1999 BMW 328i...Is it a known Sludger?

[JAG]

My mother owns this car and takes mostly short trips. Whenever I check the oil fill cap area, there are water drops and yellow "mustard-like" sludge buildup on the bottom of the oil fill cap. The entire engine is sludged too. It's on an Auto-RX cleaning phase but the lack of reaching full operating temps still allows this aforementioned buildup to occur in the oil fill area. The oil on the dipstick looks fine, like used motor oil should look like.

So, is this a common problem with these engines or is there maybe a coolant leak into the oil? If there is a coolant leak, are there any simple ways to detect it other than doing a UOA or monitoring the coolant level? Maybe a blotter test would detect coolant in the oil? Thanks.

 

[2KBMW]

Jag. As far as I know, BMW engines are not sludge prone
engines. I don't drive my car in winter, but I have seen
some light white/yellow sludge with water droplets under
the oil cap during cold November days. This is normal
water condensation you get in any cold area of an engine.
This does not mean the entire engine is sludged up.
I would take your mothers car for a good highway run once
a week and change the oil every spring time.

PS. I ordered Auto-RX for my BMW and I want to ask you
what oil is being used for the cleaning phase and what
oil do you plan on using for the rinse phase.

 

[JHZR2]

My E30 318i is not a known sludger, but when I would use it for short trips in the winter, I noted a bit of murkiness on the oil filler and dipstick.

Then again, my 318i barely makes enough heat to keep itself warm, so that is part of the problem... in operating, water temps will get into the correct range, but within 5 minutes of turning the engine off in the winter, the gauge is halfway.. IMO, the engines are designed to shed a lot of heat ina lot of places, so perhaps oil doesnt get up to temperature as easily...

JMH

 

[JAG]

Thank you! I knew there were some BMW guys here. Forgive my use of food terms when describing this but...I know it's sludged because: the metal below the oil fill cap has a lot of black "barbecue grill" deposits on it, the oil filter housing has some caramel colored sludge on it, the dipstick has brownie cake sludge on it, and the oil that I drained out of it during an oil change had quite a bit of the barbecue grill sludge in it (I saw it after I emptied the used oil container).

But I do understand what you are saying about the cold part of the engine near the fill cap getting condensation and that running it hard and hot as often as possible being a good idea. In fact I did this while driving it last weekend and it literally made the moisture and mustard sludge go away from the oil fill cap.

From what you said, I doubt it has a coolant leak since you've seen the yellow sludge on the fill cap too. Whoever owned it before my mother must not have changed the oil often enough or let the oil temps get hot enough. That must be why the entire engine is sludged. It holds 7 quarts of oil and that makes it take longer to heat the oil up.

For cleaning phase, it got Supertech Synthetic 10W-30. Maybe not the best choice but probably not a bad choice. For rinse phase, I told her to just let the oil change guy use whatever 10W-30 dino oil they normally use.

 

[2KBMW]

Jag. When I bought my car , there was this reddish brown
residue under the oil cap. Other people complained about this also. It could of been the BMW oil or the extended OCI's. The RX treatment will be good to do. I think for
the rinse phase, a good HD 15w40 will be best for the BMW's.
I've got to go now. All this food talk got me hungry.

 

[JAG]

Yes, I saw the reddish brown residue too. So I think her engine doesn't have any mechanical problems, just filth to be cleaned up. 15W-40 HDEO sounds great in this engine for someone who takes long enough trips but with my mother taking 4 mile trips usually, her 10W-30 oil is already too thick. It's viscosity probably stays above 100 cst most of the time. Thanks for the help from both of you guys above.

 

[nel]

The reddish brown residue is fairly common. If high quality synthetics are used, you may have less. You can't see the valvetrain through the oil cap opening given the way the valve cover is designed.

I know the '97 328i (M52 engine) has an oil change interval of about 9K miles. I'm not sure when BMW started spec'ing synthetic oil but they raised the OCI up to about 15K miles when that happened. If you're unsure about how the prior owner treated the car, I'd use 15W40 at 5k intervals for awhile.

Watch out on the cooling system. The recommended preventive maintenance on waterpumps and thermostats is 60K miles and 90K miles on radiators. The radiator on my '95 525iT went out at 98K miles while on the freeway (this was before I knew better).

 

[Stooge]

But I betcha the newer model BMW's will be "sludgers" now that "Maintenance is Free" and miraculously, the oil doesn't need to be changed every 5K but now around 15K!!

 

[Primus]

I saw a good number of engines (at least models 1987-1999) with open valve cover and those where synthetic or semi-synthetic oils were used and OCI was not exceeded 10-12 Kkm were nearly perfect. However, there were few quite strange cases with later models running on fully synthetic oil and far from to be a long interval: some were dirty inside like a tractor missing a regular maintenance and others where the oil turned into a gelatinized substance.

 

[windnsea00]

The M52B28 is not a sludger like people have said...and I don't actually know of any BMW engines that have been sludgers. Engine quality is something BMW does well and is world reknown for.

Throw some 15w40 in there, take it out on the freeway and run it hard. These engines like to be run (think Autobahn) and will last a long time when maintained.

 

[FowVay]

I have taken the valve cover off of my 1999 323i to see if there was any relationship between the deposits I see on the plastic cap and the metal head surface. The head was as clean as it could possibly be.

I have spoken to many people about what could possibly be causing the deposit formation on the BMW plastic parts. I too thought it was caused by the BMW oil but I haven't used that in my car in over 6 years. The conclusion I have come to is that the deposits are caused by the difference of surface temperatures between components. The in-line six engines seem to have a very well controlled path of air-flow through the engine compartment along with the crankcase ventilation tubing running out of the cover at the front and on the intake side of the engine. With a composite (plastic) valve cover it seems to stay much cooler than the aluminum head and therefore creates a condensation effect on the inside of the cover. The result is the deposits that we continue to see around the upper area of the cover. If you remove the cover you notice that these deposits are only on the upper part of the cover where no oil splashes. The camshafts have their own plastic covers that act as oil sling controls and these covers are very clean. The area under the cover where the timing chain runs is also pretty clean looking.

Just by design the cover has numerous sections of bridges and fillets to give it strength. I believe that these thin, small, plastic pieces act as insulators and this leads to the oil vapor condensation on the inside of the cover which dries and leaves deposits over time.

 

[Big Dave]

I've had several BMW cars. Currently have a '95 M3 since new with 70K miles now. Use M1 15W-50 but will be changing to something else at next OC.(I do 1 year or 5,000 miles) Car is used as a toy so when it goes out I put 50-75 miles on at a time. Inside oil filler cap area is like new. Bright clean metal no deposits or residue.

My M-I-L has a '92 325i with 170,000 miles. I used Valvoline Turbo V 15W-40 during the first 5 years of its life as it was a lease car. OCI's at 3,000-5,000 miles.

She bought car at end of lease so then I switched to M1 15W-50 and did OCI's at 8,000-10,000 miles. Car is in a rural setting so it gets fully warmed up upon use-no short trips. Engine has just a slight amount of amber build up on the metal inside the filler cap area. Uses no oil between OCI's.

David

 

[2KBMW]

Fowvay. Thats good news then if the deposits are only
limited to the underside of the cover. I did hear that
the oil fill area is the ventilation part of the engine.
This explains any condensation, but my question is, do
these engines have a pcv valve?

 

[JustinH]

I would run it hard with a diesel motor oil.

Rotella synthetic 5w40 perhaps?

 

[bmwtechguy]

If you drive short trips always, you must change the oil more often. The crankcase/ oil needs to get hot to burn off any condensation, and if this does not happen, the additives in the oil will get used up more quickly. This problem obviously gets worse with short trips in the cold weather. A synthetic oil may last longer in this type of service, but still needs to be changed, probably way before the oil life indicator says so. Diesel rated oil? Yes, this could help some. I have not seen any negative effects, long or short term using diesel rated oil in these engines. I have used dino 10W-40 in the summer during Auto-RX cycles and dino 5W or 10W-30 in colder weather. But all dino, not even a Group III synthetic when using ARX for me. Heck, you're not running it very long at all. You're spending enough on filters already for one of these. No SuperTechs so far for BMW's...

 

[FowVay]

2KBMW, the M52TU engine does have a PCV valve but it isn't the cheapy one-way valve like on many cars. The PCV is mounted down below the intake manifold and has two diaphragms which are vacuum controlled. The hose running from the valve cover and down beside the oil filter housing will lead to the PCV controller. You have to remove the air filter housing, intake duct, and power steering reservoir to see it.

As for replacing the oil frequently and paying for the filters, I pay $4.04 for Mann filters and $4.19 for Mahle filters from a on-line supplier (I prefer the Mann product in this application). It doesn't get much less expensive than that.

 

[JAG]

Thanks for all the good info fellas!

 

[Leo]

In my olds E39 530i it has the reddish residue in the filler cap area. However I peered into the valve train with a torch and it looks darn clean. I think its just that the filler cap is the highest point in the rocker cover so the oils vapour when it 'boils off' leaves the deposits there. I also notice this stuff on the dipstick.

Nevertheless I change the oil midway through the OCI spec'd by BMW's OLM. (Typically about 10k miles out of the 20k it goes) Btw whilst under the BMW today I noticed there was something in the sump with an electrical harness plugged into it. Anyone know what it is?

 

[Ray Garlington]

Quote:

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I noticed there was something in the sump with an electrical harness plugged into it. Anyone know what it is?

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This is probably the oil-level switch. It triggers a warning when you are about 1/2 litre low.

 

[Jett Rink]

My only firsthand experience is with the M20. No reputation for sludge in that one. Mine has had a life of oil changes of mostly 15w-40 dino, usually around 5,000 to 6,000 miles, according to records of previous owners. I've never heard of older BMWs having sludge problems. The only BMW sludgers I have heard of is for the recent years, where people are going 15,000 miles without changing their oil, even though the BMW synthetic is a pretty stout oil.

I just did a valve adjustment over the weekend on the M20. There's a healthy amount of varnish in there, enough to make some BITOG members have a heart attack. My birthday is in March, perhaps the wife will give me a digital camera, so I can takes some pics and post to the board? I've considered trying some of this Lube control stuff. It is advertised as removing varnish, so this would be a good test of its claims.

If you want to do some preventative maintenace on your car, I'd give the coolant system a thorough inspection. I just replaced a leaking radiator on mine. If yours is original, it might be living on borrowed time. I think I read where some models newer than mine have an iffy water pump, plastic parts that deteriorate, or something like that.