Engine concerns

I would like to buy a Polo with the 1.4-litre 4-cyl 16v 75bhp DOHC petrol engine, preferably of the 9N3/MKIV facelift era rather than more recent. I understand that these engines can be very prone to the following issues: 1) High oil consumption and worn rings. 2) Burnt exhaust valves and valve seats. 3) Timing belt tensioner failures on the

transfer belt to the exhaust camshaft. 4) Coil-pack failures.

Is it possible to establish if or when these issues were permanently addressed (ie, from what VIN number or registration date onwards)? Are there any TSBS or recall notices and can I access them?

I believe that the engine codes affected are AHW/AXP/ALQ/APE/AUA/BCA/BBY/ BKY, but I don't know which relate to the Polo. I do seem to see more references to the BBY engine. Could it be that only the more recent Polos (MKV) are problem-free? Rob Packham

The DOHC engines fitted in the MKIV were BBZ, AUA, BBY, AUB and BKY, although the AUB is 101bhp. Addressing your question regarding the tensioner of the transfer belt, I would always change the timing belt and tensioners when buying a replacement vehicle. This will ensure you have no worries about the condition of the timing belt system.

Coil packs on all vehicles are prone to trouble, but at less than £20 each they can almost be considered a serviceable item along with the spark plugs.

This leaves your first two questions regarding the oil consumption and burnt valve problems. I can find no specific technical product information on this subject. The only info I can find that may be related is the action to take if the engine rattles after cold-starting. This makes reference to unfavourable tolerances in the engine that can lead to friction on the piston skirt.

Inspect any vehicle you wish to buy, checking the condition of the engine oil, the service history and examining the exhaust tailpipe for any signs of burning oil, which may leave a greasy deposit in the exhaust. Listen to the exhaust note when the engine is running and if you hear any popping noises from the exhaust tailpipe this will indicate the possibility of a burnt valve.