On the one hand I read the engines go hundreds of thousands of miles...

[robgagnon]

And on the other hand I keep reading about blown head gaskets.

Is there some inherent weakness in the head gasket design? Are all these head gasket issues happening due to
overheating?

Thanks - Rob

[timsrv]

It's not that these engines are any more prone to head gasket failure (as compared to other cast iron blocks with aluminum heads). The real problem is the van is prone to overheating & that's what leads to head gasket failure. The reason they are prone is placement of the radiator & the barely adequate air circulation through it. When everything is functioning correctly there's no issue. All it takes is a fan clutch failure, debris on the radiator, internal radiator scale/blockage, damaged or missing fan shroud, etc. If you allow one or more of these things to occur & go unchecked you're headed for disaster. If you stay on top of things and keep engine temp under control then you should be fine.

Most vehicles can tolerate the faults listed above because the radiators are mounted up front and get good ventilation. Not true for vans...........therefore van owners need to be more aware of these things. Tim

PS: We've had this discussion here at least 2 or 3 times before. To find them use the search feature. Here's a good one: http://www.toyotavantech.com/forum/showthread.php?765-getting-to-the-bottom-of-head-gasket-failure