i think i found something about the L36 UIM failure .after removing mine dated 1997 it was like new so that 10 years .yesterday i did i remove the one on tjblackbonne black 1995 bonneville but that engine is a 2000 whit the stock upper and it look fine.So i think the upper intake falure is not happening in the nothern us state or canada .After asking about this in montreal to a shop they say they never see a intake melt in the egr (saw one only but the cat was plugged ) .Also in platsburgs ny at advance and auto zone they don't have any elbow in stock they don't know what where talking about .so maybe that why GM as always denied the fact of the upper failure .will see also the upper on tj white car that a orignal 1995 L36.I will post pict of my upper later.So say here about youre upper failure and let see if what im saying make sense

No offense, but can you take a look at this topic, please?

http://www.bonnevilleclub.com/forum/...ic.php?t=73691

Maybe less often up here, but it does happen. At least in Toronto, which is admittedly warmer than Montreal.
When I did mine in February, it was just starting to go. YOu could just see the distortion around the stovepipe area. Oddly enough, the dealer had replaced the UIM gaskets a couple of years before, but had not done the UIM itself. Go figure.
So, while it might not be as common as in the US, it is happening up here too.

Don..they still happen. It might look good, if you poke at it.. you may find it'* weaker than it looks.

yes vital im sorry my english is not that good but im a french canadien im working on it.also one thing that is sure all the lower gasket where bad almost leaking