2005 XC90 P0304 and 305

Post by **SuperHerman** » 14 Jan 2020, 22:04

Quick and dirty test is to put a cap full of oil in #4 and #5 and see if you can exclude the valves. If it works, then put some Seafoam in the pistons a few times over the course of a few days and see if it frees up the rings. Don't put more than 1/2 a treatment total so you don't ruin your oil and you can keep working on it by driving.

If it is the valves, I would source an engine and see what you think of the price and work. Once you are comfortable keeping the car, I would pull the head and see what you find. Personally in my garage I would rather pull a head than an engine. Some would rather pull the engine. Price out a head gasket kit and figure $100-$400 to have your head rebuilt. Here I can get the head machined for $100 and lap the valves and service the head while watching TV or listening to the radio. Identify any bad valves and replace, used valves are an option. If the seats are bad, I would farm that out. By pulling the head first, you are only out your time and you will have a fresh top end with all new seals for less than a used engine from a wrecker.

You could also re-ring the pistons by dropping the pan - just do #4 and #5. On my old S80, 2.9 na, I just did one piston ring set and had no issues. Pulling the head is not too bad and will answer many questions if the solvent treatment is ineffective. Once it is off you can decide the course you want to take, being only out time.

h20ham · Post by **h20ham** » 23 Jan 2020, 12:37

All I can get “locally” within 400 miles. Is cores.
Maybe the timing belt broke (on this core with 200k miles), and I would just need to change a valve, but then. What else. As always.
Or purchase a sleeve kit, $1000. And $800 in machine costs. Well then.

I guess I better have some cam followers ready. So that’s the next question. I suppose buying a core at $300 is better than finding out I need 4 followers (about the same price). And or hopefully the block is better, if this one is damaged.

Tough, as there is no great answer.

Post by **SuperHerman** » 23 Jan 2020, 18:53

I think you have concluded - pull the head and look and have a back up complete engine ready to purchase.

If you pull the head and the cylinder walls are clean you can pull the pistons and clean the rings.

Did you try the cap full of oil test or a leakdown?

Maybe try some of this GM Fluid 88861803 Upper Engine and Fuel Injector Cleaner and see if you can free things up.

Post by **abscate** » 24 Jan 2020, 05:07

Bumped back to XC90 forum with breadcrumbs

h20ham · Post by **h20ham** » 24 Jan 2020, 21:05

Happy Chinese. Moon
Tried the leak down test. And #4 leaks out #3&1. #3 leaks out #1. 5 leaks out 1 &3 much less
All out the spark plug holes
Borescope shows no damage on cylinder walls
No cylinders leak out exhaust, intake, or dip stick oil cap.
Guess a head gasket job is in order, unfortunately. All I can get is the Fel (less than pro) pro. Ah well. It’s a complete kit.
Any suggestions please

Kind Regards

Post by **abscate** » 25 Jan 2020, 05:45

I’m sure you can get an OEM head gasket, although FelPro was respected last I checked ?

Post by **RickHaleParker** » 26 Jan 2020, 00:32

h20ham wrote: ↑24 Jan 2020, 21:05 Guess a head gasket job is in order, unfortunately. All I can get is the Fel (less than pro) pro. Ah well. It’s a complete kit.
Any suggestions please

Fel-Pro is top shelf stuff. Shocks me that you would think the brand is anything other then top shelf.

h20ham · Post by **h20ham** » 26 Jan 2020, 09:55

Judging only by oem whom uses different metal (i dont have either to compare) on pictures on the net, for cylinder top sealing surface.
If the head gasket is not one of the more important pieces.
Hoping for someone who has experience with these heads and gaskets.

Sometimes oem is not better, i doubt in this case it is

h20ham · Post by **h20ham** » 26 Jan 2020, 10:01

Also, fel pro is Chinese metal
Oem is more likely European

XC90Dave · Post by **XC90Dave** » 26 Jan 2020, 11:33

An old school test is to insert the compression tester hose into the cylinder head @ the cylinder having issues and connect your compressor air hose to the gauge hose. The motor can be turned (by hand) and when on the compression stroke (valves are all closed) you will hear the air leaking to either another cylinder, to the exhaust or to the intake. Simple method to get a mental picture of whats happening inside. Hope it helps.

2005 XC90 P0304 and 305

Re: P0304 and 305