Welcome to Tech Talk, where our resident BMW tech Nick Owen answers all your pressing BMW technical questions, frustrations, and issues. Have a question for Nick? Email him at techtalk@roundel.org. Let’s get into it.
Solving the Three Amigos
I am using Redline 5W40 (Red Bottle) in my S62 engine and it appears to work perfectly. As a test, I did a 6000-mile change interval with Blackstone analyses at 3K and the contaminants were very low. Based on multiple TSBs over many years, BMW could not make up its mind if 10W60 TWS or 5W30 magic dealership oil was appropriate for that engine. Since CAFE mileage was never a consideration for the S62, RL 5W40 has a HTHS viscosity close to a 10W60 and holds 20+ psi pressure idling hot, it appears a good compromise. Given the cost of rebuilding that engine I think 3K to 5K change intervals are great insurance. At 78K, everything inside visible through the oil filler cap is shiny.
I recently watched a F10 Turbo M5 at auction and was appalled at the lack of proper instrumentation for such a high-performance car. It does have an oil temperature gauge but no boost or oil pressure. My wife’s F22 has the same lack of information. At least my E39 has water temperature, oil temperature, that variable red-line and now a small oil pressure gauge. And let us not forget the dip stick. If I am going to spend well north of 100K for a performance machine, I want to know what is happening under the hood so I can treat it properly. What happened to the “Ultimate Driving Machine”? Perhaps my E39 M5 was BMW’s last UDM.
Fred Staudinger
North Salem, NY
In my opinion, the E39 M5 is the best all-around BMW of all time. Probably their biggest moment in their most recent history of producing the Ultimate Driving Machine. Even though the M2 is pretty good also. But for a sedan, the M5 is king.
Enjoy yours. I envy you.
Oil Loss in 2018 M4
I have a 2018 M4 coupe with about 48,000 miles. I track the car 8-10 times/year from late Spring to early Fall. The car has a highly modified suspension and has Dinan air and flash tune upgrades that increase the hp to about 520. After coming back from the last HPDE for the year the oil light came on, and the car needed a quart of oil. The car is not leaking any oil so it must be burning it. Until now I have never lost a drop of oil from this car. What would you recommend I do before tracking the car again?
Tom Inzana
It sounds like the car is naturally consuming oil considering you are going on track often and the modifications for increased power. While you may have not experienced any oil loss, it’s not uncommon to have to add oil after an HPDE. There really isn’t any preventative maintenance you can do except carry an extra quart in the trunk just in case. I would just ensure the oil level is full and keep an eye on it. If I’m not mistaken, consumption spec for the S55 is 1.5L per 1,000km. While I’ve never done this, I’ve read that you could up the weight of the oil to a 5W-40 (for example) which might hold up better to the heavy track use. I can say that when I was crewing the F82 GT4 in WRL/SRO the last couple of years, we used straight 30 weight oil and never really had an issue. I would continue to monitor the consumption before worrying about condemning a failed component for now.
Thanks Nick. I have had Redline 10W-40 oil in the car. Thing is, this is the first time I have noticed the car consume any oil between yearly changes. So, you do not think I need to bring it in and have it checked for worn rings or other?
Correct, I do not think anything abnormal is happening. Oil is going to be consumed in small amounts here and there. If a symptom develops or the consumption becomes consistent then we can re-address the issue.
530iT woes…
I am having trouble with “New Doug,” my 2001 525iT auto, turned 530iT five-speed.
A little background: The chassis has 155k miles on it and the 3.0 with five-speed was installed about three years ago. As I am keeping up with maintenance, I replaced all the control arms and tie rods a few weeks back. I made a mistake while reinstalling the auto level sensors in the rear and one of them was installed backwards. When I got it back on the ground, the air suspension did not inflate correctly (it was leaning and the SLS light was on). Once I realized what I did, I reinstalled it and brought it in for an alignment. Everything went well and the car drove amazingly well… for two days. My wife picked me up in it and it was sagging like a low rider. The bags were completely deflated. Thankfully, it was not a long ride home. Here is where it gets interesting.
I grabbed my Foxwell to scan the sensors and module, etc., and there was no power to the OBD port. It worked great two weeks ago when I reset everything before the alignment. I tried the scanner in another car, and it works fine so now I have a car squatting like a cat ready to pounce and no way to diagnose it. Here is what I have checked so far:
- I started with fuses. Everything in the glove box was good, as were all of them in the trunk. I even replaced a couple that were a little long in tooth, with no luck. Then I went to the OBD port, thinking that once that is good, I can reinflate the bags. All wires are connected, but there is no power to the wire going into the port. The battery has a full charge (it is on a battery tender as I type).
- I thought maybe it was the module in the back causing issues with the OBD, so I pulled the module and rechecked the OBD while it was disconnected. The SLS light came on (expected) but no OBD power. I reconnected it, SLS light goes off, no OBD power, no airbags, and the compressor does not kick on.
- I jacked up the car a bit in case the sensors were beyond their limits (something I read about online) hoping it would recognize it…nope.
- I pulled the compressor. There is power going into the relay but not out. I jumped the connection and the compressor works. Bad relay? Or does the module control this?
- While the compressor was running, the bags did not inflate. Again, this makes me think the module is preventing the air from getting to the bags. The bags were replaced about two years ago, and I guess it is possible they are leaking, but that would not account for the lack of compressor coming on or inflating at all (I think…)
- I read that there are fuses under the carpet on the passenger side so I pulled the carpet and checked those. All had power on both sides indicating good.
- I did not check the box in front of those fuses that apparently has a power connection to the OBD. I learned about that after I reinstalled everything. I will get to that soon depending upon what you suggest after this novel. Here’s the video:
Right now, I am leaning toward getting a replacement SLS module and relay, but before I fire the parts cannon, is there a way to test the module? Are these two items (OBD and SLS) related? Could the module have fried something else? I am stuck! Thank you for any help you can give.
Bryan in San Antonio
Yes, the OBD has its own power which you should check. You are going to have to start here before looking at other fuses and relays as they will not have influence over your current issue. OBD and SLS are not “related,” therefore a failure on the SLS system does not bring down OBD communication.
In regards to the air bag system, you will need to get a fault scan done to see what faults you have before you can start condemning other parts. It is possible you are dealing with a bad relay or module, or even a compressor. Can your scan tool command components? Meaning can it turn on the compressor to see if it works? This will ensure the relay and module are in fact working. I do not think you have an airbag leak; I think the compressor is not coming on when told or poor air pressure output and therefore the rear sags. This could be anything from the relay, the module and/or the compressor.
Try to keep the weight of the car off the sagging airbags to prevent them from being damaged. Seen this a lot on X5s back in the day.
