Lexmex

You are burning A LOT of oil for the km you have gone. You're losing a liter every 500 miles or so. That's ridiculous.

Oil Saver I think has one as much as it can do. I'm not sure of the quality of the current oil you are using, but that just doesn't make sense in terms of consumption. I'd seriously put some different oil in there. 5W40 Liqui Moly is some serious oil, but a drawback there is your km/l will go down, that's what I found, but I can't justify losing a liter every 500 miles like that. What kind of oil are you using right now?

Nad1370

You mentioned all piston rings were replaced right?
How about the Oil Rings ?

I hoped they were replaced too since you had a sludge motor to begin with.

150 psi for compression? After a rebuilt?
Maybe it hasn't been fully broken in yet but 145psi is min. and 218psi is max.

Oil is def. getting burned in the combustion. Either coming through the piston rings or leaking past the valve seals.

I would do another compression test. If you still have a "low" reading, try to put 1/2 ounce of oil in the cyl. through the plug hole and re-test it. Do this in all cylinders.
If the reading is considerably higher, then you know where the problem lies.

aejaz

Thanks Lexmex and Nad1370

Lexmex, this oil burning issue is only when I got 500 miles on highway continously
No oil loss even for 5000 KM if its run in the city

The toyota oil is 20w40 (Or is it 20W50)

Nad1370
I am not sure if the oil rings are replaced.
Can you put more light on oil being burned in combustion .. (I am not good at automobiles terminology) or the compression test by putting some oil in cyl?

I will go for a compression test again, but I would like to carry some more information myself about it -

Thanks all again

Lexmex

Not sure if you are using 20W40 or 20W50, but top end I'd go would be about a 10W40. I've run 5W50 and even a 15W50 very early in the ownership of my RX300 (there were synthetic oil availability issues in the early part of the decade in Mexico).

What Nad1370 is talking about is that the oil itself can seep around the rings and get into the combustion where the air and fuel are mixed. He's advising a compression test (a dealer should be able to do this if they are competent) and see what the compression is in each of the 6 cylinders in the vehicle. Although I am aware you mentioned they did an overhaul on the engine, it's just really strange that you are still getting this issue.

Bad compression in one or more of the cylinders would allow oil to seep into the combustion. One possibility (and it should have been observable when they were working on your cylinders) is that the cylinder walls were pitted/scarred, but even then I find this absurd because a competent mechanic would have noticed this issue if it existed and it would have also affected your city driving, too.

I'd strongly suggest moving to a different grade of oil, say about a 5W40 or 10W40. One possibility that also comes to mind (but even then I'd be scratching my head) is that highway driving at higher speeds with that 20W oil (and that's not an oil that is going to flow as well as a 5W or 10W oil) is just sitting there and getting cooked because there is less flow. You'd probably see that same oil get cooked over a longer period of time if all you did was city driving. However, this would still likely occur over a longer period of time. The 20W40 or 20W50 is definitely well out of specification.

aejaz

Thanks Lexmex again

I wont say its overhaul, but just a headjob

I had vibration/misfire lately while idle as well as running, so went for a compression test (oil burning was since I got this vehicle 2 yrs ago), one of the cylinders has 0 output.

After the compression test, the mechanic opened the head to see what is wrong at the cyl where there is total compression loss

Found a burnt valve, he suggested replacing valves and then suggested maybe a good idea to replace the piston rings as well to see if it can solve the oil burning
A lot of things were replaced including spark plugs and fuel pump, piston rings.

I asked the mechanic if it needs some work on cylenders and pistons
He said the cyls and pistons are ok, he even explained what is a bad cylender means, by showing the clean surface of the cyls with no scratches/scars etc

After all the above the oil burning has become less but not totally gone
Was it sludge ? And there is some more remaining underneath somewhere or is it burning at the combustion level like NAd said..

To overrule the sludge further I tried the Liqui moli flush and oil save .. No Sludge remover available here..


I have earlier tried with the Synthatic oil before the Engine head job, with the same results


I have always changed oil after the oil burning in highway, then continued in the city, no burning of a single drop even after 4000 KM with Toyota oil ( 20w40 ?)

I will go for a compression test.. and If it gives me 150 PSI on all cyls.. what next?

I had earlier decided to ignore the oil burning as My highway long trips are very few (Once in a few (2/3) months .

However Now I am afraid that can it again burn some valves and or bring me some more engine issues further?

Otherwise I am ok to live with the burning oil thing as I know this devil, I will fill it when it needs the oil -

Yet I am curios to find a fix .. At this point I am reluctant to open the engine to a cyl job or piston job , Opening engine is to spend a minimum of $1500 to start with ..

Not sure if I have to try the heavier or synthetic oil again now

Lexmex

Problem is if you have something like a 20W oil that stuff is not flowing, it's literally sitting and can't cool as well. The 1MZFE engine has narrower oil passages than its successors in the 2nd and 3rd generation RXs.

aejaz

Hmm then I think I should go for a heavier oil and try
5w40 or 0w40? Liqui Moly or any other one .. Any suggestions?
Looking the description of these oils, it doesnt look like it needs an additive as well..

Do you agree

Any fuel additives?

Lexmex

The problem is not the W40 or W50, it's the number in front of the W that I'm concerned about.

This is the list I'd consider in your situation:

Castrol Syntec 0W30 (that might be found at BMW as an LL-01 oil with a 0W30 on it). (this is what I use right now).
Castrol Syntec 5W40
Liqui Moly 5W30 (that's probably the heaviest 30 I know of)
Pennzoil Synthetic 5W30 (it's called Platinum in some places)

You don't need any more fuel additives for the time being.

aejaz

Got the Liqui Moly 3w40 last week (7 days ago)

Today I noticed some drops of oil (More than the earlier one which was stopped after using the liqui moly oil saver ).

Can this be due a heavy oil ?
Is it a bad filter ?
Or Should I have used the Oil saver again with the new oil change?

last time I used 4.5 + 300ml (is it 300 or 550) of OIL saver which seemed to have stopped the little leak that was seen earlier

This time I have filled 5L, this time like everytime
The workshop guy who changes oil says, when the filter is changed the oil has to be 5L, otherwise 4.5L is enough


What else it could be?
Any suggestions are highly appreciated

Lexmex

Actually, 4.7L with the filter changed out, 4.5L if not. I always change out the filter when changing the oil, though I have experimented maybe 7 or 8 years ago with not doing one just to see and the vehicle never feels quite right unless the filter is changed out.

I did an oil change here, https://www.clublexus.com/forums/rx-...il-change.html

If you put in 5 quarts (or 5 bottles of oil) you'll get 4.73 liters at the end, which is close enough.

That Liqui Moly 5W40 is heavy. I've used that before in Mexico so I know exactly what the feels like.

Let me show you something so maybe we can solve this problem once and for all, because I think you are moving in the right step with the oil.

A possibility of where you might have an issue is something called the rear main seal shown in the first picture (blue circle). That seal is located behind that round disc you see in the second photo and it would leak right to the left of the silver area you see in the middle of the next photo right by or on to the exhaust. If it leaks there, they have to separate the tranny from the motor and replace the seal. That's one possibility.

Another possibility is leaking anywhere where the valve cover seal is as shown in the fourth photo where the blue line is. That gasket can leak.

The only other thing that's occurring is the oil is still burning past the piston rings and into the combustion. I've known that even after some one goes in there and fixes these things.

The only other place you can look is around the oil pan itself and its gasket and that's the fifth photo.

There's not really any other place I know of. Even where the oil filter is located is pretty tight and I don't think you'd seen an issue there either.


and it would leak in the second photo below.

aejaz

I am sorry the the OIL I am using is 5w30.( I guess the 40 or 30 dont make much difference).

I should go to the mechanic to verify the above things..

Lets see.. or can it be due to little more oil added than required quantity?

I too always change the filter when oil changed..

Guess now the oil saver cant play much role -

Lexmex

Depends on the oil brand and weight. The Castrol 0W30 I use is more like 0W40, but the 5W30 from Liqui Moly is like 5W40. It just depends.

I've run more oil than required numerous time throughout the time I've owned my RX300 and never have seen a leak. A little over won't kill it and that's before I was running the oversized HP-2009 oil filter from K&N. The original size is HP-1002. You may like running the bigger oil filter (and I showed it in that DIY link I did above).

http://www.knfilters.com/search/dealersearch.aspx (do a search under Saudi Arabia as there are three dealers listed, one of which is in Riyadh).

aejaz

Today afternoon (Afternoon in Riyadh)) I noticed , as soon I started up, before switching any gear, there was oil not just in drops but kind of little drain for few seconds.. i am sure it drained/fell atleast 50Ml and stopped.. then dint leak until now.. I stopped again now.. will have to start again after in 3 hours.. will see if this happens again

This happened for the first time anyway

About Synthetic/heavy OIL

Was going through the autrx application instructions

AutoRX for some reasons seems to suggest conventional oil and discourage the synthetic or heavy oils..

In the instructions to apply the AutoRX for a oil leak stop, it says to use the conventional oil only and even says if returned to Synthetic or any heavy oils the OIl leak could return back.. Any comments?

Lexmex

You may want to have someone else start it up and see if you can see where the leak is coming from.

Yes, AutoRX should be used with conventional oil. Chevron is a very good one. Let me know what conventional oils you have there and I'll suggest which one. Shell would also be a good conventional oil to use if you have it there. You only need to use the conventional oil while running the AutoRx.

aejaz

I started and could see it myself when it leaked in the afternoon, it went for few seconds
the oil flow in the afternoon was from the center , somewhat similar to what you showed the leak at the main seal..


But this dint happen again ,,

There is no leak now when I start it up, only after stopping there are a few drops here and there but at three different places.. sounds like the remains of earlier one and dripping from the pan..

The dip stick level was 2-3 mm higher than the normal, but now its to the normal level after the large amount drained in the afternoon today..

Can it be due to heavier oil..

I wish I could go to a mechanic and verify today.. Cant go until Saturday due to weekend planned activities