Yes, I've replaced my engine mounts. They don't last forever... are difficult to see the problem.... and there are probably many folks driving around with cracked ones.

The engine that Bob Wilson (87_montero) brought to me also had cracked mounts. They usually separate in the joint between the steel pad and the rubber, although some split the rubber pad.

IMO, any 15 year old 3.0L with over 125K miles - and most particularly one without heat shields on the mounts and/or exhaust manifolds - is a candidate for new mounts because they are fairly close to the exhaust manifolds.... heat is the worst thing for the rubber and/or the glue.

Frank