Head gasket - permanent fix?

[Gecko123]

Was the original gasket of poor design or quality, so once it's fixed the problem so goes away and does not come back until a reasonable amount of mileage. Is this correct?

 

[DC runner]

The issue surrounds a particular cylinder and the cooling system. Aluminum is an awesome alloy, but it is no where near as predictable as old fashioned iron. One engines that tend to have these type of problems; it usually centers around an internal cooling channel design that doesn't quite cut it for one part of the block.

You can strengthen the gasket, sure, but it would take a new block that is redesigned to actually fix the underlying problem.

 

[BlackWorksInc]

The issue surrounds a particular cylinder and the cooling system. Aluminum is an awesome alloy, but it is no where near as predictable as old fashioned iron. One engines that tend to have these type of problems; it usually centers around an internal cooling channel design that doesn't quite cut it for one part of the block.

You can strengthen the gasket, sure, but it would take a new block that is redesigned to actually fix the underlying problem.

There doesn't seem to be a significant difference between older 1GR-FE's and newer Dual VVTi ones in terms of the Cylinder block, nor any difference from say '03-'09 blocks. I think the main issue was a poor cylinder head gasket design that was updated in later models.

 

[DC runner]

Sure. Making a stronger gasket or redesigning it can help stop the problem; but it doesn't change the reality that failures occurred along a specific path. The high degree of commonality along the failures means that in that particular area of the block you had a higher than anticipated temperature.

All this is to say; making the gasket stronger in that area may well have stopped the issue but ti doesn't negate what I said. That cylinder is getting hotter or having a higher thermal variance.

This is exactly what killed so many 3.0's in the 90's. That issue was much worse and happened much sooner. 40k miles and engines were popping.

 

[Atlanta_man]

So (excess, localized, uneven, whatever) heat is the only possible variable that causes this issue ?

 

[KidVermicious]

This is exactly what killed so many 3.0's in the 90's. That issue was much worse and happened much sooner. 40k miles and engines were popping.

My understanding is that early 3VZE motors were dropping like flies in the 90s due to bad head bolt torque numbers off the assembly line. That's what the recall was about - later 3VZEs didn't have this problem and weren't subject to the recall.

3VZE motors die now because the head gasket gets cooked by the exhaust crossover, but it takes a lot of years/miles to get there, and I've been told it's due to the actual gasket they used being inferior to the asbestos gasket the engineers originally wanted to use.

Neither of those has anything to do with the block or what it's made of.

 

[Greydog]

I was googling around for info on the 1Gr-Fe motor and I found a website that indicate this motor had a diagonal cooling port drilled into to the block in between the cylinders to reduce hot spots.

Prior Toyota V6 motors apparently did not have this feature.

I believe the gasket failures are related to this cooling port which transfers coolant into the cylinder, vs from other cooling passages around the culinder.

So perhaps the redesigned gasket addresses this unintentional weak point due to the new block cooling design?

 

[DC runner]

My understanding is that early 3VZE motors were dropping like flies in the 90s due to bad head bolt torque numbers off the assembly line. That's what the recall was about - later 3VZEs didn't have this problem and weren't subject to the recall.

3VZE motors die now because the head gasket gets cooked by the exhaust crossover, but it takes a lot of years/miles to get there, and I've been told it's due to the actual gasket they used being inferior to the asbestos gasket the engineers originally wanted to use.

Neither of those has anything to do with the block or what it's made of.

I owned 2 of the 2nd generation 4runners. A 1990, and a 1992. All years had issues, even after they applied the re-design and as far as I can remember, it was never to do with head bolts and was always surrounding the head gasket failing at one particular cylinder due to heating issues.

I clearly remember speaking with a Toyota tech some years ago as mine went in for the recall and talking specifically about heating the the gasket material. The use of aluminum heads with an iron block was part of the problem as the two materials expand under heat differently. This was years ago, but this sticks in my mind as the issue.

 

[KidVermicious]

I owned 2 of the 2nd generation 4runners. A 1990, and a 1992. All years had issues, even after they applied the re-design and as far as I can remember, it was never to do with head bolts and was always surrounding the head gasket failing at one particular cylinder due to heating issues.

I clearly remember speaking with a Toyota tech some years ago as mine went in for the recall and talking specifically about heating the the gasket material. The use of aluminum heads with an iron block was part of the problem as the two materials expand under heat differently. This was years ago, but this sticks in my mind as the issue.

That tech you spoke to was blowing smoke up your butt . Here's one reference to the bad head bolt torque: IH8MUD Forum - View Single Post - 3vze head studs?. A little googling will find you more. That was the original trouble, and the trigger for the recall. The trouble you're talking about is the the second issue I referred to - the crossover is too close to the head at cylinder 6 for the non-asbestos gasket to tolerate for long. So that's where they fail, and why they're so much more likely to fail at the slightest sign of overheating.

There's oodles of motors out there with aluminum heads on cast iron blocks, including the 20r/22r/22re, that was old tech by the time they designed the 3VZE. Toyota already knew all about how to make an aluminum head work on a cast iron block, they'd been doing it since '75 - to think that they suddenly forgot to calculate the thermal expansion differences is silly.