Its possible that the valve guides are worn, however I dont think its the cause of the leaky head gasket that you mention in your first posting. I dont know enough about valve guides, but I am guessing if you are running oil changes from 10-16k miles you might have some valve train damage. You mind as well have him check the timing chain, tensioner and guides while he is in there.

mea culpa
 

I took your abbreviation and my ignorance as FSS= Full Service Synthetic

I'm running synthetic and typically change every 10K, 16K was my worst offense. I typically drive ~1K/week.

outer leak
 

I've read in other posts about a coolant leak from the rear of the engine passenger side "common" on my engine. Ther eis no mixing of coolant and oil which is good and I do think i could drive for another 10-20K miles in present condition. However rather than push it off and chance an overheat possibly warping the head I wouuld do the right thing and have them change the gasket. Everything else at the shop tested fine so I assume the valve guides are not in "spec" anymore. They didn't give me the size. I will ask though.

no numbers
 

The shop didn't give a spec to the mechanic, he/she just said they're bad and should be replaced. I'll get a number next time they speak, but it didn't sound like it would be advisable to re-use them

Phil couldn't get them either

Without a proper specification and precise measuring tools..........how could the mechanic make an opinion as to whether they need replacement..........think he can do it by "gut feel"???:rolleyes:

Perhaps I wasn't clear
 

The mechanic (M1) doing all the engine work didn't know the number as the head was shipped to another place that exclusively rebuilds heads(M2). M2 didn't give M1 the specs and I'm only in touch with M1. M1 said he would find out the numbers next time he speaks with M2.

Sorry.

Why?