E91 Straight Six Bearding

[JakeT]

helix402 said:

Anyone tried the XHP gearbox software? My 335d could do with a better change, it’s getting the latest BMW software and new oil&filter first.

Sir Dave had it on his 335d and even with mega miles he said it made a big difference. Stage 2 is meant to be bang on for road driving.

[helix402]

JakeT said:

Sir Dave had it on his 335d and even with mega miles he said it made a big difference. Stage 2 is meant to be bang on for road driving.

Thanks.

[g3org3y]

Swervin_Mervin said:

It's not that odd for there to be no service history for the box as BMW treat them as "sealed for life". The fact that ZF do service kits should tell you all you need to know.

My advice is get one done. It can't do any harm and may do it some good. I had mine done around 80k.

but bear in mind, it isn't cheap.

[Jakg]

skullandbiscuits said:

My E91 330d is approaching 160k. What is the general consensus on auto box service if you cannot see in the history that it has been done before?

I would (and did).
I'd consider changing tube seals too.

https://www.pistonheads.com/gassing/topic.asp?h=0&...

If your going to do it, though, do it properly - genuine ZF oil and ensure you follow the fill process properly. Otherwise you might make it worse.

I have heard stories of very worn clutches only working due to stuff suspended in the fluid and when you change it, it stops working - but in that case you were on the brink of a breakdown anyway. Not sure how true it is though.

[DC.11]

helix402 said:

Anyone tried the XHP gearbox software? My 335d could do with a better change, it’s getting the latest BMW software and new oil&filter first.

I’m contemplating getting mine done (N57) as I find the box is stopping me from fully enjoying/gelling with the car. I’ve recently had the box serviced, and it’s smooth enough, just feels too slow to lock up.

[Fulla]

DC.11 said:

I’m contemplating getting mine done (N57) as I find the box is stopping me from fully enjoying/gelling with the car. I’ve recently had the box serviced, and it’s smooth enough, just feels too slow to lock up.

I have a 335i petrol with the stage 2 and mapped for 99 fuel with the N55 engine.
In normal auto mod it is smooth and great for town driving or for when you are just cruising around. Put it in sport though or use manual shifts and it comes alive. It's like a different car, obviously it holds onto the gears for longer but it's like you have pushed a switch for a power boost.

[g3org3y]

What's the normal operating temp for an N52?

My 630 has the oil temp gauge instead the mpg swingometer in the E91. Today, for the first time it crept up to 120.

I assume this means it need a new thermostat:

[JakeT]

g3org3y said:

What's the normal operating temp for an N52?

My 630 has the oil temp gauge instead the mpg swingometer in the E91. Today, for the first time it crept up to 120.

I assume this means it need a new thermostat:

If that's oil, that's warm. Coolant can go as high as 110 on these engines when they're in eco mode. That code normally means the thermostat is goosed. I did the pump and thermostat at the same time when I had the code.

[helix402]

g3org3y said:

What's the normal operating temp for an N52?

My 630 has the oil temp gauge instead the mpg swingometer in the E91. Today, for the first time it crept up to 120.

I assume this means it need a new thermostat:

Yes, new thermostat ideally.

[g3org3y]

Thanks chaps, will get it booked in.

As an aside, noise evident when the AC is on (ceases when AC off) - suggests a pulley or the compressor itself. The AC itself is still cold.

If I'm getting it booked in for the stat and AC (pulley/compressor) what else is worth changing? Obviously belt, what about any other pulleys, tensioner etc?

[JakeT]

My compressor bearing failed at 152,000 miles. It worked but make an awful noise, AC on or off. I put a new Denso unit in from Opie oils. A Denso one came out of it.

If it’s original, I’d have the belt tensioner replaced. They bend inwards over time and the failure mode can cause the belt to get sucked through the front main seal. An INA tensioner is the OE part and roughly £70 I think.

[pmorg4]

You can get them a lot cheaper on eBay, I bought from these guys for ~£37:

https://www.ebay.co.uk/itm/163253703733

Genuine INA part with the (required) replacement bolt included. Looked identical to the original BMW part that came off, with the exception of being a lot cleaner!

You can also get the genuine INA idler pulley from the same seller for about £16, so you might as well replace it too while the belt is off.

[Nuisance]

Any thoughts on this please folks? Aside from it being absolutely filthy and a terrible advert, of course.

http://www.autotrader.co.uk/car-details/2021031200...


I know these are rare in facelift form and command good money but it's still a little toppy price wise, I think?

I know the N55 is supposedly slightly more reliable than the N54, I've had a bit of a flick through some old threads on here. I didn't realise they were DCT (or rather I hadnt put 2 and 2 together, given that I know the 135i was DCT) rather than conventional auto though.

[helix402]

It’s not DCT. It’s the ZF6HP something. I think it’s too expensive. But they are rare.

[Nuisance]

helix402 said:

It’s not DCT. It’s the ZF6HP something. I think it’s too expensive. But they are rare.

Oh, ok, thanks. I didn't think it was initially but I'm sure I read somewhere yesterday that these were DCT.

At least you've confirmed what I thought about the price.

[Swervin_Mervin]

On a completely unrelated note, and prompted by a comment I saw elsewhere about the latest Alpina D3, does anyone know why the E91 D3S is listed with a kerbweight of 1935kg vs the 335d at 1645kg? I can't believe for a second that the Alpina is almost 300kg heavier.

I assume they're just weighed differently by BMW vs Alpina?

[gizlaroc]

DCT was available, on the E92 anyway.

[helix402]

gizlaroc said:

DCT was available, on the E92 anyway.

The one in the ad looks to be an auto.

[Nuisance]

I did notice the conventional auto lever. I'd prefer that in a daily driver anyway.

[g3org3y]

JakeT said:

My compressor bearing failed at 152,000 miles. It worked but make an awful noise, AC on or off. I put a new Denso unit in from Opie oils. A Denso one came out of it.

If it’s original, I’d have the belt tensioner replaced. They bend inwards over time and the failure mode can cause the belt to get sucked through the front main seal. An INA tensioner is the OE part and roughly £70 I think.

pmorg4 said:

You can get them a lot cheaper on eBay, I bought from these guys for ~£37:

https://www.ebay.co.uk/itm/163253703733

Genuine INA part with the (required) replacement bolt included. Looked identical to the original BMW part that came off, with the exception of being a lot cleaner!

You can also get the genuine INA idler pulley from the same seller for about £16, so you might as well replace it too while the belt is off.

Thanks lads

Re the belt - Gates or Continental?

Re the thermostat? - Which brand. OEM was Wahler on the E46 iirc.

Edited by g3org3y on Monday 17th May 21:05