[K328i]

Hi guys. Looking for some guidance..

I have a 2013 Bmw 328i F30 M sport 57k miles N20 engine (uk) & after a recent oil change to 0w20, the oil was so thin that it seeped into the turbo overnight and caused a puff of blue smoke on start up.

Turns out in earlier models bmw didn’t put a check valve in the turbo oil feed line.

Last week I DIY’d it myself & took the turbo out of the car to change the turbo oil feed line with the updated one with the check valve. Everything seems perfectly fine no check engine lights she’s boosting perfectly fine, still feels like a 245bhp car with plenty of low end torque.

My issue is that I used to get loud throaty cold starts which really turned some heads in the morning and for a stock exhaust it sounded awesome. YouTube some 328i f30 cold starts & you will see why. But since the feed line change I don’t get the throaty cold starts anymore. Even if the cars been sitting for 2 days, the revs don’t jump up anymore and the car is quiet on startup now.

Would anyone know the cause of the cold starts not happening (as weird as that may sound). I’ve outlined some possible issues below

- Exhaust leak
- Wastegate actuator out of adjustment ( although no engine light)

I would really appreciate some help on this as I’m worried further issues may arise.

[pshovest]

Is the exhaust flap in the rear muffler working properly?

[Wires]

The wastegate valve (or diverter depending on engine) opens during cold start to bypass the turbo to pre-heat the cats. That's the "cold start roar". If you have lost that, that's where I'd be looking.

FYI: "after a recent oil change to 0w20, the oil was so thin that it seeped into the turbo overnight" isn't even a thing. At night, that oil is 20W which is thick. Almost every BMW is shipped and serviced with 0W20 for fuel mileage reasons.

[sqwinny]

Did you change the o ring on the line as well? That's a known thing to go bad as well. I can't recall if it comes with the line when you buy the updated version. Otherwise I'm going to assume you have a leak somewhere

[K328i]

Originally Posted by pshovest

Is the exhaust flap in the rear muffler working properly?

I believe so. After a minute or so I can hear the flat open/close at the rear so that seems to be working fine

[K328i]

Originally Posted by Wires

The wastegate valve (or diverter depending on engine) opens during cold start to bypass the turbo to pre-heat the cats. That's the "cold start roar". If you have lost that, that's where I'd be looking.

FYI: "after a recent oil change to 0w20, the oil was so thin that it seeped into the turbo overnight" isn't even a thing. At night, that oil is 20W which is thick. Almost every BMW is shipped and serviced with 0W20 for fuel mileage reasons.

Before the car was serviced I used to 5w30 and no issues. As soon as the 0w20 was used the smoke on startup problem happens. Cars in USA had a recall but uk ones didn’t so people have been doing the oil line change themselves.

I have the electrical wastegate. My engine is an N20. When I push start button (without starting car) the wastegate flap opens and closes - I know this is normal as it find the min & max travel distance. Where would I find the diverter valve?

[K328i]

Originally Posted by sqwinny

Did you change the o ring on the line as well? That's a known thing to go bad as well. I can't recall if it comes with the line when you buy the updated version. Otherwise I'm going to assume you have a leak somewhere

Yea the new oil line came with new O rings. Also the coolant line O rings were changed as I needed to remove them from the turbo housing. I’ve checked for leaks and can’t see any.

[Wires]

Originally Posted by K328i

Before the car was serviced I used to 5w30 and no issues. As soon as the 0w20 was used the smoke on startup problem happens. Cars in USA had a recall but uk ones didn’t so people have been doing the oil line change themselves.

I have the electrical wastegate. My engine is an N20. When I push start button (without starting car) the wastegate flap opens and closes - I know this is normal as it find the min & max travel distance. Where would I find the diverter valve?

Oh, if you have an electric wastegate, I don't think you have a diverter valve.

[K328i]

Originally Posted by Wires

Oh, if you have an electric wastegate, I don't think you have a diverter valve.

I googled the diverter valve for my car model but all I can find is the blow off valve.

I’m edging towards a exhaust leak from when I put the downpipe/car back on. Hopefully it’s not too serious. I want my morning cold start roar’s back!

Actuator is not throwing any fault. No CEL. I ragged the hell out of the car today and yesterday in all eco,comfort,Sport & sport +. Still no CEL. I must have one damn good built bmw

If anyone can think of anything else which could be the issue for no cold starts, please comment below..

[Wires]

I doubt it would be an exhaust leak, but having the cat damaged/turning in the DP could block airflow enough to get rid of the roar.

Did you tune it as well? BM3 has a slider to disable the cold start roar. i did on mine, as it was annoying with the catted ER HP + axle back.

[K328i]

Originally Posted by Wires

I doubt it would be an exhaust leak, but having the cat damaged/turning in the DP could block airflow enough to get rid of the roar.

Did you tune it as well? BM3 has a slider to disable the cold start roar. i did on mine, as it was annoying with the catted ER HP + axle back.

No I’ve not tuned it & I don’t think I will. I’m building this car to be more on the reliable side rather than performance. It’s very punchy for a 4 pot as it is with 245hp 400 torque.

On the up side though, I thought I’d put it in Sport+ mode before starting it up 7am this morning and hey presto.. the car roar was back! Fired it up again at work 2pm this time in normal comfort mode and it did the cold start roar again! The relief I felt was unimaginable! A few more trials over next few days in both Sport+ and comfort before I take it to a friends garage. Might have him take the cat off and reapply seeing as I did it on jack stands and he has car lifts.