Coking - today's DT

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Sat 23 Feb 2002 14:39
Coking - today's DT - Tom S-S
Read with interest the letter in today's DT, about coking of engine. I had a problem with my Subaru chuffing out a cloud of smoke when changing up under hard acceleration. Various on the backroom suggested worn valve stem seals. However haven't used anything to cure/prevent apart from using only Shell petrol, this has cured the problem, interestingly filled up with supermarket fuel the other day (as nearly ran out couldn't make to a Shell station) and occasionally would have smoke behind when changing up.

Can I use Shell Optimax in my 1990 Subaru Justy GLII 4wd 1189 cc (carbed model) or will it be bad for it/a waste of money?
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Sat 23 Feb 2002 16:18
Re: Coking - today's DT - Honest John
Waste of money. But do use a 95Ron with decent detergent such as Shell Premium Unleaded or Texaco.

HJ
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Sat 23 Feb 2002 18:38
Re: Coking - today's DT - Mike Harvey
Tom, I'd have thought it unlikely a valve stem seal problem, as that is a start up or over-run problem when oil either drains down the inlet valve guides when parked, or is 'sucked' down when inlet manifold depression is high, and then gets burned. Much more likely bore/piston/ring wear. I would also have thought it must be fairly bad, as you can hardly notice smoke when you are driving, but following an oil burner is a different matter!
Best regards,
Mike
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Sun 24 Feb 2002 20:52
Re: Coking - today's DT - chris
H.J. always says stay clear of supermarket fuels (despite their claims of detergent additives) and recommends Shell or Texaco, what about Esso because the garage is just down the road and there is 60p per £20 off!!?
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