Lost Compression today !

[dadysev]

So frustrating! I bought this 2001 3.0 with 280,000 km on it because i have so much faith in that motor! My old e46 had 500,000 km before i sold it and it was still purring.
Long story short i'm heading out on a 7 hour journey with the family and half hour in I feel the truck jerking so I figured ok it must be a coil, as I've changed the plugs recently. had a few spares so pulled over and found the non responsive one and swapped it out. No change, cylinder 3 is not being nice!
So I drive it home only to find when I do a compression test I'm getting about 5 pounds on that cylinder! Not happy!
I've seen a few vids talking about the rings getting stuck with carbon deposits from lack of oil changes, freezing cold days ( which it was -25 C), etc. I had all those symptoms!
When I recently changed the rocker cover gasket I was not happy with the sludge ad colour in the head. I also looked for any broken springs, bent or cracked valves, ( difficult to see) and there is zero noise. Engine still sounds the same.
Anyways I poured about 2 ounces of injector, intake, cleaner in the cylinder to soak until I'm back in a few days. I really hope this helps as I'm not in the mood for any valve work.
Any suggestions? I would really appreciate it.
Thanks and Seasons Greetings!

[Fifty150hs]

Originally Posted by dadysev

So frustrating! I bought this 2001 3.0 with 280,000 km on it because i have so much faith in that motor! My old e46 had 500,000 km before i sold it and it was still purring.
Long story short i'm heading out on a 7 hour journey with the family and half hour in I feel the truck jerking so I figured ok it must be a coil, as I've changed the plugs recently. had a few spares so pulled over and found the non responsive one and swapped it out. No change, cylinder 3 is not being nice!
So I drive it home only to find when I do a compression test I'm getting about 5 pounds on that cylinder! Not happy!
I've seen a few vids talking about the rings getting stuck with carbon deposits from lack of oil changes, freezing cold days ( which it was -25 C), etc. I had all those symptoms!
When I recently changed the rocker cover gasket I was not happy with the sludge ad colour in the head. I also looked for any broken springs, bent or cracked valves, ( difficult to see) and there is zero noise. Engine still sounds the same.
Anyways I poured about 2 ounces of injector, intake, cleaner in the cylinder to soak until I'm back in a few days. I really hope this helps as I'm not in the mood for any valve work.
Any suggestions? I would really appreciate it.
Thanks and Seasons Greetings!

Burnt valve maybe? Done a leak down test?

[CapeX5]

That low of compression is not a simple fix. You will need to do some serious diagnosis. But, I would prepare yourself for a major tear down. Sucky time of year to do it, but it's coming. Accept the inevitable

[dadysev]

Originally Posted by CapeX5

That low of compression is not a simple fix. You will need to do some serious diagnosis. But, I would prepare yourself for a major tear down. Sucky time of year to do it, but it's coming. Accept the inevitable

Thats what i'm afraid of! Don't mind doing the head or gasket, just don't want to have to do the lower section!

i' have a heated garage so I'm ok no matter what temp.

[dadysev]

Originally Posted by Fifty150hs

Burnt valve maybe? Done a leak down test?

Well just did the leak down test and its coming from the exhaust side. i was hoping for a broken spring or something that doesn't require the head coming off, but i'm guessing, burnt valve like you said, or carbon stuck on the valve.
This is frustrating!! looks like i have a fun filled weekend ahead!

[scourtaud23]

Look on the bright side, there's only one head on a 3.0... And this is kind of a simple fix, a bit of teardown but pretty straightforward and way easier than opening the bottom end for piston rings.

I envy your heated garage right now.

[Crowz]

Originally Posted by dadysev

Well just did the leak down test and its coming from the exhaust side. i was hoping for a broken spring or something that doesn't require the head coming off, but i'm guessing, burnt valve like you said, or carbon stuck on the valve.
This is frustrating!! looks like i have a fun filled weekend ahead!

Use a borescope down thru the sparkplug hole and SEE what the problem is. Its usually easy to spot.

They are real cheap now. I paid like $300 or more for mine but I have seen them for $60 or so now.

[dadysev]

Originally Posted by scourtaud23

Look on the bright side, there's only one head on a 3.0... And this is kind of a simple fix, a bit of teardown but pretty straightforward and way easier than opening the bottom end for piston rings.

I envy your heated garage right now.

yeah it comes in handy. working in the garage in T shirts! lol.

[dadysev]

Originally Posted by Crowz

Use a borescope down thru the sparkplug hole and SEE what the problem is. Its usually easy to spot.

They are real cheap now. I paid like $300 or more for mine but I have seen them for $60 or so now.

Yeah Borrowing one from a friend of mine this friday before the tear down on Saturday. i will be pissed if its a piece of carbon preventing a valve from closing. that would suck!

[Crowz]

Originally Posted by dadysev

Yeah Borrowing one from a friend of mine this friday before the tear down on Saturday. i will be pissed if its a piece of carbon preventing a valve from closing. that would suck!

I wouldn't if it didn't bend or damage the valve that's fixable without even removing the head.