1st gen sludge in the valve cover 130k miles

Thanks, I appreciate your comment. I am no expert in how aluminum castings are supposed to look, but the worst one, the one I tried to highlight, it seems to me is an actual crack in the metal. It continues on down several inches along that surface until it hits a more solid structure (a thick wall), just like a crack would. And on the flip side of the casting, you can see an impression that suggests that the crack goes almost all the way through the material.

A close look at the metal surface shows numerous small "hairline" cracks, almost all of which are along the water passageway, and they look (to me) as if formed by metal fatigue after 23 years of heat cycles from being used in the Tacoma, and the water passage just might break up in chunks some time in the future if I continued to use it. That's how I had been interpreting them until I read your comment.

if an artifact of the manufacturing process, they formed during the cooling process of the molten aluminum, right? And quality control let it pass. And your experience says that happens reasonably often.

I had considered taking the casting to a local machine shop that I found recently. Liked the guy; think highly of him. Maybe I will follow through with that idea and let him take a look. Thanks for alerting me. There is nothing to loose, except time, from seeking a skilled a second opinion.

 

I just found evidence that you are correct. If I can figure out how to post this photo, it is snipped from an enlarged photo of the AISIN timing chain cover made for my Toyota, and I believe shows exactly what you described.



Clearly these are surface artefacts that are very similar to those I see on the backside of my timing chain cover. I cannot understand why they seem to associate only with the water passageway, unless it has to do with the non orthonormal sweep the passageway traverses, but there they are anyway, in a supposedly brand new aluminum casting. I would have thought that the manufacturer would have selected a better specimen to put on display.

Thanks again for your help.

 

Well, a lot has happened since I first began my oil sludge cleaning up by hand without taking the engine out of the truck project.

At the moment, I have the transmission out and am going to replace the rear main seal. Way back, at the very first evidence of the truck having an oil leak, I had visually determined that the rear main seal was leaking oil. I wasn't completely sure, but there seemed to be evidence of that. We put a plastic mat under the engine to collect any drips, and it continued to collect oil for several years, up to the point where I had to take the valve cover off, because I feared the leaking oil spilling onto the exhaust manifold might cause a fire (so much smoke billowing out), and with the valve cover off, I discovered the sludge. That's where this project started.

BTW: Getting the transmission out without taking the engine out is a dicey proposition in this particular truck (2000 Tacoma 2WD regular cab 5-speed MT 2RZ-FE 2.4L engine) because the cross-member that rides under the rear of the transmission is welded to the frame and cannot be removed (as is typically done) so the transmission cannot just drop down, hence getting the transmission out, once it has been separated from the engine, is a process (defined in the FSM), and it is tricky, especially if you have never done it before. But, it is out and I have gotten the "Engine Rear Oil Seal Retainer" off. I started to clean it so I can install a new seal.

I discovered intrusion of discoloration (presumedly aluminum oxide) on the lower edge of the round polished sealing surface, somewhat damaging that surface. I need advice about whether or not to replace this part in order to guarantee a good oil seal. I don't know what is needed to form a long-lasting oil seal with aluminum and am looking for somebody who knows and can tell me to buy a new one, or not. I have used Scotch-Brite to rub the surface to try to bring back the polish, but nothing stronger. And I didn't work on it very long.

 

i think a red brillo pad will def get that surface better
as you said....dont go crazy
i think i have some pix of my cam carriers from another vehicle
i will post b4/after pix shortly

 

Before /after

 

Appreciate your reply, ControlCar. When you said brillo pad, I was thinking of the soap impregnated steel wool pads. If I understand your pictures, you seem to have used scotch brite, like I was using, only the color of my scotch brite was blue (soft) and yours is red, or red-ish, which probably has aluminum oxide particles in it (more abrasive). That's a good idea. (are your photos in reverse order, as the after seems to have scratches and the before doesn't?) Here is a photo of the blue that I was using.



Ok, you are suggesting that I use a little abrasion to polish the sealing surface to get rid of the oxidation?

Scotch Brite comes in different colors that indicate the amount of abrasiveness they can provide.



If I am understanding you, I should be able to select a Scotch Brite pad with just enough abrasiveness to enable me to remove all of the finish mess and get down to a nicely polished aluminum sealing surface.

That is where I had a problem in my thinking. I was wondering first whether the existing surface would lead to oil leaking if I just used it as it is and put a new oil seal into the retainer.

My next thinking problem is that if I managed to polish off the entire sealing surface, and then pressed a new seal into the retainer, the diameter of the opening would be slightly larger than before I polished it out, and I was thinking that might not be such a good idea, considering that the seal goes in dry and is pressed into position. Do you know if the tolerances generated by that approach would still permit making a long-lasting oil seal? This afternoon was spent searching for a new retainer, but if the polishing will not lead to more oil leaking, I would be ok doing that. Trouble is, I just do not know for certain, and once I do that job and put the transmission back in place, I really don't want to have to do it all over again. The original seal began leaking a few years ago, but the Tacoma is now age 24, which means that seal lasted a long time as it came from the factory.

That's all I can tell you at this point. I do thank you for the advice.

 

1-a machinest told me about ‘red brillo pad’ was best BUT quote: “less is more”
DONT hulk it scrubbing surface
I used brake cleaner as lubricant
Seriously 4-5 light pressure even passes on cam carrier surface. Took out that scoring
Now on that cam carrier, my choice was get scoring out as best I could or buy new $2600 head(tht small part not available unless assembly bought)
It worked.
2-yes, before/after pix got swapped somehow
3-remember, my use was metal to metal
Cam (forged steel) to cam carrier(soft aluminum)…..much less tolerance for a screwup from taking too much material off mating surface
In your case rear seal(rubber) that needs to be tapped in to aluminum
You have crap ton more ‘wiggle room’ than I did
I agree with you that current seal mating surface needs to be cleaner
If not, over time, that is where the leak will start
I also like your idea of using pads like sand paper….start out rough finish with fine
Man for seal surface, I wouldn’t rule out using 1000-1500 grit sand paper LIGHTLY as 1st step

 

4-last trick is IF you thick u screwed up surface with too much sanding
(Hopefully not an option)
Ugh…..this is bringing back so many bad memories…..

again, $2600 or get it the best I could.
Drill bit dinged my cam seal cup/surface
Ahhhhhhhhh

this is after a shit ton of 1500 grit sanding

 

Again I went back to machine shop
This front carrier part too small, would likely warp if alum added with heat/sanded.
Owner said to do this

 

Then sand smooth

 

And for added security
Thin layer of Fugi Bond(high quality RTV) around cam seal
Manual advised to only use thin coat of mineral oil on tapped in cam seals

I had no choice. did that to affected/sanded cup and other 3 other cam seals tapped in per manual
Good to go
4yrs running
GL

 

What is that liquid you were told to use as an aluminum filler? Where did you get it? How long did it take to dry? How easy was it to sand smooth? Would you recommend using it for fixing general dings in aluminum? Getting that repair to hold up for 4 years without leaks is good to know about.

And, if I understand what you did, and please correct me if I am wrong, you applied a coat of Fugi Bond (RTV) around the seal's seated edge (OD edge of the seal) before tapping it in place, instead of a "thin coat of mineral oil"? Did you do that to cover up possible imperfections in your sanding operation of the aluminum sealing surface, or to fill in for any extra room you might have created by sanding? You are working with CAM seals.

I am working with the rear CRANKSHAFT seal. As I understand the FSM (and this is true for both of the CRANKSHAFT seals), when you tap the seal (90311-88003) into the rear main seal retainer, you do it DRY. No lubricant is applied to the outer ring of the seal or the aluminum sealing surface, the part of the (static) retainer that touches the seal. They call for multipurpose grease to be applied to the crankshaft (journal) as well as the lip of the seal before sliding the seal/retainer assy onto the shaft. . . and they say you need to be very careful not to damage the lip.

I just spent time searching for the material with which the 90311-88003 Toyota seal is made, to get a better feeling about why it is installed DRY. The Google AI helper was able to say that Alibaba says the material is from a list of materials: NBR, FKM, FPM, Silicone, EPDM, but didn't mention PTFE (polytetraflouroethylene -- TEFLON), which is what I thought it was made of. When I specifically asked the AI if it was made of PTFE, it said YES, and then went on to say it was made of MVQ a silicon rubber material. Nowhere did I find what Toyota has to say about the materials that go into making its seals. Do you know of anywhere information can be found about the materials with which Toyota components are made?

I'm liking what you did on your cam seal aluminum areas, and think that maybe I should give it a try before just ordering NEW. I think I might try to use that black waterproof sanding sheet material that has very fine grits, like 400, 600, 800, 1000, 1500 and so on, and wet sand the discolored areas to see if I can't polish it out, since I already have a lot of it laying around, and I kind of know how it will turn out. Thanks so much for your help. At least I can move ahead on this problem.

 

Bc I can’t even post pix in correct order….
I will try my best

1-tht black pin drip was epoxy….for metal
I Let sit 24hrs and then did the best I could to sand gently the curvature to match the aluminum

2-yes, you are spot on (I’m glad I explained it correctly)
Despite manual saying No RTV only oil,
I added thin layer just to prevent my not ‘exact’ sanding process…..bc of my screw up

3-agree with the TSM process as posted

4-seals…..4yrs later I still have PSD thinking about this struggle

this was the first round of cam seal replacements
I literally spent over $100 on seals $7 a pop
I can now do a T belt change on Subaru 25SJ in 2.5 hours (with coolant drained)

 

As far as material
I dunno
But I did learn that all seals basically look/perform the same
But
Manufacturers have a plethora of ways to tap/press on
Dry
Oil
Grease
Assmy lube
RTV
IMO…..just tap on lightly and flush to carrier…..whatever method works for you

5-I think your job is to get that seal mating surface as clean/smooth as possible
If you take it easy and not use a grinding machine…..you will be fine
Remember, the seal has to be ‘forced’ into place
I HIGHLY doubt that you will sand away so much that seal would not touch mating surface

 

11 used seals, OMG. . .

Steven, your last paragraph makes a lot of sense to me. I am going to try that before considering buying a new retainer. Might take a bit of time to do it right, but that's only effort expended, not money.

I counted 11 used seals laid out on your work-bench, and some of them seemed to be coated with the Fugi Bond (RTV) you were talking about. All those seals came from your Subaru 25SJ, from that aluminum cam carrier assembly you were showing the divot you repaired with epoxy? They came from the same vehicle? I have a couple of questions.

First, my Tacoma has a 4 cylinder engine and under the valve cover live the two cam shafts (Input and Exhaust). There are no seals like yours living in there. In fact, the only seals like yours on my engine are the two I mentioned, the front and rear crankshaft seals. That makes me think that your Subaru is a V-6 or V-8, so it would have two cylinder heads, and each would have two cam shafts with seals on each end, maybe, if it has overhead cams? If so, that accounts for 8 of the 11 seals. You mentioned that you can replace the timing cover on your Subaru in 2.5 hours. Do you have to replace all of those seals each time you replace the timing chain or belt?

If that is correct, what are the other 3 seals doing? If you had to polish all of the sealing surfaces for 11 seals, that might account for your talking about having PTSD from doing that job. Before I keep thinking of how horrible that would be, maybe you should straighten me out on where the seals go in your engine.

Second question: you used the RTV on more than one seal, when I thought you only repaired one divot. What was the purpose for using it on the other seals?

Final question: what was the epoxy you used to repaid the divot in the aluminum? I have used JB Weld a number of times, but it isn't a liquid like what you showed.

Bottom line: I sympathize with you in having to change out 11 seals in the engine of your car. The way I am obsessing over a single, but important seal, my rear main seal (cause to get to it requires removing the transmission) must seem rather silly to you, obsessing over getting 11 seals installed but not a single one leaking. Congratulations on getting that job done!