I found this great article that explains that liners can't slip on the newer engines because they are held in place. Instead the block cracks most likely due to the head bolt's stress on the block. Here is the article: http://robisonservice.blogspot.com/2...-failures.html

 

Interesting read. So what engines are affected by this? Just the 4.6?

 

I read that same article earlier this year - good read (thanks for posting LR Scott).

It does seem to also confirm that worn out tooling was used toward the end of the P38 era.

Wilson it would apply to the 4.6 and 4.0.

 

So indulge me guys as I have a limited knowledge of this. First if I were to replace my head gaskets it is my understanding that this would correct the issue with the liners? Being that I have a 2002 with 58,000 miles when should a repair like this take place? Or are the liners not a issue with 2002 model years as it is a newer P38?

Your insight is much appreciated! The head gaskets and liners have always been a concern since buying my Rover but since it has been running perfectly I was never concerned. I don’t even know what they symptoms would be if their was a problem!

 

According to the article, they can't slip, they are held in place. Its the head bolts that cause the block to crack, usually invading the cylinder just outside the liner. Since the liner isn't sealed in there air tight, the exhaust gases leak into the coolant and cause the engine to severely overheat. Why it cracks at the head bolt, idk.... In the end, newly installed top hat liners will repair the problem, even if it is a block crack, the new liner design keeps it sealed.. The repair runs about $4k and basically involves rebuilding the engine.

IF you had this problem GSD, your rover would overheat very quickly. Within a couple minutes. The failure is usually sudden and without warning. If a rover is overheating every now and again (getting a little warm at a stop or under load) it would indicate something else. The best way to prevent block cracks and head gaskets failures is to NEVER let your rover get even slightly too warm. And when replacing head gaskets, make sure you use new bolts and follow the manual's instructions on the torque settings. I am willing to bet the problems are just the block being fragile and since the gaskets corrode faster on BOSCH models, the mechanics who are unfamiliar with the engine take a cavalier approach to the job and over tighten the bolts and over stress the block. It could also be due to other factors too which are debateable. Some argue that the blocks on the newer rovers did not have the bolt holes drilled and tapped properly, leaving that part of the block weak... Truth of the matter is, we may never know for sure. There is a permanent repair, but it does cost a ton.

 

So is this only later p38s or would my 1996 4.0 be affected?

 

Wilson technically it would be any 4.0 or 4.6 and possibly earlier versions with the 3.9 liter. It's the same Buick design they have used for ages. It's nothing to freak out about, there is essentially nothing to do about it unless/until you have a problem. Just make sure you don't overheat. Check your cooling system components regularly, change your coolant per the schedule, check your plugs for white fouling annually at least.

I believe that over torquing the head bolt is a large part of the equation like LRScott indicates, as well as perhaps too narrow of a tolerance between the bolt hole and cylinder wall (design issue), then add heat cycling to the deal and there could be the problem - the block is aluminum, the liner is steel. Remember these engines started out as 3.5 liter and have been bored out over the years = less metal to fight thermal expansion.

Seems to me in the linked article he is talking about later model engines from approx 1999-2004 that have less likelyhood of liner movement. The earlier ones can and do slip liners but also are cited as having been produced with tooling that was less worn.

It's all confusing and a bit of conjecture too.


gsd - changing your head gasket at 58,000 miles seems premature to me. I'm all for preventive maintenance but I wouldn't go that route until around 100k miles in my opinion. A new head gasket isn't necessarily going to prevent engine overheating and failure, there are other pieces of the puzzle too.

 

Thanks so much for the information guys! She is running like a champ, and hopefully will for years to come! Never seen the temp gauge climb past normal. But I will keep a close eye on it.