Name that leak

[linuxgod]

Valve cover gasket? Seems odd if it is that the gasket leaked across the engine bay, unless the fan is spraying it all over the place. Engine oil is full, but there's definitely residue on the lower part of the engine that looks suspiciously like oil

I noticed this when checking the truck this evening, looking for any signs of why my engine oil and transmission temps were higher than normal when towing last weekend.

This is looking down into the engine bay, so radiator at the bottom of the pic, battery to the right, that thing across the top and to the right is the radiator hose.

 

[BVE]

AC line spraying?

 

[linuxgod]

AC line spraying?

Possibly? A/C seems to be working just fine though

 

[CruiserFan88]

If it was the A/C line I would expect to see the residue on the line itself around the metal fitting where it attaches to the rubber hose. From your photo that looks clean. Looks awfully similar to valve cover gasket leaks I've seen before. I would take a minute to clean the area and tighten up the valve cover bolt in that corner. Its likely a small condensation leak from the gasket. On the Gen 1 Tacomas, you have to regularly re-torque the valve cover bolts due to the washer that is used. I have not had to do this on my 200 though, nor have seen this as a common occurrence on this board.

 

[linuxgod]

If it was the A/C line I would expect to see the residue on the line itself around the metal fitting where it attaches to the rubber hose. From your photo that looks clean. Looks awfully similar to valve cover gasket leaks I've seen before. I would take a minute to clean the area and tighten up the valve cover bolt in that corner. Its likely a small condensation leak from the gasket. On the Gen 1 Tacomas, you have to regularly re-torque the valve cover bolts due to the washer that is used. I have not had to do this on my 200 though, nor have seen this as a common occurrence on this board.

Ok thanks, I did clean it up as best I could this morning, but I'll try to retorque that bolt as well. Torque spec looks pretty low (9 ft lbs)

 

[linuxgod]

FYI I cleaned this up a bit with a rag so I'll see how it looks in a few days of driving. A short trip to Home Depot didn't turn up anything useful.

Given there's only a little oil at the bottom of the valve cover seal, but lots more to the left behind the compressor pulley, I'm actually wondering if this might be a leak in the timing chain cover, and any residue I'm seeing around the front of the head is just a bit of oil dripping being misted by the radiator fan.

Even after wiping the hard pipes and as much of the bolts etc I could reach down behind the belt, you can see the majority of the oil seems to be along the front of the block.

 

[CharlieS]

Looks like it has been wet for a while, given the build up. I wouldn’t think it’d be that thick if it was a spill from someone filling the oil during an oil change.

Can you get to it well enough to spray the residue and grime off with something like brake cleaner to see if it a visible leak/weep returns after some driving? That may give you additional info to work with.

My halfway across the country diagnosis is likely a weeping valve cover.

 

[linuxgod]

Looks like it has been wet for a while, given the build up. I wouldn’t think it’d be that thick if it was a spill from someone filling the oil during an oil change.

Can you get to it well enough to spray the residue and grime off with something like brake cleaner to see if it a visible leak/weep returns after some driving? That may give you additional info to work with.

My halfway across the country diagnosis is likely a weeping valve cover.

I agree, seems like a very slow drip.

I actually tried but my can of brake cleaner was just about out so the ~2 seconds of spraying did virtually nothing, hence just wiping it with a shop rag. Need to hit autozone for another can.

Valve cover seems plausible. It's also probably the cheapest thing to fix, so I kinda hope that's it. The flat rate manual indicates 1.4 hours labor for both sides, I think. Or maybe it's 2.7 hours total? I can't entirely tell what the difference is between "assembly" and "gasket".

 

[bloc]

Chain cover. My 2013 has the exact same leak only it has progressed further.

One of these days I'll tear it all down and fix it.. and throw new tensioners in while I'm at it. For now a good degreasing around each oil change gets the job done.

 

[linuxgod]

Chain cover. My 2013 has the exact same leak only it has progressed further.

One of these days I'll tear it all down and fix it.. and throw new tensioners in while I'm at it. For now a good degreasing around each oil change gets the job done.

Meh. That's a much more expensive proposition. Just for that reason I like @CharlieS's opinion better!

That said it feels more likely it is the timing chain cover given most of the oil seems to be underneath the head and down the side of the block (aside from the small amount in the corner of that valve cover)... but I hope it's not

FRM says 6.6 hours just for the timing chain cover. Probably closer to 9 hours since at that point I want to do the tensioner etc too since it's all apart. At 111k throw in the water pump too and suddenly I'm thinking I'll just clean it and keep an eye on the oil level for now...

 

[bloc]

and suddenly I'm thinking I'll just clean it and keep an eye on the oil level for now...

View attachment 2685219

I despise oil leaks. The fact that I’ve let this one ride as long as I have is a testament to the inconvenience of addressing it.

 

[tincan45]

Yuk...looks like it's been there a while. Spray it down with some simple green, let soak, and rinse. At least it will look good until you get all the parts together for your 120K service!

 

[CharlieS]

@tincan45 I seem to recall that regular Simple Green is not good for aluminum, if you do use simple green , maybe get the aircraft version that is safe for aluminum.

 

[tincan45]

@tincan45 I seem to recall that regular Simple Green is not good for aluminum, if you do use simple green , maybe get the aircraft version that is safe for aluminum.

I hadn't heard that. You got me curious so I googled it. Sounds like it "might" be an issue if you leave it on too long or don't flush it out well.

Simple Green FAQs

Find frequently asked questions and answers about Simple Green, the non-toxic, biodegradable, environmentally safer cleaning product.

simplegreen.com

 

[CharlieS]

Yep, the one I saw said less than 10 minutes is ok (maybe the same one you linked?). But spraying it on to soak for a while seems like maybe not a great idea? Who knows, it’d probably be fine.

 

[linuxgod]

If 15 minutes of Simple Green will destroy your engine, you best keep that garage queen locked up. I imagine all the salt spray from the crap they use on the roads here is far worse.

 

[tincan45]

If 15 minutes of Simple Green will destroy your engine, you best keep that garage queen locked up. I imagine all the salt spray from the crap they use on the roads here is far worse.

In that case, I imagine the oil is probably a really good protectant and you should never fix the leak. Will be like an old tractor with an inch thick layer of oily goodness.

 

[linuxgod]

In that case, I imagine the oil is probably a really good protectant and you should never fix the leak. Will be like an old tractor with an inch thick layer of oily goodness.

I’m hoping it’s thick enough it’ll act like stop leak

 

[TLC2013]

@linuxgod did you ever get to the bttom of this? I recently noticed the same build up of oil in the exact location on my 2013 with 102k.. Hoping it's just the valve covers. Planning on taking a further look into it over the weekend.

 

[CruiserFan88]

After looking at post #6 pics, i'd have to change my stance to chain cover. I would expect the valve cover bolt to be this saturated if it was indeed the valve cover. The bolt in post #6 is likely the culprit that is weeping and then the fan is blowing it up and explains why its a drier 'stain' closer to the covers. Otherwise, I don't believe gravity would cause it to be so saturated at the bottom. This is a good one..