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Discussion Starter · #1 ·
04 2.5 190k.
a mechanical engineer thats very cluey on vws proposed a theory to me about our PD heads and i thought id run it by u guys and see what you thought.

for me the non start diesel in sump fix was the tandem pump. but i know that a lot of people have worn/cracked heads. i was lucky that i did not have a lot of diesel in my sump so therefore oil dilution was minimal. i just had number 1 replaced and my head and cam was all perfect.
engineer proposes that mayby the head wears BECEAUSE of diesel in sump, not the cause of it. ie, if your tandem pump is shot and causes diesel to go in sump then that could cause head wear/crack if left. once head is worn then changing pump then is too late as diesel then has another way in.
the 1 thing in common with this problem that i seem to notice is those of us with really high sump level have head problems. the starting problem but much lower sump level means head is ok.

he also believes that a faulty tandem pump could be the cause of injector number 1 failure causing shudder. a lot of people seem to have the shudder at around the same time as starting problems suggesting they could be linked. THAT link may be the tandem pump.

i wonder if the tandem pump is the horse, and the other things are the cart.

this is just a theory/idea him and i were talking about last week. can anyone blow this theory out of the water.

if we could discover/learn that the tandem pump is the cause of a lot of other problems(Achilles heel), and there is a way to prove it, then we may have an argument for vw.
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