I assume its just the one because it reads 5 psi lower in compression test (145 compared to 150 on other three).

would it be cheaper on labor (obviously in parts) to just fix the one? or is this something you usually just do all four?

I got a quote for $329 labor for all four, + parts, which I don't even know exactly what I need but I have a DIY from HT bookmarked that might have the details.

thanks.

 

Well, compression really has nothing to do with valve stem seals since they are outside of the combustion chamber... Anyway, if you are going to do it, you may as well do them all. However, the seals don't typically just fail; they usually fail because the guides are getting loose. Because of this, the seal replacement will very possibly only be a temporary fix.

Ryan

 

are guides not typically replaced with the stems/seals?

and I suspected that one cylinder also because it was the only spark plug that didn't have normal wear.

 

anyone?

 

if you plan on doing it your self there are two ways of doing it.
1. your most common way is to pull the head and do it that way, this is the easier way to do it but takes more time,
2. if you have a leakdown tester then you can fill the cly with compressed air and when you take the valve spring off then the valve wont fall down into the cly. although this seems easier, the fact of the matter is that the cly head not being off dosent allow for as much room as you could wish for and this also takes a diffrent style valve spring compressor then say you would use with the head off.

as for your question, i think it depends on how the shop will take the approch cause if the head is already off then I would replace all the valve stem seals and also check for valve guide wear. and if your feelin really feeling froggy then you can mark the top of the valves with a sharpie then spin them around to check for seating.