[delorean175]

Hello all,

I'm moving from Washington state to Texas in a few months, I'll be driving my 2013 335i Xdrive 2K miles. My car is at 181K miles right now. I'm pretty new to the n55 engine, I'm more familiar with the n52. My main concern is to prevent getting stranded on the side of the road or (ideally) not go into limp mode. Below is the maintenance I've done within the last 5k miles. All fluids changed, coils, plugs, oil filter housing gasket, serpentine belt, tensioner, idler pully, metal charge pipe, thermostat, walnut blasted the intake valves (they really weren't that bad at all).

The Tstat was original and still functioned correctly, my heat sucked and I suspected the Tstat was to blame. So I replaced it and the heat still sucked. For context I read when the Tstat goes bad the water pump isn't far behind.

I have a few issues that I don't think would leave me stranded on the side of the road, please tell me if you think they could.

I hear a subtle whine sound at low RPM, it's most audible at 2k RPM's. The tone of the whine changes with the RPMs. I'm not sure what it is. I've looked at other videos and haven't found anything like it. Currently my car shows no codes at all and it drives fine. I'm not sure if its normal or not. At idle it's hard to detect where it's coming from. I'll keep investigating it. Hopefully it's not something that will leave me stranded on the side of the road.

Sometimes In sport mode while taking off from a stop, if I lightly accelerate I feel like the car lurches forward a little bit. Kind of like it wants to go faster than I'm making it go. I stumbled on a thread about the diverter valve could be to blame. It's cheap to upgrade so I may do that anyways and see what happens. Sometimes I feel like the car is slightly underpowered, other times I feel like its a little quicker. Also I think I have a slight waist gate rattle, but I read people go a while with the issue until it becomes loud and obvious. I'm not sure if that could be the source of the lurching or not.

Once in a while the car goes into limp mode and the cooling fan runs on full blast. I read this could be an issue with the cooling fan. When it happens I pull over, turn the car off and on, problem goes away.

One concern is my water pumps. When they go bad is it sudden or do they throw codes prior? I put a long screw driver up to the side of my pumps during a bleed procedure, it sounded smooth and purred. I have the Msport package so I have 2 water pumps.

Also my wife will be driving her 07 X3 3.0si as well. So water pump is a concern for her car as well. Also her eccentric shaft sensor may be to blame for some little hiccups and stumbles while driving so I'll be replacing that.

Any input would be greatly appreciated!

[F32Fleet]

cooling fan is sometimes indicative of pending water pump failure.

[delorean175]

Originally Posted by F32Fleet

cooling fan is sometimes indicative of pending water pump failure.

Really? Interesting. I'll have to look into that. I appreciate it!

[cfm56d7b]

You already replaced what I would have suggested: OEM charge pipe.

Did you replace HPFP? Or is it still the original one?

[F32Fleet]

Originally Posted by delorean175

Really? Interesting. I'll have to look into that. I appreciate it!

Ya, As I understand it the DME increases fan speed when the pump begins to have problems sustaining the required flow.

[delorean175]

Originally Posted by cfm56d7b

You already replaced what I would have suggested: OEM charge pipe.

Did you replace HPFP? Or is it still the original one?

I didn't change it. The PO may have. I'll have to check to see if there's a date of manufacture on it.

[delorean175]

Originally Posted by F32Fleet

Ya, As I understand it the DME increases fan speed when the pump begins to have problems sustaining the required flow.

Ahh ok that makes sense. I'll have to keep an eye on the fan speed. I've had it run at full speed once or twice before. I remember thinking it was odd because It was running full speed after driving around on a day where it was like 70F.

[cfm56d7b]

Originally Posted by delorean175

I didn't change it. The PO may have. I'll have to check to see if there's a date of manufacture on it.

If the OEM HPFP lasted 180K+ miles, that would be a record of sorts. Definitely worth checking with the previous owner.