Valvetrain sludge: 2007 Toyota 4Runner

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I picked up an '07 4Runner with 163K miles, 4.0L V6 as a project...chronic P0016 variable valve timing error, bank A. Pulled the passenger side valve cover to verify timing and found a minor sludge-fest as shown in the pics below. Maintenance records are very sparse on CarFax and Toyota, the original owner said he had a local shop do the oil changes at 5K mile intervals, unknown oil brand. The P0016 code is gone after removing and cleaning the intake cam (sludge accumulation in the VVT oil passages) and replacing the big VVT actuator on the front of the intake cam. I'm running Rotella T6 0W-40 and a Toyota filter. Will be back under the valve cover soon to replace the [censored] aftermarket #2 timing chain tensioner, the nylon pad is being touched by the #1 chain at idle causing a clicking sound.

Sludge pics below, feedback is appreciated:


 
A lot of heavy varnish there. Did you clean out any sludge? If not, it's actually not all that bad looking from the pics and considering the 163k miles on the engine. Also we could assume cheaper oil was used.

Do you plan to run some short OCI's to work on that varnish?
 
Looks like you caught it in time...with some TLC it should be good to go. The 4.0 is a good engine generally.

I don't think the previous owner was entirely truthful about the oil change regimen....
 
Four or five cans of Berryman B-12 Chemtool to hose down the valve train area followed by an immediate OC and some short OCIs thereafter will have it looking like new.
 
Not awful, seen much worse. Some heavy varnish, light-ish sludge areas. Also doubting history of regular 5k oil changes even with bulk API rated conventional.

Perhaps some shorter ocis using synthetic and gradual clean up. No drastic measures needed IMO.
 
Thanks for the feedback. I cleaned the valve cover w/ B12 and a nylon brush, good high pressure airgun blast after it dried. Inside, I only cleaned the intake cam, bearing caps, and bolts. Found solid sludge in the cam oil passages that supply pressurized oil to the VVT actuator and scrubbed them out gently w/ small nylon brush from Harbor Freight (airgun cleaning brush set $1.99).

I'm letting the T6 0W-40 do what it can to gently clean the remaining sludge. It'll have approx 500 miles on it when I open it back up this weekend to replace the #2 timing chain tensioner again, will snap pics for comparison but I'm not expecting to see much improvement as yet.

My theory on the P0016 error was either sludge blocking the pressurized oil feeds to the VVT actuator, or the actuator itself clogged/jammed with sludge. I had already replaced the VVT solenoid and cleaned the VVT oil filter screen prior to opening up the valve cover, neither move had corrected the error. It's a fun project thus far.
 
Good on you for cleaning up/fixing up this vehicle that will last another 10 years.
That isn't nearly as bad I was expecting. I would change the filter at 500 and let the oil run another 500, and then put whatever is spec'd, full syn. It will be just fine.
 
The really interesting thing is the sludge buildup on the #3 bearing caps. Little to no sludge on the #1 and #5 caps...the close-up shot is the #3 cap on the exhaust cam. Seems like there may be more heat or less oil spray there.
 
Looks like oil condensation from short trips. assuming that the pcv and hose are clean and working properly.
 
Originally Posted By: JTK
Cool pics! Doesn't look bad to me at all given the age and mileage.

Gee whiz I think it looks awful for that mileage. My ancient Sienna with nearly 400K miles doesn't look anything like that.

I have a very hard time believing there were consistent 5K oil changes on that engine regardless of what oil was used.
 
Make sure the headgasket is still good on this motor. The older 4.0s would sometimes develop headgasket leaks and that could be responsible for your sludge.
 
I agree with the two statements above. It doesn't look all that great. However, a project is a work in progress!
 
Originally Posted By: crainholio
The really interesting thing is the sludge buildup on the #3 bearing caps. Little to no sludge on the #1 and #5 caps...the close-up shot is the #3 cap on the exhaust cam. Seems like there may be more heat or less oil spray there.


I was looking at the same thing. Might be worth a look underneath to see if you have any galling under there.
 
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Looks terrible to me. This is likely the results of dino with extended OCIs. The last time I had an engine look like that was in the 60's using QS.
 
Originally Posted By: crainholio
Maintenance records are very sparse on CarFax and Toyota, the original owner said he had a local shop do the oil changes at 5K mile intervals, unknown oil brand.

Let me translate this for you.
"I was talking with my buddy after 6-8 beers during the Superbowl. He said he had his oil changed one time at a local shop, but can't remember what shop, what oil, and I think it had 5,000 miles on it. That's what I'll tell the buyer of my 4Runner"
wink.gif
 
I had the same truck and V6 in a 2006 that I put 200,000 trouble free miles on it was solid when I sold it. I replaced a valve cover gasket at 150/160k (did both) and my motor was spotless with 5,000 mile OCI running either Formula Shell synthetic or Wall Mart ST in either 5 or 10w30 never had to add a drop of oil between changes. I tried running Shell RTS 5w40 once and it made the truck run slow like it was driving threw "taffy" so I stuck with the 30 weights.

How is the frame rust? Mine was starting to get bad but that is typical for Western Massachusetts with the brine mixture they use on the roads here it is 12 times more corrosive then rock salt! ... Really [censored] me off!
 
Originally Posted By: Camprunner
I had the same truck and V6 in a 2006 that I put 200,000 trouble free miles on it was solid when I sold it. I replaced a valve cover gasket at 150/160k (did both) and my motor was spotless with 5,000 mile OCI running either Formula Shell synthetic or Wall Mart ST in either 5 or 10w30 never had to add a drop of oil between changes. I tried running Shell RTS 5w40 once and it made the truck run slow like it was driving threw "taffy" so I stuck with the 30 weights.

How is the frame rust? Mine was starting to get bad but that is typical for Western Massachusetts with the brine mixture they use on the roads here it is 12 times more corrosive then rock salt! ... Really [censored] me off!


I had a 1990 Ford Tempo and used M1 5-30. I tried one change to M1 15-50 and the engine felt noticeably sluggish. Changed back to 5-30 and all was well.
 
Originally Posted By: kschachn
Originally Posted By: JTK
Cool pics! Doesn't look bad to me at all given the age and mileage.

Gee whiz I think it looks awful for that mileage. My ancient Sienna with nearly 400K miles doesn't look anything like that.

I have a very hard time believing there were consistent 5K oil changes on that engine regardless of what oil was used.



Probably not consistent oil changes, but I would hardly call this engine badly sludged up. In the 70s and 80s, I saw running engines so sludged up, the gunk took the shape of the cam/valve cover. I've seen oil pans not drain until you poked a screw driver through the drain hole. They were probably half this age and mileage as well. Times have changed obviously.
 
Originally Posted By: JTK
Probably not consistent oil changes, but I would hardly call this engine badly sludged up. In the 70s and 80s, I saw running engines so sludged up, the gunk took the shape of the cam/valve cover. I've seen oil pans not drain until you poked a screw driver through the drain hole. They were probably half this age and mileage as well. Times have changed obviously.

No, not badly sludged up. I just didn't think it looked good at all especially compared to my engine with over twice the mileage.

I've only seen one badly sludged engine. That was a friend's Sienna where they severely short-tripped the engine in cold conditions, and the owner told me he was "pretty sure" they got the oil changed a couple of times a year. Fortunately for them they were covered under the Toyota repair program for those engines, but that (to me at least) was a clear case of user error.
 
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