The start of something bad? - Engine Advice.

[Stella Artois]

The M12 recently has started with a couple of issues. Since I bought the car at the beginning of July it has never failed me, I have gotten used the rough running on start up, which, having spoken with Yellowshed is probably down to the mapping. This I was going to address at the beginning of August, but as I'm close on needing a new exhaust (Perforation poisoning - Original) I thought I would leave this until I had a new one fitted. It was commented at work that it "puffed" some blue smoke on startup, I initially never gave this too much thought as the comment was made by chap who spends most of his time telling me how bad the Noble is, taken with a pinch of salt as his pride and joy is a slightly tired Skoda Estelle. It is however, now noticeable on every start. With the oil temp below 50º applying the throttle emits light blue smoke. With the temp above 50º nothing, no matter how the car is used. This is where I'm a little confused, I would expect dark smoke at cold startup leaning toward gummed up piston rings or light blue smoke on throttle lift off, indicating valve stem oil seals. The manifolds have cracked in the past and have been welded and strengthened and don't appear to have suffered again. Both Turbo's were replaced last year. The oil level remains constant and I have patch tested a sample of the oil and it is remarkably clean. The car has been meticulously serviced (Noble), but is due another one soon (30K) service. It gets used a lot though, at the current rate, 28K a year.

Any thoughts, without the scaremongering - £10k rebuild suggestions

[roi354]

I'd have thought the blue smoke on start up was turbo oil seals. I know you said they're fairly new but thats still the first place I'd look. Whip off a turbo-IC hose and see if theres a trail of oil in there before you start thinking really expensive.


Rob


EDIT to add: Do you allow the oil to cool before you shut off the engine? Its wise to allow things to cool a bit slower otherwise you could end up with premature turbo wear/failure.

Edited by roi354 on Thursday 17th September 21:59

[joust]

Sounds like a turbo on the way out. Tadts and it's not that expensive. Check the gaskets first though.

J

[Stella Artois]

roi354 said:

Do you allow the oil to cool before you shut off the engine? Its wise to allow things to cool a bit slower otherwise you could end up with premature turbo wear/failure.

Yup, always a 2-5 minute cool down before the engine is killed.

[Jim O.]

As Rob suggested, pull off some of your I/C piping and check for oil residue. If the piping is clean, you might want to get your engine compression and leakdown tested. That should uncover bad rings, valve guides, etc.

[fhwong]

When you say a 2-5min cool down. Is that running the car at slow speeds for the last stretch of road home .. or do you let it sit idling for 2-5mins before turning off the engine?

Just want to find out what I need to do.

[joust]

Driving for the last few miles without creating boost (i.e. very gentle throttle) is an excellent way to cool things down.

J

[Stella Artois]

fhwong said:

When you say a 2-5min cool down. Is that running the car at slow speeds for the last stretch of road home .. or do you let it sit idling for 2-5mins before turning off the engine?

Just want to find out what I need to do.

Both really, I have about a mile of restricted road prior to arriving at work so its not on boost, then I let it sit for a while as I get all my stuff together, ready for the falling out part.