how common are LIM gasket leaks on Series II?

[Billha]

How common are LIM gasket leaks on a Series II? If and when the gaskets fail, at how many miles?

Also, are S/C gasket leaks a typical problem on the supercharged Series II?

Thanks.

[rm25x]

Every series II NA I have ever seen will need the upper intake replaced, and while your at it just do the lower beause it won't be far behind. My dad's '99 Lesabre has had 2 intakes on it now (bought at 60k miles, now has 260+)
He just bought a 02 Lesabre with 94k, and I bought my 01 Bonnie with 116k, and we ordered all the stuff to do upper and lowers on both cars. Better to be safe then sorry.

[00Beast]

It is not if the OE gaskets will fail, but when. Some have failed at 50k, some don't fail till much later. Mine were just beginning to fail when I replaced them at 142k.

The S/C gasket isn't very common to leak unless someone has removed the S/C and didn't replace it, or didn't remove all the old gasket.

[Billha]

I was hoping that the LIM gasket only failed on some engines :(
Where's the best place to buy the aluminum LIM gaskets and the S/C gasket?

[00Beast]

Any auto-parts store. Get the Fel-Pro Aluminum gaskets and a Fel-Pro S/C gasket.

[Billha]

When the LIM gaskets fail, do they typically fail slowly, over several months or longer?

I typically check the coolant level regularly. Would I be likely to notice the coolant level drop well in advance of any permanent damage being done to the engine?

[00Beast]

It's a guessing game. Some fail slowly, others fail catastrophically. Your best bet is to do them soon, and not worry period.