Thanks for your suggestion. How would I know it is the timing chain as opposed to the cylinder head?

I've also only done just shy of 40k miles, I'm not sure what the service interval is for timing belt but wouldn't this be unlikely?

Any info on what tests the garage has done to come to the conclusion of "the cylinder head" ? It seems a bit of a vague diagnosis, especially since they aren't 100% sure that's the cause. If it's the head gasket failing there should be some indication by way of coolant loss or overheating. Plus the compression test you had done should have shown if 1 or more cylinders was down by leakage from either a valve, piston ring or cracked/warped cylinder head.

The throttle body problem I suggested usually only manifests itself on idle and at low driving RPM but the car performs OK at higher speeds so it could still be the issue. If the battery was disconnected or run flat whilst the car was laid up SORN'd, the throttle body can lose it's basic settings and the fuel can "go off" whilst standing causing gummy deposits to build up in it along with the filter and injectors which you say have made an improvement since replacement.

The "kiss of death" timing chain issue that was brought up does not apply to this engine as it is belt driven ( two belts actually) and if either has jumped a tooth or two, would effect the running throughout the whole rev range, not just idling. From memory, the scheduled replacement for the belt kit is 80k miles OR 4 years and from my own experience, changing the coolant pump is a must.

I'd be inclined to get a second opinion from a different garage before handing over all that money for what basically equates to a guess.

Edited by The-Mechanic on 18/11/2013 at 20:35

Thanks for your advice, will keep this in mind.

Before throwing loads of uneccessary money at this,has anyone suggested that the engine may not be filled with the correct spec oil.Perhaps the oil and filter should be changed before anything else expensive is done, along with the fuel filter.Worth a shot.

Right, get the fuel filter changed and the spark plugs and air filter next then that'll rule out them as the culprits. The garage that said if there's no running problems at higher revs in regard to the throttle body obviously don't know what they are on about. I've been working exclusively on VW's for about 8 years now, and in that time all the 1.4 and 1.6 engined cars that were diagnosed with throttle body issues had idling problems but were OK once driven over about 1500rpm. Also, it's worth looking for any air leaks on the intake system. The favourite is the vacuum hose to the brake servo from the inlet manifold. The plastic pipe goes brittle and cracks/splits around the elbow joints and can cause idling issues as unmetered air is being drawn in weakening the mixture.

Find another garage to carry out diagnosis if changing the remaining filters and plugs doesn't help as the one you have gone to only seem interested in taking your money off you and not carrying out a proper and full diagnosis. I can't see what the problem is with not cleaning and re setting the throttle body ? It's a simple and cheap job to do rather than replace/repair a cylinder head that in my opinion, is not an issue in your case. Anyways, if the head is removed, the basic settings need to be done as a matter of course cos the throttle body has to be disconnected.

Hello

Quick update......I have taken the car to a new garage and they have redone the compression test.

The invoice says 'carried out compression test, low on all cylinders but lower on 1 and 2. Suspect valves fractured and recommend replacement' I haven't the exact readings, sorry I forgot to ask.

They've told me this costs around £750.

I asked about the other tests initially but they just did the compression test again. On discussing this they said they felt that the valves were most likely the problem here. They didn't do a leakage test even though I'd suggested this or a balance test.

Is there anything else that can be done to salvage the situation rather than having this major work? This place was an independent VW garage and thinking might have to escalate it to the main dealers.

Edited by adidas on 12/12/2013 at 16:26

Like skidpan says, it decision time....

If two cylinders are down on compression then the likely culprits would be the valves being burnt out. I've seen this many times on the 3 cyl 1.2 engines, not so much on the 1.4's but having said that, it'll make sense seeing as the car was laid up SORN for a while, the valves may have not so much stuck open, as has been mentioned in an earlier post, but not being able to fully close, causing the hot exhaust gasses to slowly burn the seats over time. Once this happens the only course of action is strip down, repair or replace I'm afraid.

One final, last ditch attempt would be to check the valve timing. If it's slipped there's the possibility that the valve overlap could cause low compression as they may not be fully closed on the compression stroke, but that's really clutching at straws. Also, if that's the case, the valve seats will be burnt by now anyways.

As I see it, you have 3 choices :

get it repaired ( not a nice financial thought this close to Christmas )

SORN it till you can afford to repair it

sell it for spares/repair