Engine failure

Q

Was wondering if you might be able to help – initially to advise if we are reasonable to consider that there is evidence of piston/valve contact, and that there would be a robust case to take action against the garage. My friends 60,000-mile Jaguar XF 2.2 diesel has run smoothly with no issues for the last six years. The vehicle was serviced, MOT’D and had a new timing belt fitted at the garage. He then drove five miles home.

The next day, the engine was difficult to start, and the engine sounded noisy – even his wife commented.

He took the Jaguar back to the garage and they kept it overnight – they acknowledged the starting issue but said “there was no cause for concern – book it in next week”.

The next day, it was again hard to start – he drove a further three miles and car broke down at 70mph on cruise control. The AA say fault code P0341 Camshaft Position Sensor A (bank 1).

With the vehicle back at the garage, they reported six exhaust rockers broken on cylinders 1 to 3, but claim timing belt and tensioner correctly fitted so it is a pure co-incidence this has happened within 45 miles of timing belt change!

Their report:

“We have stripped and investigated the vehicle, and can now see that the timing is in fact correct. We removed the rocker cover and found several of the rocker arms broken (this was giving the false impression of the timing being out). We removed all four injectors and found that Injector #4 was extremely dry and corroded – this is clearly evident when sat next to the other three. My Jaguar Master Technician has suggested that Injector #4 has failed, causing the other three to over compensate, allowing the engine to ‘hydrau-lock’ thus causing the rocker arms to break!”

However, even after the injectors were all bench-tested and passed, they are still sticking to the over injection of fuel theory, apparently because the three bores where the valves failed are wet with diesel – they say that proves it was over-fuelled. It seems to me that these bores would be wet because the AA and the garage both tried to start the car, so while it is cranking over, fuel is being injected and since the exhaust valves are not opening on three cylinders, there is nowhere for the fuel to go!

Also, the injection system passed an MOT emissions test, 45 miles earlier and the injectors were subsequently proved not to be faulty. There was no smoke noticed from the exhaust (checked mirror as soon as the car started to slow down, when the engine failed on a busy dual carriageway) and there were no fault codes for the CPU or the injectors, as per the AA report.

This whole theory sounds implausible to me. With a stationary engine I would expect fuel build-up could cause hydro lock when turned on the starter, but how could enough fuel suddenly, for no apparent reason be injected into 3 of the 4 bores to cause this while the engine is running at 1800rpm, with 900 exhaust strokes per minute. They cannot give me a good explanation of how this is possible, other than three of the bores were wet.

Incidentally, it was the same ‘Master tech’ who advised there was “no cause for concern” eight miles before breakdown, who verified that the timing belt and tensioner were correctly fitted!

His statement is the only evidence anyone has that the belt and tensioner were fitted correctly.

The garage took off the head, and to me, there is evidence of valve piston contact with clear valve imprints as per the photos enclosed but they refuse to acknowledge that.

The valve face is perpendicular to the piston.

Extract from their latest email below

“We see no evidence of contact, both physically and in the

photographs. Furthermore, as discussed below if there was contact at all, but more specifically contact enough to break rocker arms, then we would be expecting to see major marks on valves – there are none whatsoever. For the purpose of clarity, our stance will remain the same and final, that no contact/interference has occurred between the valves and pistons.”

We would appreciate your opinion, since they expect my friend to foot a large engine rebuild cost, 45 miles after paying them

£2k for a service, MOT and timing belt change – ironically as a precaution to guarantee reliability.

I believe the service manager and the ‘master tech’ are spinning us a cock and bull story, and no one I have spoken to considers the over-fuelling theory to be even possible. But they are sticking to their guns. This has been dragging on now for some months and my friend is becoming very anxious.

Alistair Bell

A

My first comment would be that the fuel on the pistons could not be from an injection fault, as any such fault which left that quantity of fuel in the bore would have been creating copious amounts of smoke from the exhaust, and as the cylinders would not have been firing the engine would have a very serious misfire.

Even the slightest action of combustion in the cylinder would have cleared the excess diesel from the bore. Add to this

that the vehicle has just passed the MOT and the associated emissions test, then any failure of the injection system does appear to be very unlikely.

The DPF regeneration is initiated by indirectly injecting diesel fuel, and it is possible that this system failed, but this would again have caused smoke to be emitted from the exhaust.

Another point to make is that an engine hydraulically-locking up at 70mph would almost certainly cause a conrod to bend and would be more likely to cause trouble in that area than it would to cause the rockers to fail.

I will admit that having worked in the trade for many years, I have seen problems which have occurred as a coincidence, and this can be simply due to the slight disturbance which then manifests and is totally unavoidable.

But the fact that the vehicle was returned for inspection and that it was advised by the garage that the vehicle was safe to use, does in my mind imply that they do have liability in the matter.

One consideration is that although the AJI4D engine uses a timing belt, it does also have a chain between the camshafts, and it has not been mentioned if this has been inspected. It could be the case that the chain has stretched and is the cause of the failure. This may be associated with the P0341 code read by the AA.

One point that is concerning me is that on one of the pictures it would appear that a small section of the piston has broken away.

If the garage are a member of any trade association such as the The Motor Ombudsman or the Retail Motor Industry Federation, or an alternative dispute resolution (ADR) scheme then I would first contact them to voice your concerns. Any connection with such an association should be clearly displayed on their paperwork and website.

Given the garages reluctance to accept any form of liability for the problem I would suggest that the only way forward would be to begin action and contacting trading standards may be a good move. The first stage of this would involve an engineers report which would normally cost around £180. Any court action will require such a report and it may be the case that given the scrutiny the garage may alter their stance on the matter.

www.scotiavehicleinspection.com are a reputable company who could carry-out such a detailed inspection and compile the needed report.