VW Passat - head gasket just done - L.Cleaver1
Just picked up car (99 PD TDi Tiptronic) after head gasket replacement.....(included new cambelt, tensioner, water pump, coolant and oil/filter)

Before repair car used to accelerate quite briskly but feels very sluggish post repair. Used to be able to overtake with ease, now I wouldn't be confident to even think about overtaking!

Anyone with any ideas?

Cheers
VW Passat - head gasket just done - yorkiebar
1st port of call should be back to the repairer for their comments?

why did head gasket fail? or rather what fail was it? Combustion to water? water to oil etc?
VW Passat - head gasket just done - L.Cleaver1
Definitely contacting repairer 1st thing Tuesday morning.......shame about the bank holiday!

Combustion gas to coolant was the problem. No overheating of coolant occurred, it just sort of manifested itself over several tens of thousands of miles and eventually coolant was disappearing from overpressurisation of the expansion tank rather too quickly for my liking so thought better get it in to be sorted.

They took a photo of the gasket and a section of the third cylinder had basically been blown away.

I think the best thing is to get it back to them to test drive and as you say, get their comments.

VW Passat - head gasket just done - Hamsafar
They probably didn't do the pump timing.
VW Passat - head gasket just done - L.Cleaver1
Ashok - thanks for the suggestion. AsI'm a bit of a dumbo at this car mechanics lark....what do you mean by pump timing?

Cheers
VW Passat - head gasket just done - GregSwain
Like ignition timing on a petrol - diesel engines need to know when to squirt the fuel in (as there's no spark)...at least I think that's what he's referring to
VW Passat - head gasket just done - Hamsafar
I have never done this myself, but from things I have read, I recall that the timing needs to be checked manually, and the pulley on the pump loosened and adjusted if need be, and then once the engine is running it can be fine-tuned via a computer such as VAG COM.
I think I read it here....
www.bba-reman.com/forums/
but the site seems bust at the time of posting this!
VW Passat - head gasket just done - L.Cleaver1
Thanks for help.

The PD engine is a "unit injector" type, ie one per cylinder and presumably driven from the camshaft.....I think this is best left in the hands of the repairer who is an independent VW specialist so they should know how to do any tricks of the trade.
VW Passat - head gasket just done - Alec
On a PD the injection timing is fixed by the cam timing. There is no common injection pump.
The cam pulley is in two parts to allow it to be set dead-on when the locking tools are inplace.
If the cam timing is correct it could be the MAF, the MAP or the vacuum system that adjusts the variable vane turbo.
They may just have knocked one of the many vacuum pipes off.
The best way to findout, after checking that all the pipes have a home, is to log the engine data on a WOT run with VAGCOM.

VW Passat - head gasket just done - L.Cleaver1
Not sure what you mean by WOT or MAP

I think it has to be something the garage has done as the car flew before the fix (relative to now at least) so I hope that would rule out a sensor problem (eg MAF). I'll get them to check the vacuum pipes and if necessary run it on the diagnostic equipment they've got (presumably VAGCOM).

Thanks for all your help/suggestions - really appreciated considering this is a Saturday night

Cheers



VW Passat - head gasket just done - Alec
WOT Wide open throttle.
MAP Manifold pressure sensor.
 

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