[Nosepicker]

Hi guys,

I'm trying to help out my mom who's on a fixed income. I believe there's an oil leak behind/rear of the head.

I've searched YT and here, and I can't find any How-to DIY Head Gasket Removal/Replacement? Is there no DIYs for this other than swapping out the entire engine and/or having a mechanic perform this?

Correct me if I'm wrong but from what I've read/seen these 1st Generations are a ticking time bomb. If it's not the head gasket then it's the oil line.

Thanks in advance for your input.

 

[ronthehammer1966]

Have you checked if the oil leak is coming from the valve cover?

 

[Nosepicker]

Have you checked if the oil leak is coming from the valve cover?

Yes, and no it's not coming from the valve cover. I replaced the valve cover gasket some months ago and it's not leaking.

And I don't see any oil sludge in her radiator reservoir or lines. I'll have another look at the leakage.

The car's running great. No issues. No CEL. Nothing other than the leak. I'm trying to take a preventative approach.

The car's got 107K miles and it's a 2007 Highlander (base model).

 

[katekebo]

Head gasket is a major job and I would not recommend anybody who doesn't have significant experience as mechanic to attempt it. You will need specialized tools like a torque wrench and precise instruction for the order in which the head bolts need to be tightened. A generic video from a different vehicle may have a different sequence and torque specs and you will end up with a failed head gasket that may ruin the engine if coolant mixes with oil.

Also, oil leaks can come from different places, as mentioned above by @ronthehammer1966 . Valve cover is one of the most frequent places. Actually, oil leaks due to failed head gasket are pretty rare.

 

[Nosepicker]

Okay, I took some pics. I believe the oil leak is coming from the left side of the head behind the pulley. I'm not all that familiar with the Highlander's layout so would appreciate it if you guys could shed some light. As a reminder, I don't see any oil sludge in her coolant or lines and the car runs great, with no high temps, no CEL, no engine issues whatsoever except for this oil leak.

I have a feeling this oil leak is going to get worse if I don't do anything about it.

Is this leak from the head? Let me know what you guys think. My mom would be greatly appreciative if you guys can help guide me to fix it unless it's a leaking head gasket.

 

[katekebo]

Suggestion - buy a can of brake cleaner spray and clean the area thoroughly. By now the oil has already spread to a large area, making the identification of the source difficult. If you clean / degrease the area and inspect it a few weeks, it should be much easier to pinpoint where it's leaking from.

 

[Nosepicker]

I can see the trail. It's mainly coming from behind the pulleys. What's behind there? Water pump? Engine head gasket?

I'll try to clean it tomorrow but getting the spray bottle in those tight spaces to clean the oil is going to be a challenge. I suppose I can spray it on a rag and wipe it down. I'll give it a try but pretty sure it's coming from behind the pulleys.

 

[Mgeorge]

It’s not hurting anything, just leave it. It’s not the head gasket.

 

[kenny-bob]

Looks like the valve cover gasket is leaking up at the timing chain cover and running down from behind the pulleys. What brand of VC gasket did you use for the replacement?

i see 1 drop on the power steering pump; wipe it off and see how long it takes to form again.

You need to start looking and take pictures from the top side and work your way down.

 

[Nosepicker]

It’s not hurting anything, just leave it. It’s not the head gasket.

Hmm...mmmmaaaayyybe.

Looks like the valve cover gasket is leaking up at the timing chain cover and running down from behind the pulleys. What brand of VC gasket did you use for the replacement?

i see 1 drop on the power steering pump; wipe it off and see how long it takes to form again.

You need to start looking and take pictures from the top side and work your way down.

Thanks for your input.
I've checked so many times and it's bone dry. I'll check one last time thoroughly tomorrow. I used Fel-Pro valve cover gasket.

 

[kenny-bob]

Maybe water pump is leaking--that lowest bolt is wet with a trail down from there.

Where was the valve cover leaking before?

Get some baby powder and put some in your palm, then use a straw to blow puffs of powder onto all the leaky spots; it will stick to the oil and leave a white film, then when you drive it some a leak will be easy to see with the fresh oil.

 

[Nosepicker]

Okay, so I couldn't sleep because the thought of questioning my work (I'm somewhat mechanically inclined) drove me crazy. I check, double-check, triple-check, and then check all my checks for all my work. So, I went out in the middle of the night, freezing my ankles...haha...and checked the valve cover gasket. There is not one drop of oil from the valve cover gasket. It's bone dry. So, let's put the valve cover gasket to rest.

I don't think it's the water pump. It's oil residue, not coolant.

I'll clean the oil residue off tomorrow and check for an oil leak in a few days. I'll give the baby powder method a try.

Thank you for all your input. See you in a few days.

 

[kenny-bob]

Maybe failure of the gray sealant for the timing cover to the block behind the tensioner pulley?

But it seems to be a fairly slow leak to only be showing like that after 100k miles and 16 years.

It is a lot of work to get everything off (belt, alternator, water pump pulley, crankshaft pulley [$pecial tool], exhaust, top and bottom motor mounts, power steering pump, tensioner) just to remove the timing cover for such a small slow leak.

But if you do all this, then replace also the thermostat, water pump, VVT oil filter, motor mounts, serpentine belt, etc.

Less costly to just do a good scrub and clean it up all shiny, then monitor the leak flow rate to know how bad it is.

If you replace the water pump and don't diligently bleed out the air, then it's possible to overheat the engine; if that occurs you will be needing to replace the head gasket, and head, or engine--don't ask me how i know...

 

[Nosepicker]

Maybe failure of the gray sealant for the timing cover to the block behind the tensioner pulley?

But it seems to be a fairly slow leak to only be showing like that after 100k miles and 16 years.

It is a lot of work to get everything off (belt, alternator, water pump pulley, crankshaft pulley [$pecial tool], exhaust, top and bottom motor mounts, power steering pump, tensioner) just to remove the timing cover for such a small slow leak.

But if you do all this, then replace also the thermostat, water pump, VVT oil filter, motor mounts, serpentine belt, etc.

Less costly to just do a good scrub and clean it up all shiny, then monitor the leak flow rate to know how bad it is.

If you replace the water pump and don't diligently bleed out the air, then it's possible to overheat the engine; if that occurs you will be needing to replace the head gasket, and head, or engine--don't ask me how i know...

I was up till 2:30am this morning watching YT vids and I found two vids that looked very similar to what I'm experiencing and it's exactly what you pointed out above: "...gray sealant for the timing cover"

I believe this is what it is. And you're right. It's a lot of work for such a small slow leak.

Waiting for my mom to come home so I can clean it up and confirm our suspicion.

 

[Nosepicker]

BTW, after all the vids I watched all last night, the consensus is that the 2.4L 2AZ-FE engine is by far the worst design Toyota has ever come up with. And I'm starting to agree with them having worked on Hondas and other Toyotas.

 

[Gugi53]

Clean the area and make new pictures. In this way is hard to say. My gest, its from hose, but I can be wrong.

 

[Ralph Spoilsport]

You might try looking for info from the Camry community, for instance, where the four cylinder engine is more common.

If it isn't the valve cover, my next thought would be the timing cover.

 

[BillDurham]

Guys, any parts store will sell you a UV dye leak detector kit. Sport for one with the black is going to hook to the battery, not just a flashlight. Clean the engine, add the recommended amount of dye to oil, drive it for a week. And that leak is a drip, yes messy but not oil under pressure or it would be everywhere. The 2.4 with cracked block issues were USA made, 2008 ish.

 

[Jeff83]

Okay, I took some pics. I believe the oil leak is coming from the left side of the head behind the pulley. I'm not all that familiar with the Highlander's layout so would appreciate it if you guys could shed some light. As a reminder, I don't see any oil sludge in her coolant or lines and the car runs great, with no high temps, no CEL, no engine issues whatsoever except for this oil leak.

I have a feeling this oil leak is going to get worse if I don't do anything about it.

Is this leak from the head? Let me know what you guys think. My mom would be greatly appreciative if you guys can help guide me to fix it unless it's a leaking head gasket. View attachment 412047

View attachment 412048

View attachment 412049

Get 2 or 3 cans of brake cleaner and soak down the whole area starting from the top close to the valve cover. Oil runs downhill so the leak is most likely above the pulllys that you are looking at. When you installed the new valve cover gasket did you use RTV in the corners where the cover goes up and over the camshaft? That area will leak if you didn't do that. Bad head gaskets don't leak oil like that if at all. If you see some crust around the area where the head meets the block and is the same color as your coolant THEN you might have a bad head gasket.

 

[Nosepicker]

I tried my best to clean all the dirt and grime off. Some tight areas I wasn't able to fully clean but for the most part, it's dry and somewhat clean. I think this is good enough for me to detect where the leak is coming from. Using the oil dye would have been ideal but it's too late now because mom had to use the car. I'll have to wait a few days to examine the area(s) for leakage. Anyhow, below are before and after pics.

BEFORE:

AFTER:

*Disregarding any "valve cover gasket" questions. Please refer to post #12.