2004 T5 woes .

[Sunny43.5]

Okay I am in a dilemma , our 2004 t5 2.5 Turbo diesel Tiptronic has turned into a nightmare of biblical proportions . Some of you may know of the problems I have had with regards to the auto failure but that part I hope is behind me . Ever since the auto rebuild there has been an ongoing problem . When the van is cold its very sluggish to take off , the van crawls for the first 40metres or so until it reaches around 2000rpm then it takes off like a scalded cat , then sometimes a few hundred metres up the road where it starts to climb up again the van sort of bogs down and then goes into limp mode . Now I have had it to two separate mechanics who both concurred that the issue showing up on the diagnostics were that the Turbo was overboosting . I was suspicious that the turbo was the problem all along as the last time 2 years ago I had a VW dealer service the van they told me the turbo needed to be replaced as it was leaking oil internally but now I think I am at my wits end . I recently managed to acquire a second hand turbo {Garret } from the same model van and the turbo came from a normal working engine so it was all fine , this was confirmed by the mechanic who removed it from the other van . So $2600 in costs at the second workshop and the van is exactly the same still , exactly the same take off problem maybe marginally quicker but still displays the same limp mode problem . I can drive onto a flat piece of highway and accelerate up to 100 kmh the van seems to change gears going up to 6th normally , then whilst coasting at that speed I can try to accelerate to a higher speed and the van just slows down with no acceleration until it struggles to make forward motion and attempts to downshift with eventually going into limp mode again . A simple switch off and restart and its fine again . Now I know a box of matches would fix the problem but I was hoping to sell the van as its a bloody good looking vehicle with loads of extras and only 150000 kays etc , but I will not be happy trying to sell it the way it is . I would welcome any suggestions .

[Umai Naa!!]

Interesting that it's logged an overboost code, when from your description of the symptoms, it sounds like it's running less boost.

Overboost codes are usually related to sticky vanes in the back of the turbo, faulty N75 boost control solenoid, and the MAP sensor in the intercooler piping under the coolant bottle.

Have heard of a few people sorting out the sticky vanes with some oven cleaner sprayed in the back of the turbo once the down-pipe is removed, and working the actuator rod. Can't really recommend this, as I've not tried it. The other two are simple swap-outs, and the parts should be easy to source at a reasonable price off eBay, etc.

[Sunny43.5]

Thanks Umai I will wait a few more days to gather other ideas , it's just P'ing me off as every time I get close to having it ready for sale something keeps cropping up . The sticky vanes were mentioned in conversations so I would imagine the people who fitted the turbo would have at least cleaned and or checked that before fitting it as they did do a complete oil and filter change gaskets etc .

[Tig-uan]

Instead of selling the van privately, trade it in for a T6. (I had a similar situation with a Tiguan which had grinding noise from its manual gearbox and VW would not fix under warranty as this was pronounced a comfort-issue. Rather than upsetting a buyer after a private sale, back to VW it went as a trade-in, in fact, I got a better trade in price on it than was offered privately.)

[Umai Naa!!]

T6 is sti a while off yet.

[Sunny43.5]

I tried to trade it two years ago on a new T5.1 the damn dealer was an ******* . When he found out it was an automatic he said they would not trust it and offered us between $4000 and $8000 as a trade , ahem so our $52000 original purchased van was then worth only that much even though it was a one owner and at the time 130000 kays with service history , I stormed out after that .

[Sunny43.5]

Well it is Good Friday and after two years of searching for a solution it seems today was my day . As I posted a week ago the wifes 2004 2.5 T5 was in for a replacement Turbo as it had been getting slow to respond and causing the van to go into limp mode . Well after the $2600 plus at the workshop who said they would diagnose and check and then report on the Turbo it seems they are a pack of useless idiots . Yes I will use that term because as it transpires today I found out the problem . Thanks in part to Umai who started me of on a path to discovery , the workshop fitted the turbo and they got their money . Less than a kilometre from them I realised something was still not right , the van displayed all the same symptoms limp modes and sluggish performance with erratic gear changes . So today I am under the bonnet with the engine running checking the locations of the N75 solenoid and MAP sensor as Umai had suggested might be the problem . Well I may be partly deaf {loud music will do that you know } but I could here a strange hissing sort of sound , well I listened and zoomed in on the vacumm pipe which feeds the brake booster and in turn feeds the various valves and solenoids etc . Right at the point where the tube leads off the main line the tube to the solenoids etc was split . I could feel around the tube and hear the sound change , so on turning it over I could see a split where the tube was fitted over the outlet pipe . So I cut off the small section refit the tube and now the van has been transformed !! No more lag no more erratic gear changes and no more limp modes . So 20mm of tubing has cost me $2600 does anyone think these guys should have picked this up ?? I will be on their door step on Tuesday for a Pauline Hanson moment .

[fransnz]

Hey Sunny

Glad you finally found the fault. I had a similar problem a few years back with a golf tdi where a plug was put back the wrong way after a cambelt change at vw and the car kept reading over boost and going into limp mode.
Changed the turbo and still had the problem till i had a good look around and found the plug.
I know your pain.

[Sunny43.5]

Thanks Fransnz , this a huge relief for me as this van has been a money pit with Auto failure adding to the long list of needless expenses . The over boost did seem strange on the code readings but thinking back it would have read that as the turbo could not get enough vacuum when it was needed . Then because the auto was changing erratically because of the slow spooling the turbo would have been out of sync with engine revs etc . I could not believe the difference after doing the repair the first time I took off from out of our driveway uphill the old girl gave a familiar squeal from the front tyres as it struggled for grip with all the good old power back on tap , gear changes were so much better as well as they had been very erratic as well . But now they change when they are supposed to , on a flat road at around 80kays it will shift down and take off smoothly changing up rapidly as the speedo races past the 100kay mark .

[grtuned]

This is probably a lesson for many owners of a Vw
You cannot always go to a mechanic and have him try repair a vehicle if they have no clue in diagnosing an issue and without any VW experience you will be up for a ridiculous amount of money spent without fixing the issue. I'd be buying a box of beer for umai
as for the clowns who missed something so simple Id have a good talking to them. how on earth were you given this car back after a turbo replacement with the same issue. Did they even road test it and realize the issue was still there? People like that piss me off it makes all mechanics seem like rorters.