help with oil-consuming 1MZ-FE

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I have a 2000 Sienna with the 1MZ-FE "sludger" motor. It now has 290,000 km with no issues - knock on wood.

My advice:

Change the PCV valve

Change the air filter

Change the oil and filter - use Maxlife, Mobil, Castrol or some other brand name high mileage oil. You can try something thicker but my van does not use much oil with 5W30 PP.

Give it a good italian tune-up - warm it up first by driving for 15 minutes. Then accelerate hard, reving to the redline, every green light and chance you get for at least 1/2 hour and down shift instead of braking to stop or when going down hill.

Top up the oil and then carefully track the usage - check the oil level in the morning before you start the engine to get an accurate level.

Pray.

Report back in a month or two.
 
Originally Posted By: Gokhan
Originally Posted By: garlicbreadman
going with a thicker weight is pointless, its obvious the motor has something seriously wrong with it. even if using a 40weight will bring it to 1 quart per 1000 miles, that is still very excessive

It's not pointless at all. 1 qt per 500 mile is not manageable but if it's less than 1 qt per 1000 mile, the owner can easily manage it.

Agreed, I've seen engines using a quart in 200mi drop to less than a quart in 2K mi by replacing the valve stem seals... I one doesn't mind adding the oil a engine can run 10s of thousands if not a 100K mi or more with bad stem seals... Not a serious problem, just generally a pain in asz to replace...
 
I would check that PCV valve.....The one on my 2003 Sienna screws into the rear valve cover.
You will need to remove it and look at the motor side of it......if it is clogged, then you found your problem.
I would eliminate the cheap & easy first.

I would also remove a couple of spark plugs and see if they are oil fouled.....
The front one are not hard to remove....rear spark plugs are a lot of work, at least on my Sienna......removal of the upper intake manifold is needed.

Be aware that the baffel under the oil fill cap may be coated with a rough black stuff.....FROM THE FACTORY.....as a sound deadening practice.
The one on my 2003 Sienna is.
THIS has often been mis-understood as being sludge.....it is not.

You could remove the front valve cover and inspect to see if there is sludge.
Under the rear valve cover will be a bit more dirty as that is where the air is drawn out through the PCV valve (fresh, clean air comes into the front valve cover).
Removal of the rear valve cover is quite a bit more work.....
If under the front valve cover is fine, then you will be fine under the rear valve cover.

At this point, you don't know if this is from consumption internal or leakage external.
It could be leaking only when you are moving.
 
I replaced the PCV valve yesterday. The old one was clean as can be (looked just like the new one). Definitely not original
smile.gif


I took the car to the dealer today, and explained the issue. They said it shouldn't be a problem to get it taken care of under warranty, they just wanted me to drive another 500 miles so they could document the oil consumption themselves, before the car went into the shop.

As a side note, the motor runs hot. Instead of the needle being 1/2 way up the temp gauge at normal operating temperature, it's 2/3 of the way up. Maybe the thermostat isn't opening all the way? I don't know. The dealer didn't seem worried, until I suggested that maybe the hot motor was making oil coke up. Just an idea.
 
We have a 2002 Avalon with the 1mz-fe engine that had 96000 miles on her when we purchased it. We are at 112000 miles now and use Pennzoil Platinum 5w-30 changed every 3000 miles. I check the oil level in it periodically and it never moves, in fact it is usually above full. You mentioned your temp gauge is 2/3 of the way on the temp range, this is unusual. In all the instrument clusters of the 1mzfe I have seen at operating temp, the gauge is slightly below the half mark.
I wouldn't try using a 40 weight oil because that is merely masking the problem. First and foremost pull a valve cover and check for sludge. Have you noticed your coolant level decreasing at all? I have read that is a sign of a potential sludge situation.
Sorry you are having issues with your 1mz-fe; they are really great engines and I have to say the smoothest V-6 I have ever driven. I am confident that once you diagnose and remedy the issue, it will give years of reliable service. Make sure you use an oil that tolerates heat well, particularly Mobil 1 5w-30 or Pennzoil Platinum 5w-30 (both meet the HTO-06 and GM 4718M heat tolerance specs). Keep us posted...
 
vt - I have the exact engine in an '02 Avalon. The PCV system is a likely culprit, but the engine design had narrow drainback holes in the head as well, just a FYI. You can replace the grommet and hose for the PCV system and really see if that helps. You got good info from the other posters, best of luck.
Those engines are really tough on oil.
You might benefit from OEM pcvs, and they are decently priced.
 
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update:

I've been checking the oil level first thing every morning, and driving the car as much as possible. This led to two discoveries:

Around town (usually 25-45, but up to 60 mph) it uses an immeasurably small amount of oil. I drove several hundred miles with no change on the dipstick. That's good!

On the highway (70-75 mph) it uses oil like that's it's job. It used at least 2/3 of a quart in 170 miles on the interstate (and still, no visible smoke). That's not good!

Hoping to get it into the shop next week.
 
Originally Posted By: ganseg
Why would it use more on the highway - I have a friend with the same symptom.


At 75 mph it runs at 3000 rpm. Cruising around town it usually stays below 2000 rpm. That's the only thing I can think of.


It runs the same temp on the highway as in the city. The more I think about it, the more I think the temp gauge is just reading screwy (my gas gauge reads high too) and the motor probably isn't running hot.
 
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update:

I checked the coolant temp, and it's in the 190-200 range when the car is warmed up. So the dash gauge is reading off, and the car isn't running hot after all. Good.

Also, over the last thousand miles I've confirmed that I use virtually zero oil driving around town (cruising RPMs under 2300) but my highway consumption is about 1 quart/200 miles (cruising RPMs between 2800-3000).

My *guess* is that at highway RPMs, oil is being pumped up into the valvetrain faster than it can drain back, so the PCV system is sucking it into the intake. But that's just a guess... does this sound reasonable?

Right now I have a quart of MMO in the oil, just to see if it helps loosen things up. I'm using PYB with an oversized Pure One filter. My plan is to pull the PCV hoses & make sure they're not clogged (I've already replace the PCV valve), then - and I really don't want to do this - take both valve covers off and assess the situation underneath, cleaning if necessary. How does this sound?

I found a few posts on other message boards from 1MZ-FE owners who had the exact same symptoms, and the remedy was to replace the valve covers. Presumably the right (rear) valve cover has a baffle for the PCV system that can get clogged with goo???
 
I had your situation twice, burning more oil at highway speeds. One was bad rings, the other valve seals. The car with the bad valve seals I added a quart of MMO and consumption was worse maybe because it was thinning the oil too much. Drained it about 500 miles later, not too dirty. Put in M1 High mileage and the oil was jet black at 1500 miles. When I changed the oil at 3k I was astonished at the goop that poured out. 3 changes later I was able to go 5000 OCI. Consumption was way down, but ultimately I changed the seals. you may want to try this oil, see if it helps clean any obstructions.
 
It burns more on the highway because of the higher rpm's.

My 1MZ-FE doesn't consume any measurable amount of oil in 7500 miles highway. I drive 100 miles a day, all highway. And take a >1300 mile road trip every 2 months.
 
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Originally Posted By: OVERK1LL
Pull the valve cover, maybe the oil drains from the head are plugging up?


Is there a specific tool used to clear the returns?
 
Originally Posted By: LeakySeals
Originally Posted By: OVERK1LL
Pull the valve cover, maybe the oil drains from the head are plugging up?


Is there a specific tool used to clear the returns?


No, typically just a bottle brush of some sort that fits. However, you'll know if you have an issue as soon as you have the cover off. If you are going to take it off, post pics!!!!
 
I'd make sure the stem seals are good, and get a look for sludge at the same time. If the seals are bad I'd replace them, and clean up any visible sludge. Either way I'd still run a 3K OCI with MMO to clean up the lower end, and the ring packs. Just keep an eye on the oil level. Change the PCV valve with an OEM valve if you haven't done so.
 
Thanks for all the good advice, everyone.

Whenever I pull the valve covers I'll be sure to post pictures (it may be a while).

Originally Posted By: lexus114
The rear valve cover will tell a lot more of the story,because that is where the pcv is located.


Yeah... I just wish the rear valve cover wasn't so hard to get to!
 
Originally Posted By: hypervish

My 1MZ-FE doesn't consume any measurable amount of oil in 7500 miles highway. I drive 100 miles a day, all highway. And take a >1300 mile road trip every 2 months.


The previous owner drove my car about 6000 miles a year, presumably only on short trips around town... with oil changes about once a year (the manual calls for a 5000-7500 mile OCI) for ten years. She probably never spent enough time on the highway to notice that it uses oil!

At least I got a good deal on it
smile.gif
 
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