Valve Cover Off (Toyota 2AZFE)

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I replaced my wife's 2004 Toyota Highlander's valve cover gasket today. Overall, things look pretty good. No sludge. However, I noticed the back camshaft is darker than the front camshaft. Any idea why? I've been running PU 5w-30 for the past 20k miles. Car has 125k miles on it and it is burning 1qt of oil every 3.5k miles (typical 2AZFE engine). Inputs are welcome! -ttvr4
 
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Wonder if the engine had some sludge before the PU cleaned things up a bit. There are some signs of varnish that was / is being cleaned up. What was the OCI and prior maintenance history?
 

ttvr4

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Originally Posted By: 147_Grain
Wonder if the engine had some sludge before the PU cleaned things up a bit. There are some signs of varnish that was / is being cleaned up. What was the OCI and prior maintenance history?
Current OCI is 8k. No idea what the previous OCI was but I know that cheap conventional oil was used before we inherited the vehicle. -ttvr4
 
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Looks like it was eating conventional before you got a hold of it and the PU cleaned up one side better than the other.
 
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Must be more blow by gases pass around the intake cam portion of the head. Is the underside of the valve cover also darker on that side?
 
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I believe the intake rear cam darkness with some crud buildup is possibly due to driving short trips and not letting the engine get hot. The exhaust side runs hotter normally and thus the cam is clean.
 

Leo

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A slight tinge of varnish but nothing harmful, especially for the miles. Not sure how to explain the crusty deposits on the VVT actuator though but it certainly isn't detrimental.
 
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Know the engine well. Written about this engine and its problems recently on here. The dark one is the vvt-i cam gear. Prone to deposits with the wrong oil which is a bad thing. The picture shows the cover of the gear picking up oil/blowby vapors (close to PCV valve outlet), not much flow over it so it doesn't clean easy, some cooked oil from high heat, similar to what you see on the valve cover baffle. Its whats going on inside the gear that matters. The deposit problems with this engine are block level, deeper inside at the pistons. Peeping under valve cover doesn't tell you much about the cleanliness below. Its either burnt/worn valve seals or clogged piston oil return holes causing the consumption. Assume you switched over to PU from another oil for a reason. What was the prior oil brand used? That will help diagnose where the oil consumption problem lies.
 
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Here are a few pix of my 2az-fe engine with VC off for you to c/c... ...it had 97.5k miles with Shell conventional OCs done 1x/yr @ 10k OCI (if you believe Carfax) or 5k-2x/yr if you believe the owner..then 3k with PYB conventional...when it was changed @ 103k to PP syn...all 5w-30... Note.... ...the pic under the fill hole (looking at the baffle and the camshaft under it) was about 1k into that 1st OC with PYB where the cam shaft was darker than 2k later with the VC off. ...the underside of the VC shows blow-by from older plugs that needed replacing even though I was getting great MPG (24.5 city-34.5 @ 70-77mph) and a PCV valve that had been cleaned @ 100k knowing it would be replaced at the next OC, 2k later....when the plugs would be replaced with a new VC gasket...it was brittlecardboardhard... ...the PCV hose that was brittle-hard cracked at each end... note that the darker areas on the camshaft are lighter here than when viewed under the fill hole 2k earlier... My engine is burning 1/2 qt/3k miles with PP, a bit more than it did with PYB...I think it burns more on the highway but have too little experience with too many other factors to say that definitely...nearly all my mileage is around town.
 
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I think the PU 5W-30 is still cleaning it up, but it still looks great for 125K. Keep doing what you're doing and top off the oil whenever half a Qt low. I bet the consumption might decrease in time.
 

ttvr4

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Originally Posted By: LeakySeals
Know the engine well. Written about this engine and its problems recently on here. The dark one is the vvt-i cam gear. Prone to deposits with the wrong oil which is a bad thing. The picture shows the cover of the gear picking up oil/blowby vapors (close to PCV valve outlet), not much flow over it so it doesn't clean easy, some cooked oil from high heat, similar to what you see on the valve cover baffle. Its whats going on inside the gear that matters. The deposit problems with this engine are block level, deeper inside at the pistons. Peeping under valve cover doesn't tell you much about the cleanliness below. Its either burnt/worn valve seals or clogged piston oil return holes causing the consumption. Assume you switched over to PU from another oil for a reason. What was the prior oil brand used? That will help diagnose where the oil consumption problem lies.
I am not sure what conventional oil was used and its OCI prior to taking ownership of this vehicle. I'm more concerned about the car burning oil than anything else. Should I be switching over to a HM oil? -ttvr4
 
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Originally Posted By: ttvr4
I am not sure what conventional oil was used and its OCI prior to taking ownership of this vehicle. I'm more concerned about the car burning oil than anything else. Should I be switching over to a HM oil? -ttvr4
I have one and never go past 5000 miles with synthetic. At almost 80,000 miles I am using no oil in a 5000 OCI. I use mostly QSUD or PP 5w20.
 
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Originally Posted By: ttvr4
Originally Posted By: LeakySeals
Know the engine well. Written about this engine and its problems recently on here. The dark one is the vvt-i cam gear. Prone to deposits with the wrong oil which is a bad thing. The picture shows the cover of the gear picking up oil/blowby vapors (close to PCV valve outlet), not much flow over it so it doesn't clean easy, some cooked oil from high heat, similar to what you see on the valve cover baffle. Its whats going on inside the gear that matters. The deposit problems with this engine are block level, deeper inside at the pistons. Peeping under valve cover doesn't tell you much about the cleanliness below. Its either burnt/worn valve seals or clogged piston oil return holes causing the consumption. Assume you switched over to PU from another oil for a reason. What was the prior oil brand used? That will help diagnose where the oil consumption problem lies.
I am not sure what conventional oil was used and its OCI prior to taking ownership of this vehicle. I'm more concerned about the car burning oil than anything else. Should I be switching over to a HM oil? -ttvr4
Alright. No problem with the rings or cylinder bore on these engines. The oil consumption is heat related. Either the valve seals are dry/shrunk/burnt, or the piston oil return holes are clogged from prior dino that flashed off in the holes, or both are contributing. On the 2AZ-FE Camry in my sig I tried just about every additive, every oil trying to clean my way out of oil consumption. From regular M1, to PP and MMO, PU and Kreen, the list goes on and on. For me, on this engine Mobil 1 High Mileage 5w30 by itself is the choice. Its extended interval syn. Has seal conditioners to deal with valve seal issues. Has extra cleaners to deal with clogged piston oil return holes. Consumption diminished, external leaks stopped. Diminished is relative, I was 1qt per 2k, now its 1qt per 4500-5k. Not bias towards M1, like the PU better in the GM in my sig. Quieter. But the GP still has stubborn varnish on the dipstick PU cannot remove. M1 HM made short work of the varnished dipstick in the Camry, may try it on the GM. Also, a high efficiency filter is helpful to keep the holes clear of the smaller deposits, keep the oil looking cleaner for the 8-10k intervals I go with M1 HM. Something extended interval, 99% efficiency. I use the Fram Ultra XG4386 because its cheap at walmart where I buy the oil, but there are other options out there.
 
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Also, get a new Toyota OE PCV valve. Don't use aftermarket, they are noisy and for whatever reason suck more oil. And.. Your aware of the headbolt issue right? Change the coolant early and often. No substitute coolants. Maybe the pink, but its more expensive than the red.
 
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