2000 XC70T AWD BiG Money Burnt; No Resolution oil sludge, short trips

[E Showell]

Low compression in a single cylinder, together with a misfire code (get the codes read) is a fairly reliable diagnostic for a burned exhaust valve. Usually on cylinder 2 or 3. If that is indeed what you have, then you are looking at two possible options if you want to keep the car: 1) a cylinder head overhaul, 2) replacing engine with a known good (guaranteed) used unit. The cylinder head work is about 15 hours labor and figure another $500 in parts/machining. The replacement engine route is about 18 hours labor and say $1000 for a lower mileage unit with guarantee from a place like Erie Vovo. If you are doing the work yourself, it is obviously cheaper, but it does not sound like you are doing the work. So if you budget $2,500 for the job, you won't be too far off.

[sleddriver]

Not sure if 105 was even avail. at the time. If so, I wasn't aware of it. Thus, I went with what I knew: 109.

[jamadams]

Service the CC vent system, completely.
Remove the engine oil sump and clean.
Remove the oil pickup tube and clean.

the sludge is too thick/hard to be removed with a flush.

[bronco]

Sludge is a funny thing ! Old oil can cause strange problems. I once bought an F250 plow truck that was a garage find , it supposedly had a rebuilt engine but hadn't started in a decade . I got a good deal on it even if it never ran is what I figured , for 700 bucks it had a clean straight body and a functional fisher snowplow.

The engine would not crank or turn over with a breaker bar . I pulled all the plugs and filled the cylinders with PB blast . 6 weeks later it turned over and ran . I did a little carb and ignition work and it seemed ok if very noisy. I plowed my yard with it one winter then decided to figure out what the noise was. Compression was bad and it had sat a long time so I decided to pull valve covers and intake manifold. These cleveland style engines originally came with stainless steel bathtub intake manifold gaskets and I could see that that was not present. With paper intake gaskets they have a lot of trouble sealing the intake port in the head to the manifold , they get vacuum leaks under the intake , draw in oil from under the intake etc.

Everything looked fine and I was stumped but somehow I noticed that none of the pushrods would spin. These engines had hydraulic lifters and any closed valve should have a pushrod you can spin between your fingers but none of them would.

Turns out every single lifter was acting like a solid lifter because the oil inside had hardened up and they could not bleed down.

I took each lifter apart one at a time cleaned it put fresh oil in and tested it to make sure it moved. It was like night and day different when I restarted it . Its easily the most powerful , well engineered 400 cu inch ford engine I have ever seen.

The truck was crushed by a pine tree but I took the engine and swapped it into my bronco as it was. 13 years later its still in my bronco still running the same way!

[bronco]

I should have said acting as a solid lifter with essentially zero valve lash