Hi,

I have a DS DS5 (not branded as Citroen) powered by a 2.0 BlueHDi 180 diesel with a 6 speed auto. It's a 65 plate with 17k on the clock. I got it three months ago and have put 3k on it. It does regular short journeys and as such doesn't get up to temperature. However it often gets good long runs at speed, the last being 500 miles over Christmas up to Aberdeen and back. I've always filled it up with Shell V-Power Diesel.

Today I went on a short run of about 10 minutes to the supermarket, and back home again after about half an hour. The engine temperature guage didn't even register any heat on either part of the journey. When I turned into my driveway I could smell burning, just like you get when lighting a barbeque using lighter fluid. I stopped to reverse and saw alot of smoke from the rear of the car. My driveway is quite tight to turn round so it takes a few movements to turn fully. Each push of the accelerator gave off more smoke. I stopped and revved it again - lots more smoke, a kind of white/grey colour. I checked the dash, no warning lights or messages or fault indications. Temperature guage hadn't even registered any heat (it's a digital one) and AdBlue level was sufficient. Revved it a few more times and more of the same smoke came out. With the engine still running I opened the bonnet and the smoke smell was in there. I revved the engine again and could see the same smoke coming from behind the engine block. Checked under the car and could see nothing escaping from the exhaust. I took the cover off the engine for a better look and could see nothing untoward, no obvious leaks. Coolant level was normal and the oil level too, although I did notice a few bubbles on the oil on the dipstick. I also found a little bit of mayonnaise under the oil filler cap. During this time the radiator fan came on and the temperature guage had risen only to the first mark, which is 60 degrees. Despite all of this, the engine sounds like a diesel should - no knocks, is steady and quiet (for a Diesel).

I'm thinking a few things here:

First being that I've interrupted it's DPF regeneraton procedure. However, it's nowhere near up to temperature and hasn't got to the desired speed - I might have just hit 30 mph briefly after a cold start under urban driving conditions. Although I'm not altogether familiar with the Euro6 Diesel workings I'm sure a DPF regen won't have started under the above conditions.

Secondly, I've got water ingress into the engine block ie cylinder head gasket failure (I hope not) looking at the white smoke and mayonnaise under the filler cap.

Thirdly, could the mayonnaise under the cap be due to the short runs? Any moisture in the engine hasn't had a chance to dissapate?

Has anyone else experienced similar? Does it just need a good run (which I was planning to do tomorrow) or does it need a visit to the Citroen garage before I do any damage?

Thanks in advance