Head gasket leaks (1 Viewer)

[neoworm]

275,000 miles and 20 years. Started leaking externally at the back of the PS head as well as just above the engine mounts on both heads. Truck ran fine and an inspection of the cylinder bores didn't give me any reason to believe it was leaking internally but I'm sure it was only a matter of time.

Truck has never overheated or ran particularly hot. I believe the head gaskets just timed out. After 20 years of faithful service they just had enough.

I could have pulled the heads and replaced the gaskets and I'm sure it would have run for another 200k but I had a spare motor built up in the corner of the garage so it's getting replaced.

 

[excessive]

Thats certainly a rare occurrence on the UZ motor. Ive never seen it before or heard of it. You could probably just leave it and be completely fine, as long as its not leaking internally. Just check all throttle body , coolant hoses, and crossover pipes before you rip the heads off

 

[Asanka]

Possibly this?

 

[Rednexus]

That's very similar to a infamous Subaru EJ25 headgasket failure. Those are caused by a combination of poor-quality OEM gasket coating and grounding/electrical issues causing electrolysis in the coolant.

Hoping my 2UZ doesn't end up with the same fate, the job looks a lot harder than the Subaru gaskets which are only a day of work.

 

[neoworm]

Ya at 275,000 miles and 20 years of reliable service I would hardly say the head gaskets were poor quality. It's a gasket, gaskets wear out. It's 20 YEARS OLD. lol! There seems to be this perception that nothing on the 2uzs ever wear out because a select few run for 300k++ miles. There are a lot of these engines out there and based on what I've witnessed over the years I'd venture to guess that 250k to 300k miles is the AVERAGE lifespan.

300k+ would have been nice but I don't feel like this thing owes me anything. She's getting a fresh engine and hopefully it'll run for another 275k

 

[Rednexus]

Does the UZ use a coated gasket or a multi-layer steel gasket? Subaru's (which rarely make it past 100K before leaking) had a coated steel gasket where the coating was slowly dissolved by the coolant/oil. Later versions of the engines fixed that with MLS gaskets, which are much more inert and don't have that problem. If it is a coated gasket, I can't help but wonder if coolant chemistry is affecting it - and if so - what needs to be done to keep the same failure form happening in other 2UZs (more frequent changes? checks of coolant pH?).

 

[neoworm]

Does the UZ use a coated gasket or a multi-layer steel gasket? Subaru's (which rarely make it past 100K before leaking) had a coated steel gasket where the coating was slowly dissolved by the coolant/oil. Later versions of the engines fixed that with MLS gaskets, which are much more inert and don't have that problem. If it is a coated gasket, I can't help but wonder if coolant chemistry is affecting it - and if so - what needs to be done to keep the same failure form happening in other 2UZs (more frequent changes? checks of coolant pH?).

It's a coated multi layer steel. There's a big difference between failing at 100k and failing at 275k. lol I would guess it was 20 years and 275,000 miles of heating and cooling cycles that affected it.

 

[Rednexus]

It's coated. There's a big difference between failing at 100k and failing at 275k. lol

Agreed, but I don't want my head gaskets to fail at 275K . If there is something I can do between 175K and 275K to keep that from happening I'll do it.

 

[neoworm]

Well odds are good you'll get at least 275k.

 

[Rednexus]

I want 475K .

Ordered a pack of these to keep up on the pH. Keeping it close to 7 should reduce coating erosion.
Amazon product ASIN B0753MZT7P

 

[Asanka]

There are plenty 300k+ and a few 500k+ LC100s in this forum. This is not a common issue or at least an issue that needs to be kept an eye on. Also, there was a 730k mile truck here with no history of engine issues.

Maybe using Toyota coolant and following the recommended replacement intervals is good enough.

 

[SaturnAscends]

I'm guessing the OP being in Canada has something to do with this. All that road salt may have caused some corrosion of the head gasket material over time.

 

[neoworm]

I'm guessing the OP being in Canada has something to do with this. All that road salt may have caused some corrosion of the head gasket material over time.

Nice try but the truck's never seen road salt.

There are plenty 300k+ and a few 500k+ LC100s in this forum. This is not a common issue or at least an issue that needs to be kept an eye on. Also, there was a 730k mile truck here with no history of engine issues.

Maybe using Toyota coolant and following the scheduled replacement intervals is good enough.

That's just conjecture on your part.

According to Toyota they sold 183,138 100's in NA during it's 9 year production run. The "Post you high mileage 100" thread is 69 pages long. So at best that's 69 trucks that have exceeded 300k? For arguments sake let's say there are 1000 trucks documented on this forum that have gone beyond 300k. That's 0.5%.

I'm no statistician but my gut is telling me that just because a bunch of people on IH8MUD have had trucks go beyond 300k before needing a head gasket or two, it doesn't mean that is the norm.

The 100 series is an awesome truck but there is a lot of Kool-Aid being drunk around here. HAHA.

FYI my truck has only ever had Toyota coolant and it gets replaced every 2 years regardless of mileage because that's just what I do. So I don't think lack of maintenance was an issue. At 20 years plus things get tired.

 

[SaturnAscends]

Nice try but the truck's never seen road salt.


That's just conjecture on your part.

According to Toyota they sold 183,138 100's in NA during it's 9 year production run. The "Post you high mileage 100" thread is 69 pages long. So at best that's 69 trucks that have exceeded 300k? For arguments sake let's say there are 1000 trucks documented on this forum that have gone beyond 300k. That's 0.5%.

I'm no statistician but my gut is telling me that just because a bunch of people on IH8MUD have had trucks go beyond 300k before needing a head gasket or two, it doesn't mean that is the norm.

The 100 series is an awesome truck but there is a lot of Kool-Aid being drunk around here. HAHA.

FYI my truck has only ever had Toyota coolant and it gets replaced every 2 years regardless of mileage because that's just what I do. So I don't think lack of maintenance was an issue. At 20 years plus things get tired.

It also depends on how it's driven. A highway commuter driven for long distances with minimal heat cycles will last a lot longer than a grocery getter, all else being equal. Look at long-haul truckers; they routinely see a million miles on the original engine, in part cause it'd constantly being driven.

 

[neoworm]

It also depends on how it's driven. A highway commuter driven for long distances with minimal heat cycles will last a lot longer than a grocery getter, all else being equal. Look at long-haul truckers; they routinely see a million miles on the original engine, in part cause it'd constantly being driven.

For sure, and I would bet most 100's are grocery getters.

I shouldn't be saying "trucks going beyond 300k" I'm talking about head gaskets. Head gasket failure isn't the end of the truck. At least it doesn't need to be. Yes 100's will go well beyond that I'm just saying that I don't think the expectation should be that the 100 series head gasket is going to last to 500k.

Sure maybe some do but I bet most don't

 

[neoworm]

I can only imagine what goes through the mind of a Land Rover driver when he comes across a thread of Land Cruiser nerds debating whether or not a head gasket leaking at 275k and 20 yrs constitutes a premature failure or not.

 

[Rednexus]

Being that there are lots of 20+ year 2UZs around I'm wondering if this is restricted to poor coolant chemistry or a small batch of OEM gaskets. Lots of Tundras and GXs are of similar age and miles without this issue so it's abnormal.

Anything short of 500k trouble free miles for a UZ is unacceptable

 

[nissanh]

Did you own this truck since the beginning? May be someone washed the engine with chemicals to keep it clean? Man, I don't want a head gasket leak, but if it happens, I don't mind doing it as I did my first head gasket job on a 4 cylinder and it lasted 100K miles and cost only $300 (including a head job)! Did it again with OEM parts and still kept the price below $200 (no head wrapage on the second round).

 

[jLB]

Nice try but the truck's never seen road salt.


That's just conjecture on your part.

According to Toyota they sold 183,138 100's in NA during it's 9 year production run. The "Post you high mileage 100" thread is 69 pages long. So at best that's 69 trucks that have exceeded 300k? For arguments sake let's say there are 1000 trucks documented on this forum that have gone beyond 300k. That's 0.5%.

I'm no statistician but my gut is telling me that just because a bunch of people on IH8MUD have had trucks go beyond 300k before needing a head gasket or two, it doesn't mean that is the norm.

The 100 series is an awesome truck but there is a lot of Kool-Aid being drunk around here. HAHA.

FYI my truck has only ever had Toyota coolant and it gets replaced every 2 years regardless of mileage because that's just what I do. So I don't think lack of maintenance was an issue. At 20 years plus things get tired.

I guess I should start preparing my “for sale” ads…

Although I do find it interesting, that my 115k mile original owner 06, and 280k mile 2nd owner 99, seem very different from my son’s 150k mile 3rd owner vehicle…

 

[UZJ100LC]

Nice try but the truck's never seen road salt.


That's just conjecture on your part.

According to Toyota they sold 183,138 100's in NA during it's 9 year production run. The "Post you high mileage 100" thread is 69 pages long. So at best that's 69 trucks that have exceeded 300k? For arguments sake let's say there are 1000 trucks documented on this forum that have gone beyond 300k. That's 0.5%.

I'm no statistician but my gut is telling me that just because a bunch of people on IH8MUD have had trucks go beyond 300k before needing a head gasket or two, it doesn't mean that is the norm.

The 100 series is an awesome truck but there is a lot of Kool-Aid being drunk around here. HAHA.

FYI my truck has only ever had Toyota coolant and it gets replaced every 2 years regardless of mileage because that's just what I do. So I don't think lack of maintenance was an issue. At 20 years plus things get tired.

69 pages long with about 20 posts per page…
And mud is also a small subset of the community.