MOT gone wrong - Advice please
 

Hi all,

I have owned my 2.8 QS for a year and a half now and it has been superb,very few issues even at 101k. MOT time so booked it in, new rear discs/pads as expected but I also got the mechanic to do an engine oil/filter change.

Picked car up everything seemed fine, drove to a meeting 60miles away, as I was pulling in to meeting car park steam started pouring out of engine bay. Had a look, coolant everywhere. Went into meeting, came back out, called mechanic, he said keep checking coolant level and try to get back to garage. 5 miles down the road, coolant temp went to 120c+ so pulled over on hard shoulder and got breakdown truck to take me back to garage. Whilst waiting for pickup I noticed one of the rubber radiator pipes (next to oil filter) had moved slightly somehow and had been rubbing up against fan belt pulley wheel which must have caused coolant leak once it wore through.

Anyway over the weekend mechanic replaced rubber pipe and topped up with coolant, then came to pick me up last night so I could drop him off, pretty much as soon as I started driving it became very lumpy, rough idle, very tractor like. Pulled into service station, radiator top up tank was boiling and took quite some time to open and top up. we suspected vapour lock so bled out some air using the two screw/nipples at back of engine bay, topped up with water and carried on. He said it wasnt lumpy when he set off but that I should leave it over night to see if lumpy in the morning (if it wasnt lumpy on cold startup he suspected it may be spark plugs). This morning, even worse, struggled to get to work and had to abandon it at side of the road. sounds like its running on 4-5 cylinders, alot of vibration esp at low revs/idle, mechanical tapping noise when reving past 2k, down on alot of power, stalled on slight hill on way to work and doesnt have enough power to move forwards. no real smoke that I could see but could smell hot oil from engine bay.

So, any idea what is going on? Have I cooked my engine? Has he cooked my engine by setting off to pick me up with vapour locked radiator? Was it vapour locked? Whats the mechanical tapping noise?

Mechanic is coming to pick it up a third time later to see if he can identify the issue. Im preparing myself for the worst though as if this is a new engine required I may have to get rid of the car.

Thanks in advance :)

Sorry to hear all that. It doesnt sound good and in attempting to drive back to the garage (first piece of bad advice from mechanic methinks) you have done more damage. The symptoms are that of cylinder head/liner damage. Is the water contaminated with oil or vice versa?
:-(

Always looking to be optimistic, are a couple of the coil packs likely to have fried? Get it on VagCom if you can.

Always best to be optimistic laird, the V6 only has 1 big coil right at the front above and behind the fan, not individual coils, when they die they usually die in 2's so it'll drop to 4 and run (reasonably smoothly with a few revs on but at low revs, lumpy) with a loss of power and as the cats get a free unleaded bath (which does them no favours) smells most unpleasant. Doesn't account for the boiling coolant bottle though? Hopefully just the coil........

Thanks for the replies guys, I'm very much hoping (fellow optimist) its plugs or coils but if it's more serious is it worth fixing head liner damage or would it be best trying to source a doner engine? Bare in mind I just had timing belt done 5k ago plus temp sensors.

Will get news tomorrow once it's been examined. One thing mechanic did say is that he appeared to be imparting blame a little on the fact that rad pipe in question appears to have swollen prior to contact with belt pulley, mentioned engine may have had some contamination in water of some form that caused pipe to balloon. I have a photo I took whilst waiting for pickup down into engine bay if anyone's interested showing the contact between pipe and pulley.

Either way it doesn't get round the fact I probably should have not driven it one inch once I'd noticed high temps:(

It does not sound good. My friend did similar thing on older C4 A6 with 12v 2.8. Lost coolant, kept driving, overcooked engine, oil burned on in heads blocked oil channels and stopped supplying oil to camshafts which started seizing up from running dry, cambelt jumped couple of teeth because of extra resistance on camshafts. Engine gradually started running worse until stopped at the end. Engine was a scrap and all that in 2 about 2 miles.

Hope you have better luck.

Mine was missing the mounting for the hose so it was rubbing on the fan without me knowing, then suddenly burst in to steam one day. Had a quick look to asses damage, filled with water from the nearby tyre garage, took off the expansion tank cap to prevent from pressure building up and pushing water out through the hole in hose and took extra 2l water bottle with me to fill up on the way. Drove about 15 miles home taking it easy, barely lost any water and did not need to fill up on the way and no other damage to car.

Ok got a text from mechanic last night saying lost compression on cylinder 2 and low compression on cylinder 5. Doesnt sound good to me, is this worth fixing or am I looking at new engine/car ? Any key questions to ask him?

Id just like to have as much information to hand for when I speak to him later.

Thanks for the help guys!

If you're lucky, it might just be a blown head gasket (or both head gaskets as it's cylinders 2 and 5). Ask if there's any oil in the water/water in the oil as this might support this theory. And ask their thoughts as well.

Then, depending on how 'cooperative' the garage might be, I'd asked them to remove the heads, check the gaskets and check for any warping of the heads/blocks. And see if you can agree a deal for this (preferably FOC) as I'd suspect thae garage has caused this problem, even if only by advising you to continue driving the car on 2 occasions!

Once the heads are off, they should be able to see the extent of the damage and advise you on the prognosis.

Fingers crossed for you!

Phoned mechanic today to go over the options, of which I basically have three i think. he didnt spot any oil/water mixed so far.

1. Get the engine repaired, mechanic says if any valves knackered all will need replaced. Could be messy and no idea how costly

2. Get a second hand engine and have that fitted, mechanic found one with 69k on for about £450 and then said it would be about the same again to fit it. He did say he would ensure the timing was done for me on this new engine though. max price £900-£1000

3. Get another audi a8 and use my current car as a donor car, have plenty of drive way space, would mean cheap/free spares for a while but another a8 may come with its own load of problems. price £2.5-5k

Im leaning towards option 2 but if anybody knows any better do please let me know, its probably the least expensive way out of this and will mean my new rear brakes will get some use.

Sorry to hear of your woes.....

Heres my thoughts....

The 2.8 QS is a rare car. It doesnt really have the max economy of the 2.8 as it has the quattro drag, and doesnt have the 'thrill' of the 4.2 as it doesnt have the grunt.... Its a fine car, but quite niche.

Unless you are constrained by insurance cost, or a burning need for literally only a handful more MPG, you may take option 3 but consider using it to upgrade to the 4.2 A8 ?

Ploughing a grand into a car thats worth only a few doesnt sound a great investment, and worst still it seems the car was fine till this garage serviced it. If they can't put the coolant pipe back properly, whats the odds of them changing the engine sucessfully ?.... You're also putting a lot of faith in the 2nd hand engine originating from a good, well serviced car.....69K sounds great, but if its low miles because its done them all 5 miles at a time with cold oil, its not going to be as good as it sounds.....