OceanView

My 98 ES300 is leaking a bit more than usual.
I put in Synthetic at about 70K was ok til about 150K.
I wanted to put in conventional oil in hopes to slow/stop the leak til next year but wasn't sure if this could be a problem on the 1MZ-FE engine.

Thoughts?

WAES300

From what I understand, if an engine leaks, it'll leak regardless of whether the oil is synthetic or not. Though I've also read the total opposite..

RTIS250

iTrader: (9)

Its going to leak either way... so its not going to matter. I would investigate and fix the leaks.

gemigniani

A 10W-40 "High Mileage" Conventional oil will definately slow the leak for many years and miles. I know this from owning several vintage Toyotas. Most major oil companies sell "high mileage" types of conventional oil; e.g. Valvoline Maxlife, Pennzoil High Mileage, Castrol High Mileage and so forth.

OceanView

Hope you're right.
I just changed over to Valvoline Maxlife Synthetic Blend 10W40.
I was running low on oil and didn't want to just add oil.
Will report back my findings after putting some miles on the car and see if I notice any change.

jadu

iTrader: (42)

i switched from synthetic to regular oil on the mazda 50k miles ago.. engine has been fine

PlatES300

iTrader: (1)

changing oils won't fix the leak. When was the last time you changed the front and rear main seals? The rear one is usually the culprit as you can't see it. I would definitely look at that first. I've had 3 ES300's and it was always the rear main seal on 2 of them. I changed it out on every car after 100k miles when I did the tune up since everything was already out. You should also change out the intake plenum gasket as well since you have to take that out to get to the rear main seal.

OceanView

thanks for the info, I am planning on opening up the engine and checking/replacing any leaking seals & gaskets sometime later next year.
Still investigating what to do as I've never done anything like this in the past.
Is this a fairly doable project for a weekend mechanic?

PlatES300

iTrader: (1)

Not exactly an easy task because you have to take apart a lot of hoses and things, but if you take youre time, it shouldn't be too hard. If you're in doubt, then it's better to have a mechanic friend or someone who knows what they're doing there just in case. It took me about 2-3 hours to take everything out, clean it, and replace all the seals. Good luck with it.