Recently, a Volkswagen Touran 1.4TSI came to us with the engine malfunction indicator light on. We were told it is a notoriously troublesome engine, and “don’t touch with a barge pole”. But undeterred, and with our Volkswagen premium grade diagnostics, we were ready for the challenge and well placed to investigate such a fault.
This particular fault related to the variable valve timing solenoid being out of range and camshaft/crankshaft correlation, which is a good indication that the valve timing had become out of sync. We could (and many garages do) just rely on those fault codes and go ahead, all guns blazing, and start ripping the car apart, but we never like to rely solely on a diagnostic report. We believe it’s best practice to confirm the fault before informing the customer or pricing up the job.
Technicians who replace parts purely on what the diagnostic machine tells them are playing a risky and potentially costly game (a cost usually passed on to the customer). Diagnostic fault codes are quite often symptoms of a fault not the cause. The engine’s on board computer can only tell you what it is detecting, it can’t always determine between a faulty component or a wiring fault, for example.
To confirm our diagnostic suspicions, we needed to check the valve timing was indeed correct. A quick performance check of the sensors proved they were doing their job correctly, but did reveal that the crankshaft and the camshaft were not sufficiently aligned. So, electrically everything was working correctly, therefore it must be a mechanical fault. Proving the sensors are working but the position of the cam/crankshaft was out, is proof enough that the timing needed to be corrected.
It is at this point we are 100% sure of what the fault is and can accurately price the repair and inform our Client. We never do any work without our Client giving us the green light, and go to great lengths to ensure the Client is fully aware of; what the problem is, what we are going to do to fix it, and crucially how much it is going to cost.
Once we had the all clear it was time to set about the repair. The first job was to remove the offside front wheel, plastic inner arch lining, engine sump, auxiliary belt, water pump and suspend the engine to remove an engine mounting. Once these things had been done we could then remove the timing chain cover to reveal the faulty timing chain assembly. Visually it looked like everything was ok but after trying to lock the engine in its service position it became clear what had happened. After getting cylinder 1 piston at top dead centre (TDC) a locking plate should be able to be inserted into the back of the camshafts, however the inlet camshaft was nowhere near where it should be. After replacing the pulleys, guides, chain tensioner and the chain itself, we could correctly time/lock the engine in position and tighten everything up. As a safety precaution, we manually turned the engine over a couple of times and re-checked the locking position ensuring everything was synced correctly, and thankfully it was.
All that was left to do was bolt the car back together, refill with new Shell lubricants and start the engine. Starting the engine for the first time is always a nervous moment but this time the engine fired into life instantly and the malfunction light was no longer illuminated on the dashboard. Before the car was handed back to the customer it under went several road tests and diagnostic scans to ensure everything was ok. We even gave the car a thorough wash. Another good day’s work! Find out more about us at www.okeedrive.co.uk
Editorial from Mark Lawson, Operations Director at Okee Ltd
Ben Grave, Mark Lawson