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Discussion Starter #1
So our 2001 HL LTD V6 is consuming oil at an alarming rate. Qt every 300 miles or so. I believe it's doe to clogged oil baffles especially on the rear valve cover. I have come to this because when I pull the PCV out it is loaded with oil and you can see oil weeping all around the grommet and down in the opening there is oil. The previous owner led me to believe he only used Mobil 1 on the car but then later on when I was speaking to him about something else he said "nah I never use that crap just whatever they put in at where ever the oil was changed and on sale" So I believe things are pretty sludged up in the valve covers.

I have a friend lined up to pull them and his shop has a commercial parts cleaner. My question is this: Has anyone simply pulled the covers and had good luck cleaning them very well to stop the consumption? Or is my only recourse to get different cover(s)? Along with that do I need both? Or just the rear? The car is in nearly pristine condition and drives/looks nearly new (even though it has 185K on the clock).

I just invested in new t/belt, all new oil seals, tensioner/idlers, water pump, coolant flush, and new drive belts. The car does not leak a drop.

So thoughts/opinions? If I do NEED to replace the cover(s) what exactly do I get so my friend can install them for me. (the skill is there for me but the old body is weak don't relish being bent over that engine) so I will pay my friend who is a pro
 

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Well, if your engine does not leak out, it leaks in then. Catastrophically, I must say. Unless you missed zero in 300 number.

Go to tailpipe and stick finger inside. Is it all sooty?

You likely have blow by burn out. Stuck piston rings, hardened valve stem seals. The usual. Cure is either to pull heads off and replace seals and pull pistons same time, clean or replace rings. It's major overhaul whichever way you look at it.
That you have passages plugged in the head that's for sure, judging how much oil collects under valve covers.
Personally, I'd have done aggressive engine Seafoaming. 2 cans of Seafoam into crankcase, drive for about 500 miles, drain oil, do filter, refill, 2 more cans, do same, 2 more cans, do normal oil change. It's a bit of work to do but it will open at least most of the passages and remove at least some of the crud on piston rings. If you feel brave, you can pour Seafoam into cylinders and let it sit there overnight. Then start engine. Done it. It works fine, engine tends to cough a bit starting but worse part is - it will produce huge white cloud coming out of tailpipe for about 5 minutes. As in - solid military grade smoke wall. So hood may not appreciate this.
 

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If you feel brave, you can pour Seafoam into cylinders and let it sit there overnight. Then start engine. Done it. It works fine, engine tends to cough a bit starting but worse part is - it will produce huge white cloud coming out of tailpipe for about 5 minutes. As in - solid military grade smoke wall. So hood may not appreciate this.
Boy, does THAT bring back memories. Ukrkoz speaks truth here.

This is a puzzle to me -- how could this amount of oil consumption occur without destroying the a/f (oxygen) sensors and the cats... and triggering multiple OBDII error codes?
 

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Discussion Starter #4
I honestly do NOT believe it's any more catastrophic than sludged up valve covers. My friend can do the job for $400 and given the amount of $$$ I have invested in it up to this point the $400 is worth it IMO if it brings the consumption down to livable levels. I am 100% positive 80% or more is going in the PCV hose as oil stays up in the baffles when I put oil in or look at the PCV area. Just wondering if anyone has tried just cleaning the VC baffles or actually ended up replacing them and if so with what?
 

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When I replaced my valve covers, I took the old baffles apart and they weren't dirty inside. Point is... I do not think that just cleaning out the original baffles will fix the consumption. You need the new design. The problem with the original design is not simply a little crud inside the baffling.

I DO believe, however, that you could probably get away with just replacing the rear valve cover and leaving the original front one in place. But since the rear one is the difficult one and the front is so easy, you may as well just do both. The additional cost for the front should be well less than half the total labor.

Lastly, be aware... With 185K miles already on the clock, the internal damage may have already been done. I would run a compression test before you bother with the valve covers. Just do the front (easy to reach) bank. The desired result is 210psi.
 

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I used these:

rear (right) - 11201-0A060
front (left) - 11202-0A051

They were used on 2005 and newer engines and have superseded all previous valve cover versions.


A compression test on the front bank is easy-peasy and will tell you a lot. For reasons I've discussed here before, the number 2 cylinder is usually the first to go.
 

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some other posts on here have said that to re use the old valve cover, you need to drill the rivets out and remove the baffles to clean out the caked on gunk. In their opinion the deposits were too hard to get out with chemicals and needed to be manually scraped off. Then you would have to drill and tap the valve cover and bolt the baffles back on with some loc tite. Or get the newer style valve cover for a quick swap.
I think I have the same problem, but much less severe at a quart every 3000 miles. When I had the intake off it had a noticeable amount of oil in it, as well as in the pcv and hose connecting the two. If I ever need to have that manifold off again I plan on cleaning out my baffles. My hl has 260,000 miles and I've run mobile one and the larger TG 3600 oil filter since I got it at 76,000 miles, with oil changes every 6 to 7k miles. Everything was shiny clean under the valve covers at 214,000 when I had them off to get a wrench on the cams to get the backing plate off that covers the water pump, wish I knew about those baffles then!
 

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Discussion Starter #10
And here is another curious thing. IN an effort to "improve" the issue I put a new PCV in it. Well it changed but for worse. My consumption which had been about a qt every 900 shot up to a qt every 300! Frankly I don't consider a qt at 3k "consumption" I would consider that normal.

I am going to see if I can get valve cover(s) used from FleaBay. Will only Highlander covers work or any 3.3 2005 and up work?
 

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PN fits 3.0/3.3 pretty much all years/models

So, I would definitely gamble on a <$100 used fleaby/salvage yard cover. Just make sure its the 2005 or newer as some sellers are listing old ones for the entire year range.
 

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I didn't make this pic showing the difference, but I believe this is an easy way to tell the old from the new. Because of the changes in the internal PCV baffling, the old rear valve cover has two notches visible from the outside, while the new version has four.

Also, if you get good pics of the underside, the part number is cast into the material. 11211-0A060
 

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Discussion Starter #15
Those valve covers are as scarce as hen's teeth. I can find the front ones all day but this must be a huge issue for this engine as I can't find rear VC at all. Though did find one for sale but from a 2004 3.3 and it looked the same as what I have on the engine now. Just did an oil change on it last week and in 200 miles used up 1/2 qt.

Have a new OEM PCV valve on order at dealer as well. Hoping a new PCV brings it down to more livable levels. I ordered a generic one from Amazon to replace the one that's been in there since new but the generic is nothing like the old one and I may be mistaken but I think consumption went WAY up with it
 

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Well as a last resort, there's always new from the dealer. Quick look on-line says it's $250.

Changing the PCV isn't going to fix it. The problem is internal.

There was another Highlander owner here on the forum who reversed the direction of the PCV system. Instead of pulling form the right (rear) valve cover, he was pulling PCV air from the front one instead. Couple criss-crossed hoses and stuff. Seemed to work for him. Search around on the forum for that and see what you think. Might be able to at least buy you some time while you wait for the correct valve cover to pop up on ebay for cheap.

And whatever you do, don't wait too long. All that oil is being burned and is caking up your exhaust valves. Sooner or later, it's going to cause a more significant problem than having to put oil in frequently.

Speaking of such things... Did you ever run that compression test?
 

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Discussion Starter #17
Compoosh was fine on front 3 so I will assume/hope back 3 are fine as well. Engine runs like a Rolex. Quiet, smooth, good power and fuel economy. I have to assume nothing major is wrong internally. I may look into the pulling PCV from front. Another might be to put a catch can on the PCV as well. At least the oil won't get into the engine. Local dealer quoted me $350 for VC BTW
 

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Discussion Starter #18
Well I did the PCV reversal yesterday on the HL. I will monitor consumption (or hopefully lack of). Some observations. First I can see why the PCV is prone to sucking oil in. I never realized it but the engine has a slight rearward bias (rear of the car) putting the rear (right) valve cover lower than the front. The "vent" on the front cover is decidedly higher and taller than the rear one. Allowing oil in liquid form to be kept away. So bottom line if this stops/controls the issue to livable levels all is good and I may even splurge on a new valve cover and do the whole thing as "stock" again. If not than I will give up on the car.
 

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Mostly I think engine flush is snake oil. But I think you might be a candidate. The nice thing is it can't really hurt, your engine is probably FUBAR. The dealer can usually do a flush, or Oil Can Henry or even Jiffy Lube.

My mechanical experience goes back to 1969, fifty years, when oil really did sludge things up bad with parafin. Back in the days of Nixon, farmers would pour in a quart or two of kerosene or diesel, warm the engine up and let it sit. Softens up the wax, and makes it easier for marvel mystery oil to flush out. Pre-synthetic oil times. Motor oil was so worthless back then. My little sister gunked up the family loaner car with non-detergent oil, maybe 30 cents a quart in those days. It was thick, the valve train was covered in the crap.


I've heard that you can use ATF (amazing stuff.) As a cleaner, too. Less than a quart added, you can even drive the car for a day or two and not harm it.

I think I'd try a flush. And then ongoing treatment with MMO or Seafoam.:nerd:
 

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Discussion Starter #20
Brian, I seriously doubt an engine that runs so smoothly and quietly, with good compression and excellent fuel economy is "FUBAR".

Yes a "flush" MAY help a little but I believed and still do it's consumption issue is/was due to a faulty PCV system, Poorly designed and not able to take some of the buildup from non synthetic oil use and or not frequent enough oil changes for the oil type used.

As for ATF in place of or in use with engine oil that is a bunch of BS. ATF has high detergency but for completely different operating conditions. NOT inside an engine.

So far the PCV reversal appears to be doing what is intended. Prior to doing it the PCV Valve would be full of oil when you pulled it out. Now it is staying clean and free of oil.

Anyway time will tell. And yes my experience goes back to the late 60's when I did my apprenticeship and then became a full Journeyman. Some guys did advocate the use of ATF as a cleaner (most did not).

Most recognized that if it belonged in an engine it would not be ATF and if engine oil belonged in an AT it would not be engine oil
 
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