This is a big issue for people with the original LR-Buick aluminum V8 engine - all the US market Defenders and Range Rovers to 2002 and Discovery I and II models through 2004.
The engines overheated and failed either right after the head gasket job, or within a few months. At first I thought the failures were comebacks - errors of workmanship. But I soon realized the problem was not the workmanship - it was the motors themselves. They were failing internally, in seemingly invisible ways.
Join me now as we look closely at a seemingly simple head gasket failure, and find there is much more to the story . . .
This 2001 truck came into Robison Service a few days ago (early 2014) with a noise complaint. Exhaust gases were blowing out between the head and the block. It seemed like a classic case of fire ring failure in the head gasket. In years past, I'd have been right on it with new head gaskets and a cleaned up heads. Today, not so quick . . . As it happens, our caution turned out to be well founded.
Here are both heads off the motor. As clearly shown, only one has a blowout (second cylinder from the left, upper head) So far, it looks like a blown gasket.
The orange is sedimented Dex-cool. Sedimentation is a known issue with Dex cool and it's particularly visible here. It looks very different from freshly spilled coolant, like you get from teardown. Scroll down the page four more images and you'll see freshly spilled coolant in a head bolt hole. There's no mistaking the difference.
There are some motors where the head bolt holes go into the coolant galleries. This isn't one of them. These holes should be dry. The fact that they are not suggests a crack or leak somewhere.
The blowout has damaged the head slightly but it's nothing we can't fix with a weld and resurfacing before the valve job. Right now, that is the least of our worries.
Here's a photo of a stripped engine block, after we cut it in half and circled the crack that made it fail. The coolant passages are clearly visible
As a footnote to this story, when told about these issues, the owner of the truck told me he'd been adding coolant for a while for a period of months. Now we know where it was going. The coolant was getting burned in the cylinders as it leaked from the cracks behind the liners. The fire ring blew out because the block cracks caused the head bolts to lose their clamping force. We have an explanation for the whole thing, disagreeable as it may be to the one who has to pay the bill. Still, I contend it's better to know the bad news up front than to discover it after a $3,000 valve job and head repair goes bad.