OMG What's with the Sludge/Carbon Buildup on the I5Turbo?

cfoss · Post by **cfoss** » 09 Dec 2021, 21:01

Hey all.

I had a 2001 XC70 that died on the way to the interior of BC. Lost oil pressure in the middle of nowhere and had to limp it in-car was toast, and many miles away from home so I had to let it go. After this experience I searched and found out the oil pickup tube likes to get clogged up. Pretty sure that's what did it-car had plenty of oil etc.

A couple of years later now, and my wife really missed the car, so we got another one. Pretty much the same, but a 2005, and in REALLY nice shape, and well maintained-bills to prove it.

But I was taking no chance with this one-I dropped the pan et voila! The oil pickup tube was half clogged with black hard crystally garbage. It was everywhere in the oil pan and up the edges of the block. I cleaned them out the best that I could (A product called Lestoil is killer on this stuff) and have just reassembled.

Anyone have any idea what causes this? Please don't say lack of maintenance and non synthetic oil-not buying it. This car has the bills to prove very regular changes with synthetic. Do these engines just run hot? Or is the lack of water cooling on the turbo an issue perhaps?

Chay

Post by **RickHaleParker** » 09 Dec 2021, 22:20

Carbon particles getting past the rings. It is a tiny tiny amount per cylinder each cycle but millions of 0.001s add up. Oil will suspend most of the particles until it becomes saturated but, nothing is perfect.

wch2032 · Post by **wch2032** » 10 Dec 2021, 00:54

What's interesting is that earlier this year (~15K miles ago) my car was sitting in the mechanic's lot for over a month while waiting on insurance and parts for a front end collision repair...when it was fixed I had intermittent oil pressure warning lights over 3-3.5K RPM, until it stayed on after 3 hours into a 5 hour road trip. I put some more oil in to complete the trip (no leaks and oil level was OK), and then when I returned home I had an oil change and vóile I haven't seen it since. I'm not sure if it means I need PCV or oil pan work (I think the latter since being stationary for a month is never good for any cars), but otherwise it hasn't exploded yet. I'm more diligent about running high mileage synthetics with more detergents now, and probably an oil pan drop is on the list.

Post by **abscate** » 11 Dec 2021, 05:22

cfoss wrote: ↑09 Dec 2021, 21:01 Hey all.

I had a 2001 XC70 that died on the way to the interior of BC. Lost oil pressure in the middle of nowhere and had to limp it in-car was toast, and many miles away from home so I had to let it go. After this experience I searched and found out the oil pickup tube likes to get clogged up. Pretty sure that's what did it-car had plenty of oil etc.

A couple of years later now, and my wife really missed the car, so we got another one. Pretty much the same, but a 2005, and in REALLY nice shape, and well maintained-bills to prove it.

But I was taking no chance with this one-I dropped the pan et voila! The oil pickup tube was half clogged with black hard crystally garbage. It was everywhere in the oil pan and up the edges of the block. I cleaned them out the best that I could (A product called Lestoil is killer on this stuff) and have just reassembled.

Anyone have any idea what causes this? Please don't say lack of maintenance and non synthetic oil-not buying it. This car has the bills to prove very regular changes with synthetic. Do these engines just run hot? Or is the lack of water cooling on the turbo an issue perhaps?

Chay

I would guess that someone billed for synthetic and used Dino oil to pad their margin, especially if it’s a quick oil change place, or it was a short distance use car which was never getting hot

With 7500 mile OCi and castrol synthetic I have had no sludge in my turbos over 100,000s miles

Post by **cn90** » 11 Dec 2021, 11:36

1+,

Long OCI and short trips (< 7 miles) is the culprit.

If you:
- Use synthetic
- OCI< 6K-7K
- Once every 1-2 wks, group all the trips together (grocery, soccer game for kids etc. etc.) and do them together..

...you should not have sludge.

OTOH, if sludge is already there when you bought it, then a slow gradual diet of synthetic + frequent changes such as every 3K-4K "may" or may not remove existing sludge.

SVO LOU · Post by **SVO LOU** » 11 Dec 2021, 11:46

My theory is that most people drive a turbo like a normally-aspirated one...Drive it, get to your destination, and turn the engine off instead of letting the car idle for a minute or so you don't get as much oil coking.

cfoss · Post by **cfoss** » 15 Dec 2021, 10:27

Well we shall see I guess

I run nothing but Mobil 1. I do short trips though so we will see

She’s as clean as I can make her for now

The oil pan is actually pretty easy to drop so I’ll probably do it again 100k into the future and see how we are doing. With a stereo upgrade this car will be in the family for many years to come so I want an engine failure to be out of the question.

I also had to do the angle gear collar weld trick with this sucker to restore the awd. Really looking forward to getting it on the road ahead of the winter snow here

Thanks for the advice

Chay

Post by **- Pete -** » 15 Dec 2021, 20:07

Chay, when you dropped the pan & cleaned everything, did you update the oil pickup tube?
Guessing you replaced all the various seals & o-rings, but in addition to these things there is a newer updated version that supersedes the original metal ones. The new plastic ones have a trumpet/bellmouth shape at the oil pickup end. This change in shape is largely the reason these pickup tubes don’t promote clogging of the pickup tube’s screen. Once you shut the engine off, the debris (if there is debris being sucked up against the screen) just falls to the bottom of the pan. I’m sure some of the particles become stuck in the screen but compared to the old metal style pickup tube a great reduction/improvement.

The old metal style pickup tube is shaped like a UFO/alien space ship which has a hole in the bottom of it, through which the oil is a sucked. The problem with this pickup tube/hole (in sludged engines) is that it has an inward protruding lip. The screen is sandwiched halfway between the 2 clamshells of the spaceship. Because of the design and the inward protruding lip, debris has a much harder time evacuating the area of the screen when you shut the engine off.

Here’s another thread with some pertinent information.

viewtopic.php?f=9&t=90563&hilit=Oil+pickup+tube

The easiest way to prevent/lessen sludging & crystalline buildup in your oil pan & PCV system is 1) minimizing the short heat cycles (longer run times between shutdown), 2) using good quality oil & 3) applicable/reasonable OCI’s. If you do nothing but short drives & short engine-heat cycles I’d run the car out in the country/or on the highway weekly for a period of time & probably also tighten up the OCI’s.

All 4 of my P2’s get run 4K between synthetic (Rotella T6 5-40) oil changes & seldom see short engine-heat cycles. I’ve also updated the PCV systems on all of them. I’m not trying to say my way is the only way, but it’s worked for me for a very long time. Oil is cheap & there’s nothing foolish about fastidious maintenance.

It’d probably behoove you to take a real good look at the lower PCV system as well (if you haven’t already. There are passages that run from the oil pan up the front of the block that often times become fully or partially occluded.

cfoss · Post by **cfoss** » 17 Dec 2021, 10:26

Updated oil pickup tube? Now you tell me??? LOL

Nope, didn't know one existed. Next time I guess.

The thing is, those hard deposits were so stuck on to the screen it's hard to believe they would just fall off, but maybe they weren't always so embedded in there...interesting approach to solving the issue anyway.

Thanks for the info on the PCV system-I will check it for sure.

I didn't do the orings although I probably should have, just because I was in there. When I saw them I did check them-They were pliable and not flattened off, and for sure they protruded past the surface so they will seal up well. I will do them next time though-Just wasn't aware of them being such a problem before I put the pan back on.

Chay

cfoss · Post by **cfoss** » 17 Dec 2021, 10:29

My big problem with the oil changes is:

4 cars
Motorhome
2 boats (total of 5 engines)
3 dirtbikes
3 kids and a wife

Doesn't leave a lot of time, if you know what I mean. It's a good problem to have, but still a problem none the less.

Chay