1st gen sludge in the valve cover 130k miles

I searched and could not find anything to specific. I have a 2003 3.4l tacoma 4x4 5 speed. My grandfather sold it to me with a bible full of meticulous maintenance. I changed the oil for the first time since i had it and notice quite a bit of sludge built up. Its hard and gritty. I filled up with high mileage pennzoil and replaced filter. 1st question is how is there so much sludge with how he took car of his truck on top of the pretty low mileage? Is it a common problem on the 3.4l? 2nd question is how should i take care of this? I was thinking mabey some atf added to the oil and change every 1500 miles mabey until it clears up. Unless there is a better chemical or way to do so. I know you wouldn't want to clean all of it out at once and clogged the engine. Any help would be much appreciated, thank you.

 

Definitely don't add atf to the oil. That will destroy your catalytic converter.

I don't know how the sludge would build up unless it was driven short distances, as frequent oil changes really minimize sludge formation.

 

Hi mileage mix oil has cleaners in it,

There's a good chance the valve intake is filled with carbon too

 

Do a leak down test lots of sludge might mean worn valve seats getting lots of blow by.

If your Grandfather did the hands on work himself all well and good other wise you have no idea what was really done .

 

Where did you see sludge?

It's normal to see in the oil fill hole as that is baffled.

 

Im sure there is definitely a good amount on the valves, i doubt i can do much about that without pulling t

Just in the oil cap hole, i was thinking of pulling the valve cover just because i need to replace the gasket anyways to see what it really looks like in there. From what i can see its definitely the worst ive seen with any of my vehicles in the past.

 

this is usually a result of not getting the engine up to operating temp for an extended period of time to burn this off. The PCV valve handles these vapors. You could attempt to clean it up slowly but these "hard and gritty" bits dont just desolve. There is a possibility of them finding their way into the oil pan and either blocking the oil pickup screen or bypassing the oil filter and getting into the bearings.

 

You can clean the valve carbon if the plenum is removed when u do the valve covers

 

I agree 1000% try not to poke the hornets nest... you don’t want to loosen that stuff up. In fact, you are probably better off staying w/ whatever oil was being used prior...

 

Carbon filled intake section with the valves.
One with Carbon and a photo of mine

 

In the oil fill is just from vapors collecting, as i said it's baffled to keep from oil spraying out if you accidently open the cap while running.

Mine is black as night and carboned there also but under cover is clean, not 1997tacomav6 clean but just amber colored.

 

Hum, I have 414,000 miles on this one and the valve cover hasn't ever been off, wonder what it looks like underneath?

 

If you tell me how to post photos, I will show you some really bad sludge in my 2000 Tacoma 2.4L 2RZ-FE. It is having open heart surgery at the moment without pulling the engine. Having to buy a new timing chain cover because there are cracks in the area behind the water channel. and I have many stories to tell.

 

These 3 steps right here.
#1 - Upload file
#2 - Choose file
#3 - Choose from Photo library

 

Thank you for your really quick reply as to how to upload photos. Something just came up that needs my attention, and I have to get photos from my camera to the laptop and then upload them. Maybe tomorrow I will have the time. But you will see that sludge is not a pleasant sight inside an engine.

 

First attempt at posting sludge pictures of my 2000 Tacoma 2.4L 2RZ-FE engine (2WD and 5 speed MT)

Ok, let me begin my story. Several months ago now, my Tacoma pickup had been leaking oil for quite some time. I had pushed off the work of fixing the leak, thinking when I first tried to locate the leak that it was probably the rear main seal, which would take me a little "getting into the proper mood" to do that work. What actually stirred me into action was the day that I saw billowing oil smoke rising from the hood. After opening the hood, I could see that oil was coming out from the valve cover gasket at the rear right (passenger's side) and the oil was dripping onto the exhaust manifold which was burning it and turning it into a cloud of oil smoke. My alarm was a fear that the oil might start a fire in the engine compartment, since it was coming out at such a rate.

So, asap, I removed the valve cover, and as I did, I saw that the camshaft level of the cylinder head was full of gross thick crispy oil sludge the likes of which I had never before seen. I took some pictures because it was so bad looking, and I had the truck running prior to stopping to check the oil smoke, and figured there must be a way to deal with the sludge without tossing the engine into the scrap heap. Hopefully, I can introduce those pictures at this point.



Well, that's the underside of the valve cover, showing that the sludge was clearly very bad. Then I took a closeup of the end of this side of the valve cover to show the condition of the gasket. It was obviously beyond end of life, as it was cracked in several places. Here is the side where the oil was pouring out of the valve cover.


I think that is bad enough, but take a look at what I saw in the top of the cylinder head. This looked incredible to me, having never seen engine sludge. Didn't look like I would have a chance to fix my engine at that point in time. Here, you take a look and see if you don't agree.



It looks like there is more sludge the closer you get to the firewall. What this picture doesn't show is the condition of the oil channel that runs the length of the centerline of the camshafts. The exhaust cam oil channel was completely blocked. It isn't blocked any longer, but when I first took the camshaft out, it certainly was blocked. However, I must be extremely lucky because the bearings and journals of both camshafts were not ruined. In fact, after I did a small bit of polishing, they seemed almost perfect.

Of course I had to take out all of the valve train components (shims, lifter buckets, retainers, keepers, springs, valve stem oil seals) so that I could clean everything as well as I could and let me put new valve stem oil seals in for the 23 year old seals. Putting all those components back together was not "a piece of cake" like for some Toyota engines. I had the removal tool because I had to rebuild my 1994 Celica some years ago after overheating the engine. But that same tool was not exactly correct for use of the 2RZ-FE engine. I used sandpaper to grind the tool diameter at the working end enough that it would go into the bores for each valve train. But I did get it to work. And I was able to purchase the proper tools for changing shims when checking valve clearances, so that all went fairly well, IMO. I will come back later and post the photos that show the AFTER cleaning results. This effort is to document the condition as I tore into the engine.

Once the valve cover and the cylinder head had been cleaned as best as I could, I put the valve cover back on with a new gasket and moved down to see if I could remove the oil pan and clean whatever I might be able to of the bottom of the engine. Here is the way the inside of the oil pan looked when it first dropped away from the block:



It looked pretty ugly, I admit, but maybe it could have been worse? Whatever, when I took off the oil tube and examined the oil strainer, that's when I got to feeling a little sick to my stomach. Oil flow through that strainer was almost completely blocked with sludge sediment!! I then really began to worry about how much damage had been done to the engine inner parts due to lack of good oil flow. I still don't know the answer to that, but soon will.

Here is the oil strainer condition prior to cleaning:



And here is the oil pan just prior to cleaning it:



The underside of the engine was bad, but not so bad that I felt sicker:



I cleaned all that oil sludge as best as I could, and got it looking fairly good (Photo later). Then I took off one of the rod caps and examined its bearing. Looked ok to me. Gave me a little confidence that I might have caught this problem BEFORE the engine was a disaster. Have to wait and see.

After gaining a little confidence from cleaning the belly of the beast, I turned my attention to the timing chain cover. Here is where I took a short cut from the procedure described in the FSM. I did NOT remove the head, and that short cut almost caused me to destroy the timing chain cover while prying it off. You see, when removing the head, you have to remove all of the head bolts. That means that the two head bolts in the very front go through the "head" and screw into the timing chain cover. Since it was the first time I had removed this particular timing chain cover, and partially due to the fact that the engine was covered in oil and dirt and whatnot, it wasn't clear to me how I was supposed to get it off. The FSM said I should use a plastic hammer to remove it. Well, with those two bolts tightly holding the upper part of the cover, there was no way that I was going to pry it off without breaking some metal. I used a dozen razor blades around one side of the cover, tapping them gently into the interface between the block and the cover, getting as many as three stacked together, causing the seam to get enough wide that I was able to try one of my plastic body part removal tools into the crack and tried to use a hammer to cause the cover to separate from the block.

Luckily, when it seemed to me that all my work should have broken the cover free, I began to search around on the internet. Luckier, I landed on a site called "JustAnswer" which has some Toyota techs answering questions for money. I didn't have to ask any questions of them because there was a posted interaction with an earlier customer who was talking about exactly my problem, and mentioned the fact that they had used the same shortcut of not first removing the head. That got my interest up to a very high level, so I slowed it down and carefully read that text over again. It talked about removing the valve cover to get at two bolts that had to be removed in order to remove the timing chain cover. I quickly went back to the FSM, and after a few minutes of squinting my eyes, there it was, the two bolts, and the bulges in the timing chain cover where the bolts get screwed into the top of the TCC. Despite having just recently put everything back up top, I ripped it all back off and took off the valve cover and there they were, in that forward most areas where the chain comes back up and goes around the intake cam sprocket!!!!!

To me, that was high drama!



Once the cover was off, I took off all the timing components and began cleaning what I could. Here is a photo of what I found behind the timing chain cover:



All's well that ends well, right?

Well, the end is in sight, but I am not there yet. It is a tedious process, cleaning the sludge out of an engine, and I won't really how well I have done until I get to the very end, when I do a chemical wash of the internals and get the remaining oii sludge out of it, but that will be a while. I have to locate a fair number of parts that I want to replace in case the engine hasn't been destroyed. And it isn't so hard to destroy the metal parts of an engine. For example, take the timing chain cover, I now plan no replacing it because it has developed some "fractures" of the aluminum metal, probably over the 23 years of service this truck has given up. They are mostly hairline fractures, and almost all of them are related to the water channel. One crack, in particular, is so deep and obvious that I cannot just put this old cover back on and hope for the best, and I didn't want to try to find a good aluminum welder to fix it the ugly way. Here are photos that show you what I am talking about. First is the backside of the cover as clean as it needed to be in order to see the fractures:



Without doing that much cleaning, I wouldn't have seen the problem. But the more I looked, the more it looked unusual, then possibly bad, then for sure, it was bad.



So, now I am searching for a replacement cover, something less than the $693.29 that Toyota charges for this item, but something that has the proper form, fit, and function, and will do the job for me.

I have also decided to use genuine Toyota parts for replacing the timing chain and two sprockets because what I have read about after market chains and gears has caused me opt for reliability and accuracy of the OEM components. I feel the same about the oil pump and water pump and fan clutch. I discovered that many of these trucks had developed a loud running noise, some describe as like a MAC Truck diesel engine growling. Well, from the first day I owned this truck, its engine sounded to me as if it didn't want to travel on the interstate. It doesn't have a tachometer, but I have driven manual for so many years that it's not a problem to me, so much, but in this case a little because the roar of the engine puts me off a bit. What I have read is that it is the fan clutch (fluid powered) that fails and causes the noise. Thus, I am replacing it with a Toyota replacement, and I am hoping that what I read about the noise is what I now think it is, and when it is back together, it might be a pleasant surprise, not only if it is because the engine has been saved, but that the engine sound will be like any other Toyota engine.

Well, that's it for the BEFORE pictures. Hopefully, I will be able to find time to come back and show you the AFTER pictures, where all of the engine has been cleaned.

Ok, now that I have expended all that energy, how about someone teaching me something I don't know about what I am doing, such as make a prediction that all this work will be for naught. Ha

 

just curious why you did not pull that engine ??

After seeing the valve cover I would have yanked the engine.

Pulled it apart inspected things decided what the next step was.

If it was going back together the Block would be hot tanked to get the oil passages clean.

Best of Luck!

 

Excellent question Bivouac.

1) My engine lifting tool was used on my 1999 Celica a few years ago, then my friend took it to Texas to use on his Tundra, so I didn't have it back at the time I opened the valve cover.

2) I had been inundated with other work at the time. For example, my brother picked up a 2021 Traverse that had a fire in the engine compartment from a state auction and had talked me into letting him use my driveway while restoring it. That had taken the previous 9 months, and I live in a development with an HOA that doesn't like homeowners who do car work in their driveways, causing my time pressure to build.

3) My garage is full like a can of sardines.

4) It took me time to think of just how I might be able to get all the sludge out of that engine, and my original plan was to clean the topside and then use chemicals to flush the engine clean.

5) Second thought after cleaning the valve area was to see how the oil pan looked, and that took time to figure out how I could get it off, considering the cross-member and sway bar that was in the way.

6) My wife had bought me a 5000 lb QuickJack lift that I wanted to use and found a way to lift the Tacoma, despite the lift points not being where the QuickJack could properly get at them (the rear lift points are on each side of the differential, and the two pieces of the QuickJack have to be placed in parallel, instead of running between the front and rear lift points on a diagonal; I solved that problem by using a spot on the lift spring on each side, so the lift could be used in parallel; I called an expert at QuickJack who told me it was appropriate for me to do that).

7) I found an excellent YouTube video of a guy removing the Tacoma timing chain cover without removing the head (part of the procedure in the FSM), and that made me think that pulling the engine really wasn't necessary. And, once I knew about the two head bolts that connect all the way to the timing cover, it came right off. Yes, there is a potential problem reinstalling the cover because the new one's top part butts up against the extended head gasket. I have to be especially careful when doing that.

8) I removed the radiator to give myself enough room to do the work.

9) My current thinking is that I saved a bunch of time, and some money, by not having to remove the head, Certainly, if I had plenty of garage space at my disposal, yanking the engine might have been my very first inclination, because by doing that, I could have sized up any problems right from the get-go, and I could have fixed those problems for certain, as you pointed out, but due to space considerations, and due to the step by step way I entrapped myself, it turned out to be simpler for me to do it the way I did. If I had proceeded as you suggested, I would not have the knot in my stomach from replacing so many parts in a quest that I will not know is going to be successful until I am finally complete. Being able to hot tank the block would indeed have been nice for the reason you stated.

BTW: I am not an expert at this. I have only torn down one engine prior to this, and that was because of a significant overheat which warped the head, and back then there was space in my garage and a next door neighbor who was quite enthusiastic about encouraging me to tear down my Celica engine.

Thanks for the good wishes. I send some right back to you.

 

That marking on the timing cover is just leftover from the manufacturing process. There’s really no need for concern.


A lot of the cast aluminum on cars have sections like that

 

I agree then the flaws get filled with material over the years which makes them stand out.

People who seem to think those parts need replaced are hard to convince otherwise far to often.

Thanks for pointing that out.