I just bought an 03 Taco, 3.4L 4x4 from a reputable local dealer. It was neglected but not abused and has 148K on it, and I have since dropped a ton of cash into it baselining back into top notch condition. One of the shops I took her to said that the engine was "sludged", and that with frequent (every 3K miles on the dot) careful oil changes this would take care of itself. Not to use Seafoam or any of that type of thing. The other shop (more of a Toyota specific off road shop) said they didn't see any sludging, but they didn't have the vavle covers off, and the only way to take care of it was to drop the oil pan and the take off the valve covers and do it by hand.

I've been around trucks my whole life and I've never heard of a "sludged" engine. If it is in fact sludged, is this something that I have to address ASAP? The truck runs like a Singer sewing machine - smooth as glass.

Would something like Marvel Mystery Oil help to clean up thick oil deposits? I have to say, I don't believe in Seafoam, but I'll defer to the judgement of wiser heads than mine.

Thanks for any help.

 

Pull the covers at least and with a shop vac and a brush, scrape off what you can. Then start running a synthetic oil. It will start cleaning it on its own and eventually it will be nice and clean inside.

 

Cool, thanks. They did valve cover gaskets and I guess that's when they saw it. I'm running synthetic now.

 

watch the oil, it will color quickly. You may want to change it at 3k first 2-3 changes. Then you can taper off to 4k then 5k. I had a really dirty motor with mild sludging up top. Cleaned what I could and when I pulled the covers 40k later for paint, the motor looked almost new under the covers.

 

I bought a 4Runner with rod knock deliberately to replace the engine. The original was sludged so bad that you could literally peel the oil off the insides.

 

What causes that? Not changing the oil enough? Thanks for the replies.

 

Put a quart of diesel in the oil. Run it for 10 minutes warm. Drain oil. (read up a bit on it first) Most engine flushes are 90% diesel.
Fill with new pretty oil.

And done.

 

Excellent - thanks.

 

https://www.yotatech.com/forums/f2/o...ttacks-167704/

 

MMO is supposed to slow dissolve the sludge. I would suggest oil filter changes every 500 miles for the first 3000 miles. The thing you absolutely do not want to happen is for the filter to clog and starve the bearings.

 

How do you figure?

 

Pop the oil cap and see what's inside.

 

Well, I did - and I can see sludge, so that settles that. It was about 1/2 quart low after the last oil change so I added most of a quart of Marvel Mystery Oil to it. I'm due for an oil change in a week or so anyway - pretty much on the 3K mark - so that'll give it a few days to start work. I may continue with MMO or try the BG products. All the various treatments sound like different flavors of the same thing.

Jeez, I had no idea this was even a thing. I've never heard of it until now, and the pictures make me sick to my stomach. Hopefully no oil races are clogged - it runs cool and smooth and will bark the tires if you punch it. So we'll see I guess.