. You'll be glad you did.

Tacotex

Went to Mobil1 10-30w on the 4R @ around 165K. After 8500 miles (6 months), oil use is about the same or less than with dino-a little over a quart. Running the 5-30w M1 in the Taco, too (after 5k break in). Both motors seemed to smooth out a bit with the synthetic, and it cuts the time I spend changing oil in half

FUZION

started off with mobile 1 fully synthetic since it was 0 miles, when i had my acura i had heard some guys say that it wasnt bad but after 100,000 the effects of synthetic were not noticeable.
:chicken:

phoenixtroy

ran 10w40 synthetic for a while till ~95K, switched to 0w Amosil developed a slow leak of about 2 .5" diameter drops of oil every 3 days, switched back to mobil 1 synthetic @ 110K.

Nyqill Junkie

The previous owner switched mine to full syn before I bought it [ royal purple ]. it had 95k or so and didnt spring any leaks. royal purple to me seems like $$$ overkill since cheap syn is better than any top doallr dino.. when oil change time comes around I'll use the best syn I can afford...

I read (and I see its kinda true) if you change the oil filter every 2k miles, after you switch over, it helps remove the loose sludge from the synthetics cleaning.
Ive changed my filter 3 times since I got the truck and the filters is always BLACK... but the oil in the dipstick remails like new oil.
its often overlooked that once a filter gets clogged the dirty oil bypasses the filter to keep the flow and pressure up and you in effect.... have no filter in use.

as for leaks, i'd have to say if you have a leak now youll have a leak after you go synthetic. if you have a dry engine your unlikely to pop a leak. my other little car I switched and it started to seep out of the valve cover, but stopped after about 4k.

as I read the syn does clean out "crud plugs" and may start leaks but as the gaskets /seals are exposed to oil again they swell and reseal...

i believe i read that on the amsoil site... thats a good site to read tons on synthetic oil properties.

Tacotex

11k on the 1st syn. oil change in the 4runner (nearly 180k on this truck now). No leaks and running very smooth. It even cleaned the dino varnish off the 1st 4" of the dipstick

kmchby76

my most recent experience, i switched to mobile 5000, and my runner started leaking really bad. i just switched back to valvaline high milage and the leak has slow considerably. unless you have a rebuilt, i'd recommend against it based on my experience.