Burning smell after motorway journeys?

[Abz115]

Car: 2015 Mercedes B180d
Mileage: 90,000
Daily Commute: 25-30 minute motorway journey to work and back. (15 miles each way) - sometimes this can be speeds of 40-70mph depending on traffic, slow down during journey and speed up. It’s not always a consistent thrash for 70mph.

For the past few weeks after my daily commute I come off the motorway junction and stop at traffic lights. Immediately I notice a burning smell coming into the cockpit (I usually have my heaters on so it comes straight in). The burning smell is like a rubber/oily smell.

Last week my mechanic noticed my turbo pipe was leaking oil (boost pipe) and I had this replaced yesterday. However, this burning smell after the motorway journey still persists. It only lasts for about a minute then as soon as I’m back to city driving it’s fine.

Engine isn’t overheating, no signs of reduced performance etc. Today I’m not sure if it was from outside but I also noticed some white smoke coming from the engine bay after the motorway drive (I was in sport mode and using high revs) which also made its way into the cockpit as my heaters were on. I thought the car was going to set on fire!!

Now after searching around I’m not sure if these are signs of my car completing a DPF regen and not fully completing its cycle or is this something else?

Thanks I’m advance.

 

[Flyinspanner]

Maybe oil dripped onto exhaust from that split pipe, and maybe got a bit more during the change of pipe.

give it a day or two to all burn off then check your exhaust for any oil drip evidence on it. Look for where it’s from.

(it may all burn off after a couple of days and not be a further issue)

 

[PaulMason]

Maybe totally different on a newer car, but my 2004 SLK 350 has little plastic plugs in the back of the heads which were leaking and the passenger side one is directly over the exhaust so it would drip a little then as the car got warm started to burn, but would then go after a while.

 

[Bobby Dazzler]

Burning rubbery smell after a high speed run does indeed sound like a DPF regen. It would smell anyway but when driving at high speed the smell should dissipate, but at low speeds - or when stationary - the smell can become quite intense.

You really need to confirm or eliminate the possibility of a DPF regen. Someone who knows what they’re doing with STAR or another diagnostics tool maybe be able to see if there’s been a recent regen - successful or failed - to help you work out whether it’s that.

Alternatively, when you can pull over and stop when you believe the regen is in progress, if the engine cooling fans are going mad at low speeds or stationary - and continue to do the same even when you switch the engine off - then it would suggest a DPF regen is in progress.

 

[Abz115]

Burning rubbery smell after a high speed run does indeed sound like a DPF regen. It would smell anyway but when driving at high speed the smell should dissipate, but at low speeds - or when stationary - the smell can become quite intense.

You really need to confirm or eliminate the possibility of a DPF regen. Someone who knows what they’re doing with STAR or another diagnostics tool maybe be able to see if there’s been a recent regen - successful or failed - to help you work out whether it’s that.

Alternatively, when you can pull over and stop when you believe the regen is in progress, if the engine cooling fans are going mad at low speeds or stationary - and continue to do the same even when you switch the engine off - then it would suggest a DPF regen is in progress.

Yes I think it may be the case of the DPF regen not being completed as my commute to work is slowed down then speed increases. I’m aiming this weekend to do a 140 mile round trip journey on the motorway, hopefully that sorts it out.

 

[TeddyRuxpin]

DPF regen alone shouldn’t cause smoke, you likely have an oil or diesel leak

 

[ALFAitalia]

Agreed....regen won't stop just because you slow down either , only if you stop and turn.the engine off. There should only be traces of oil in a boost pipe (none at all in a perfect world....But usually there is a bit)...sounds to me like you have another small oil leak that's dripping into something hot like your exhaust.

 

[TeddyRuxpin]

I had a diesel leak from the fuel line that only showed smoke during a DPF regen. It was difficult to track down as it was inconsistent and I was new to diesels and regents etc.

I’ve also had a ton of other fuel and oil leaks

Good times