Why I want to replace it? Oil loss 1qt/700 miles, no visible leaks, PCV mod and valve covers done already, engine runs fine, no blue smoke.
How long will the job take?
Should I put in new fuel injectors just because of their age and mileage and since I am at it anyway? (I have no codes, fuel economy is not concerning, 135k miles)
Thanks

 

3 or 4 hours I think, the gasket is not hard it is all the stuff you have to remove to get at it. Fuel injectors are pretty easy to after.
Have some new wiring loom cover, mine was pretty rotten under there.
Presoak the AC bolts they can be really tight, make a terrible noise for the 1st few seconds

 

Injectors almost never fail, and are easy to get to if they do later. Valley gaskets due leak sometimes, bought a truck leaking 2 quarts every 6 miles due to blown intake gasket but it was obvious where the leak was. Personally I never get them down that far (lower intake off) and don't change the HG - you are only valve covers, exhaust manifolds, and headbolts away at that point because you have taken the accessory brackets loose.

Doubt the engine is drinking it with no blue smoke. Did you pull the plugs? Could just be valve seals. Easy to replace with only valve cover and rocker removal.

 

Documents from P.O. show, that valve stem seals were replaced 4 years or 30k miles ago when the HGs were done. I assume they are not cause of the oil loss.

 

I just learned, the valley gasket is part of the head gasket job. Either they did a bad job or there must be another reason for the oil loss.

 

It is possible it is not sealed correctly. Test it by putting a latex glove over the oil fill tube with the engine running, tightly seal to the edge. If it sucks in slightly, it is sealed, if not you either have a pcv problem or a gasket problem. Pull the hose off the valve cover and make sure you have suction at the hose.

 

I have vacuum at the breather hose, my gauge shows 18 in. Also, I blocked the breathers hoses and when I run the engine at idle there is no vacuum in the crankcase. I think this rules out an internal leak from the crankcase to the intake. I noticed there is an oil film on the right valve cover. The oil filler neck as well as the oil cap did not seal properly. The O-rings were like hard plastic and I installed new ones. I doubt that a leaking oil filler neck causes an oil loss of 1qt every 700 miles, but let's see how that changes oil consumption. For now I am hesitant to replace the valley gasket.