Volvo V40

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Wed 22 Dec 2004 21:39
Volvo V40 - boatman
I bought a Volvo V40 estate (petrol injection/Mitsubishi engine) second hand in July 2001. It had done 30,000 miles in the 18 months since it was first registered.It went for its 70,000 mile service/MOT 4 weeks ago, but failed its emissions test very badly. My garage suspected that it needed a decoke, something that I haven't heard mention in about 25 years! Boy, did it need a decoke. The valves, inlets, injectors, piston heads were more-or-less submerged in the stuff. It was finally cleaned up and put back together again.............and it cost me the wrong side of 2 grand.
How can this have happened?.................I'm hearing that these Mitsubishi engines are liable to do this, even after a lower mileage than mine............has anyone had a similar experience, and what reasons were given for it happening?
Volvo simply say that they are not aware of any coking problem in their cars..............So I wonder why they stopped using this engine a year or so ago. I suspect that there is a basic fault of some kind which causes coking.............I'd appreciate hearing fom any one who has had similar experiences.
Boatman
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Thu 23 Dec 2004 20:17
Volvo V40 - SjB {P}
Is it the Mitsubishi Carisma (an oxymoron if ever there was one) GDI (Gasoline Direct Injection) engine? If so, I wonder if it requires low sulphur fuel like the Audi FSI (direct injection) engines, and if not so fed, could suffer malaise such as you described? I must admit though that a colleague has run a Carisma GDI for yonks without any problems (other than crashing it more than once), and your example is the first I have heard of such a problem.
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Wed 29 Dec 2004 14:31
Volvo V40 - derbyshiresteve
Did you run it on supermarket petrol or Jet petrol ? I gather that they contain very little poor quality additives designed to reduce coke build up. Use Shell/Bp/Total/Esso/or Texaco petrol.

{Post edited. DD}
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Tue 27 Sep 2005 12:14
Volvo V40 - Weeneilly
I bought my Volvo V40 GDi from my father at 43k and it already had noisy tappets. My father tended to drive in one gear too high and labour the engine (4th gear at 30mph etc), never booting it.

With 128bhp, the car pulls away without needing to put the foot down, but this means the engine never gets a good blast through with the throtle fully open.

My car is now at 78k and running better than ever.
I believe driving style has much to do with the coking problem.

1. I drive it very lean, never letting the rev drop below 2000.
2. If I need to accelerate, I always drop down a gear.
3. I am happy to put the foot the the floor, especially climing hills, keeping the car in a low gear and letting the engines top 5000rpm for as long is legal.

4. I also change the oil and filter every 5000 miles
5. and use Shell Optimax (Tesco petrol led to coking of the brake servo-unit).

Hope this helps
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Sat 22 Oct 2005 15:02
Volvo V40 - Weeneilly
The proof that driving style affects coking is in the MOT Hydro-Carbon readings.

The first year after I bought the car from my father the HC reading almost failed (readings over 200ppm is a fail):

47,600 miles - HC 173ppm
56,500 miles - HC 63ppm
67,200 miles - HC 0ppm (obviously a reading failure)
77,400 miles - HC 13ppm (after 8 months exclusive Optimax use)

The engine is cleaner now than it ever has been. Driving style is key.
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