[vrracing]

2008 335i 6MT with 80k. Walnut blasted and new plugs. JB4 is inactive and only other visible mod is DCI.

The car runs well at idle and full throttle but at low acceleration (stop and go traffic) or going up hills there is a surging as described in this thread Light Throttle Hesitation.

No active (non-shadow) codes except the ignorable fuel pump plausibility code. The car has DCI so discerning a boost leak would be difficult.

Got a 1" cap (really a rubber table leg foot) for the PCV and did a pressure test. The back DV has an audible leak bubbling at the gray locking mechanism at 5psi. If i push the DV towards the engine, it will stop leaking.

I searched for "DV o-ring" but only saw hits for Forge DVs.

Seems like the CP to DV seal is weak. Is the o-ring replaceable or is a VRSF CP a sooner rather than a later?

No other discernable leakes unless I take it above 15psi at which point the rear turbo inlets sings as expected.

Thanks,

Jim

[Sgop335]

Yes they are replaceabl, will try to find the size...or just measure and match

[vrracing]

Thanks for the quick response, Sgop335. In parallel I Googled outside the forum and found this post.

I got a pair out of my HF metric o-ring set and it was at position 214 No. P25 W3.5 I.D 24.7.

That post suggests removing the grey locking clips suggesting it is easy. But in my experience BMW sources plastic from the socialist side of the country and so it shatters if you look at it funny. I was able to get the o-rings out with a pick. Carefully slid em in and then put some grease on them before sliding in the DVs. Repressurized and no more leaks on that side.

We'll see how they hold up and if that fixes the low throttle surging.

[Sgop335]

Yes remove orings w a pick. That size looks ok, good job.

[vrracing]

Good reference, Sgop335.

For future searchers, the new o-rings fixed my part throttle, high load stumbling.

[320IN54]

Ive heard people saying that the o ring used in the chargepipe is the same one in the oil filter housing. I have not yet tested it but it actually be true due to the same size

[Chris@VargasTurboTech]

Originally Posted by GotPwned

Ive heard people saying that the o ring used in the chargepipe is the same one in the oil filter housing. I have not yet tested it but it actually be true due to the same size

No -it's a little bit different. In a pinch, you CAN use the oil filter gasket o-ring but it'll leak.

Correct O-Ring P/N for charge pipe/throttle: 13717568031.

-Chris

[320IN54]

Originally Posted by Chris@VargasTurboTech

No -it's a little bit different. In a pinch, you CAN use the oil filter gasket o-ring but it'll leak.

Correct O-Ring P/N for charge pipe/throttle: 13717568031.

-Chris

Thanks for confirming it then. This is very good to know especially cause a lot of people believes that the two o-rings are the same.

[vrracing]

Just to clarify for any future readers, 13717568031 is the big o-ring for charge pipe (cp) to throttle body (tb) connection.

The o-rings that are the focus of this thread are the two much smaller ones for the two charge pipe (cp) to diverter valves (dv) connections. Wouldn't want someone to go and buy two $5 o-rings for their dv's only to find they wont fit.