We went from a 05 MCS to an 09 this month. So now we have the turbo. We also have a Passat with Turbo and there are reports about sludge resulting in the passats, related to the turbo cooking the oil. Is there any concern about the turbos in the MINIs causing any sludge? Passat owners have recommended using only synth oil (we do anyway) and letting the engine idle for a couple of minutes after driving a fair distance to allow the turbo to cool before shutting off the motor.

 

MINI S turbo has what is basically a "turbo timer" ...term for a device one could add on aftermarket that allowed oil (the coolant for a turbo) to run on after engine shut down (and even more basic version was that even if you 'turned' the engine off the timer would keep engine running X number of minutes so as to allow oil to continue running thru turbo)...without one of these if you ran the turbo'd engine reasonably hard and did a cold shut down oil residing IN the turbo would cook. But MINI S (07-09) comes with such a system OEM (after you shut down the engine you will here a whiring sound and if you are near the turbo you will also hear oil running thru the oil feed line to the turbo)... but with that said I suggest if you run your car thru the gears and really get that turbo going that as you are arriving your destination let the engine cool down a bit by keeping revs down then just shut down and let the turbo timer do its work. And to the question of oil cooking (really is not sludge)...yes it can happen if you are one of those who run the sn*t out of your engine then just shut down... Yes, with syn oil that reduces possibility of oil cooking quite a bit... pre syn oil and pre turbo timer turbos did not have a very good life expectancy.
Michael

 

This was another suggestion for the Passats, as VW did not include this stock. Good to know that BMW/Mini did.

 

Do you think 1 minute of parallel parking would be sufficent time? I push my car on the commutte home, but drive slowly through a neighbor hood for about 10 minutes, so I'm sure I'm fine. But, my guess is that 1 minute of parallel parking would probably be sufficent to cycle oil through the turbo. What do you think?

 

Your Fine, dont worry, the engine ECU system will take care of it, after shutdown.

 

Well, low revs through the neighborhood should have cooled the turbo down fine to make it safe to park. Depending if it's an auto or a manual, the minute of parallel parking could be actually raising the temps again. I used to drive an auto diesel truck w/a pyrometer. If I idled in gear, exhaust temps (pre turbo) would quickly reach 350f with a warm engine, low speed moving would get me up in the 450's or so, enough to cook most oils. If it was coasting or out of gear, temps would fall quite quickly.

Disclamer: Exhaust gas temperatures on a diesel are usually much higher, and are much more of a concern than they would be in gasoline engines. The engine in question would hit 1200f at full throttle. I do not think that the temps in our engines at low speed are as high as the ones above. Perhaps someone who has a pyrometer on their S will chime in with some temps.

 

That's interesting you say that exhaust gas temps are higher in diesels and lower in gas engines, my experience is exactly the opposite. Many aircraft gas engines have EGT probes (we use them to set the fuel mixtures at altitude) and 1350-1400 degrees F is common during high power operations. The Lycoming I commonly fly gets leaned to 1200 degrees at 65% power. Also, when I worked in the electrical trade, you could use the exhaust of a gas engine to heat PVC piping enough to bend it, while a diesel exhaust wasn't hot enough. This could be a bit of an "apples to oranges" comparison, since I don't have any experience with big diesels.

Also, for aviation turbos the usual cooling period is 2 minutes at idle, so several minutes of suburban driving should be plenty to cool the Mini's turbo.

 

One of the problems with VW / Audi 1.8 turbos was they were run with non-synthetic oil. That, coupled with owners not doing oil changes on schedule was a recipe for disaster. VW and Audi now use synthetic oil for their cars. I have had five 1.8 turbo cars and zero problems with them.

 

Well, was that diesel turbocharged and working hard at the time? Like I said, in neutral the temps would drop quickly. The temps would sit at around 170 degrees at idle in neutral. If you put your foot on the brake and sat there with it in gear, it would sit at 350-400. I know that my EGT registered those temps at full throttle, and it's common for other modified Cummins 5.9's like the one I had to push 1300 with more aggressive modifications. That temperature is important because the iron in the turbo housing becomes workable and soft at about 100 degrees above those temps, (and is doing some weird things magnetically at those temps, upon re-reading the wiki article). The turbo glowed quite red after towing something down the freeway. It did only have a piggyback module (advanced injection timing and volume, with a boost fooler) and a smaller wastegate elbow, the injectors had not been upgraded, so it might have been a little lean.

My point of reference on a gasser's temps is a friend's DSM turbo 4-banger. He said that he was running rich in order to control EGT temps, but he had never seen anything over 1000. But, after further thought, I did remember another friend with a similar engine who kept leaning out his mix in the interest of fuel efficiency, and he recently melted a piston, so obviously crazy temps are possible with enough control. I'm sure being able to manually lean out the mix at a fixed throttle position would allow you to safely lean out to 1200 at 65% throttle, and it must be nice on fuel efficiency. I'd imagine a similar setup would be a nightmare on a car, though. Do you know why they are using a pyrometer to judge fuel mixture and not a wideband 02 sensor?

 

Isn't it the electric water pump that keeps running after you shut off the engine? I wasn't aware that the oil pump was electric

 

I did further research...>>>
So yes... the whirring noise and fluid in the pipe noise is indeed water coolant... good catch. It is interesting that the BW turbo appears to use both oil and water coolants

 

I'm late to the party, but I don't know of any MFR who isn't using water cooled turbos nowadays - Chrysler started using thos mid 80's...........

As such, the only way you can get coking in the turbo housing is to come off the track and immediately park - in normal city or hiway driving it's just not possible. If the Passats are getting sludged it's probably from short hop driving, where the engine doesn't get warm enough to burn off moisture, not hard driving. Switching to a synth oil should fix it easily, otherwise longer drives and regular oil changes are all that's needed, you do not need to idle your engine in normal driving - it wastes gas and simply isn't necessary.

 

It was non-turbo 1.9 liter car diesel. I've always thought it was the diesel's better thermal efficiency that resulted in a cooler exhaust, but I'll research this.

I'm a little bit familiar with the Cummins diesel, nice engine. All internal combustion engines create higher exhaust gas temperatures when they're run harder. I'm not surprised a tricked out engine can generate those numbers. One thing to keep in mind, the temperature of the turbo is a function of the wastegate setting, not the power output of the engine. Open the wastegate and the exhaust bypasses the turbo and it will cool down.

Yep. Based on the theory that an optimum fuel mixture generates the most heat, an EGT sensor gives the same mixture information as an O2 sensor. Also, all systems that get installed into airplanes have to be approved by the Federal Aviation Admin, and since airplane piston engines are one tenth of one percent of the total engine market, there's little motivation on the part of engine manufacturers to develop an aviation O2 sensor. In addition, most aircraft engines are purely mechanical with no ECU to interpret an O2 sensor's data. That's changing, but given the primary goal of an aircraft engine is "not to fail", that change will be slow.

Oops, my apologies for the topic drift. Didn't mean to hijack the thread.

 

That's good to hear. I've been using full syn oil since day 1 with K&N filters and change @ 5K mi. I do a fair amount of short drives (0.7 mi to work), so MiniDaves comments are good to hear, too.

 

the most important part is high quality synthetic oil, red line takes the most heat due to its ester base stocks, expensive but better, amsoil is also very good, i have 174,500 on my 01 turbo jetta, its chipped and rodded to 275 tq and 255 hp, no problems, with my free 2 yr service the stealer refused to install my amsoil, so as soon as i drove home i dumped the castrol reg out, a little later they spec synthetic, be aware some oils labeled synthetic like castrol syntec is not real, ony due to change of laws, like big pharma does it can be called synthetic, indy coop keep after that timing belt on the passat

 

Wonder why my '09 MCSa has an embossed notice next to the dipstick that says, "MINI recommends using Castrol?" I guess they just like doing engine repairs under warranty?

P.S. Thanks for the commas...they help...but what about a few periods and capital letters?

 

because thats what castrol pays them to do, like most big business its ALL about the MONEY, once the warranty is gone its more profits on repairs,
castrol isnt a bad oil but IMHO theres better out there

 

Castrol Syntec 0W-30 which is made in Germany is a superior oil and a true synthetic. This is what I use in my MCS. It meets the requirements of BMW/MINI among other manufacturers. This stuff is so good that it has it own discussion forum on "Bob is the Oil Guy": http://www.bobistheoilguy.com/forums...643#Post718643

 

Our Audrey had it's oil changed according to the service schedule. They changed it once a year with regular oil, not synthetic. Audi paid for all the maintenance on our car. I asked for synthetic & they told me OK, but I would have to pay for it. It was a lease car so I didn't much care. Long story short the engine sludged up. It was fixed under warranty & was never right after that. After the lease the Audrey became Audi's problem.

PS: There was more to the engine sludging than just the use of non-synthetic oil. There were major changes done to the crankcase ventilation system as part of our Audrey's repair.

 

+1 - most sludge issues are caused by poor engine design. There's a reason why it seems to plague certain models and engines, and not others. A well designed engine that sees regular oil changes with a high quality synthetic oil will not form sludge deposits.

 

On of the Audis was a 2000 A4. We ran that one over 100K without an issue. I did the oil changes every 5000 miles and when it went to Audi for the free service I hand carried in 0-40w Mobile One. I am sure there was an engine design problem (Hell, it only held 3.8 qts of oil with a filter change) but with regular oil changes with Mobile One I was able to avoid any major problems.

 

Our Audi was a lease car. We played by their rules & had it serviced by them according to their requirements. We ended up with a engine full of sludge.

Now had we been driving an Audi that we bought you can bet the services would have included synthetic oil on a much more frequent change schedule.

Good on ya for doing the right thing for your car. Shame on Audi for trying to save money & having their engines sludge up.

 

I had a 1988 Toyota pickup, V6. The 3.0 liter V6 were recalled by Toyota for sludge build up. I never had mine serviced at the dealer as I did all the maintenance on it. At 130,000 miles I got a new engine from Toyota.

It's all about how well the manufacturer stands behind it's product when things go bad.

 

Yes Toyota finally did the right thing. They were getting a lot of bad press & that helped them do the right thing.

Audi extended the engine warranty to 100K IIRC. I'm so glad ours was a lease & went back to them.