Hello, my name is XXXXX XXXXX I will try help you with this.
I would query why the garage thought they had a problem with two injectors but the insurance company overruled that diagnosis.
I don't think it will be valve stem seals. That is something we rarely see these days.
That doesn't mean it couldn't be but it is more likely to be something else.
If I was seeing smoke and misfire when cold the first thing I would check would be the glowplugs. Especially if the fault goes away as the engine gets warmer.
Oil from a leaking valve stem seal shouldn't cause a misfire. A diesel is an oil burning engine.
I would ask the dealer if he could extend his 30 day return policy to 60 or 90 days so you can get a better idea of performance, oil consumption and if the fault gets any worse.
If he says no then return the vehicle. You have nothing to lose but he loses a sale.
As for the warranty, you should be wary. You might find a clause that will not pay for pre-existing conditions. For instance if you did require injectors at a later date then there could be an argument because the garage had thought they were suspect earlier even though the insurance company thought they were serviceable at that time.
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Am convinced myself that it is a dribbling injector after switching off overnight, garage is putting back injectors to check again, cant see the point and have said so. I dont think glow plugs come into it, engine does'nt need to warm up, smoke is gone in less than a minute and engine is smooth, it just seems to be clearing excess fuel
If you do have a dribbling injector then you will have to monitor closely the oil level in the sump. It usually causes the oil level to rise and this can lead to severe engine damage.
Modern glowplugs are not just used for starting the engine. They also afterglow for a few minutes to help reduce emissions. If one is faulty then then you can get a slight misfire until the engine gets a bit heat into it. This is why you need to have them checked.
I think I would still push the dealer to give you at least another 30 days return period to evaluate the vehicle.
You also say the garage have had the car back for a week. What exactly are they doing with it. They aren't replacing the injectors because the insurance company have said they are not faulty.
Have they found a more serious fault that is taking time to repair but don't want you to know about?