I have a 2000 1MZ-FE engine with 306k miles.

I know these are sludge engines and I run synthetic oil and change it frequently.

The vehicle burns alot of oil, I am trying to narrow down how much but I believe it is in the ballpark of 1 quart every 500 miles.

I notice if the car sits for a couple of days it smokes alot at startup. I guess this is a sign of worn valve guides?

My main question here is what failure will the oil burning eventually cause? (Assuming that I don't run the engine low on oil)

Will the O2 sensors fail? Cat Converters? Other? Just wondering what I should look out for or be ready for?

Thanks

Plenty of discussion on this topic. One possible source you did not mention is the PCV to air intake. You can devise a catch can to check. You can run compression test too

Salim

I would try replacing the PCV valve in case it's stuck open and sucking oil out of your valve cover and into your intake manifold.

Also, is the engine leaking oil?
If so where?

Edit- it looks like me and Salim were posting at same time, 2 votes so far for checking the PCV valve. lol

I'll look into the PCV, but I think the valve seals are leaking.

1+ for the catch can. I used one to confirm how bad my PCV valve was before changing it. I liked the idea of it so I made it a permanent addition to my old Highlander with the 1MZ.

It was so bad that my car would smoke like crazy and the can would fill up every 500 km! Was also going through oil like crazy as well. Changed it 4 months ago and haven’t burned a drop of oil since.

thanks for the info, I have a few followup questions.

1. Do you have a catch can recommendation, Amazon or other?
2. What did you mount or screw the catch can into?
3. What do you mean by " Changed it 4 months ago". Changed what? Installed the catch can?
4. What do you do with the oil in the can? Dispose of it or pour it back into the engine?

Thanks again!

If you have a known leak then that should be addressed. Although you can make educated guess regarding the volume of oil being lost overtime. There maybe more than one source of leak.

Catch can is not a solution ... it is just a simple in line device to collect liquid and let the vapors make their way to the intake. This just confirms if you are sucking in oil through the intake.

At the end (after diagnosis ... catch can, visual leak, compression test etc) the question is going to be what do you plan to do. Repair each or take care of the minimum. At a certain stage you may choose to live with it ... put a cardboard underneath, keep an eye on the oil level.


Salim

1. I just got the standard cheap 30 dollar one from Amazon, didn’t want to go spend 100 bucks on a simple can and this works just fine. Maybe if our cars had direct injection I’d grab a fancy one.

2. Not sure if the 1st gen RX is the same, but there was an existing hole drilled into the strut tower bar for an M6 x 1.25 bolt on my Highlander. I used a satellite dish mounting bracket to fasten the can to that.

3. Changed the PCV valve four months ago and that confirmed the bad valve, the can has been on for five.

4. I just store the oil with my other used oil containers. You definitely don’t want to be pouring that contaminated oil and condensation back into your engine.

If the PCV Valve is bad you can definately see that kind of massive oil loss you are describing.
Only a few dollars to find out and hoping success for you.

Nonetheless, you need to find the oil leak fast before you accidently run the engine low on oil and then it's game over...
PS- valve guides can be worn sure why not, but a few cans of spray brake cleaner on a cold engine will degrease it well and can find source of oil leaks if you have any. Use with care and don't squirt anything painted that will be seen or electrical including the alternator- just the metal parts and suspension if you car is an oil leaking pig. lol

On one RX300 of mine, a switch from Mobil 1 to Pennzoil Platinum completely solved the massive oil consumption problem. It didn't solve the problem on my other one, but replacing the rear valve over with the newer style (along with the different style PCV valve) solved it. Great advice in the preceding posts, too!

Looks cool, are you going to leave it on there?