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View Full Version : 300 Tdi maintenance catch up, 2256 VNT vane problems



simmo
1st October 2019, 08:46 PM
hi guys, some maintenance catch up on the 110 wagon, shes 25 years old and done 220,000 kms, I did some preemptive maintenance as well.

new cam belt and tensioners. - the old belt was like new after 7 years, but only 40,000 k, tensioners in VGC.
new fan clutch, - the old one feels the same as the the new one.
new water pump, - the usual hassle with the long bolts being stuck took hours to get apart, glad i did it at home in my garage, at the time of my choosing. ( recommend if you are working on the front of the engine- you remove these 3 bolts one at atime and check them / grease them/replace them, use grade 8.8, M8 x 130 and hardened steel washers. the standard type are low tensile and not very good, the small heads are easy to damage.
Best to use grease or anti-sieze on all the bolts.

Went for a run up to Nambour & Noosa North shore beach, but noticed a lack of boost and high egts going up the highway, tracked it down to the variable nozzles are only traveling half the actuator stroke and don't return to the stop, so no boost down low.

Tried exercising them with air pressure many times, but no difference.
Tried water washing the turbine/ variable nozzle side side withe 7 liters of water injected into the turbo inlet side via the EGT thermo probe hole.

That reduced the variable vane actuator travel to even less, I think I washed the carbon into a place it cant get out. so the turbo will have to come off and be pulled apart. the 2256 VNT Garrett is a popular turbo so there's plenty of info on the net about pulling them down.

cheers simmo

simmo
3rd October 2019, 08:20 PM
I pulled the turbo off and after removal could see the actuator rod had vibrated loose from the adjuster, I disconnected it and the vanes could move their full stroke very easily. Then I thought I'd have a look inside, ( note to self- don't look inside VNT again!!!), the vane control part of the turbine casing was clean, but it took an hour to line up the little location pins and the vane controls & get back together. Its amazing the mass produced, stamped out precsion parts in there, they all fit together with barely a 1000 th of an inch clearance between them. I have the exhaust manifold off to change the exhaust gasket while I'm at it, its been leaking for a while. The oil return to sump supplied in the kit, never fitted well so I'm cutting it and putting a little kink in it so it lines up better with the oil return port on the engine block. Hoping to do trip to bribie island on the weekend to get some pipies and fishing. If anyone around BNE has need of a standard Tdi turbo and manifold I have three of them.

cheers simmo

simmo
8th October 2019, 08:40 PM
very happy with the Garrett 2256 VNT after 5 years. Sorted out the last of the niggly fitting problems of the kit, with the oil pipe mod & new intercooler pipe, I think it was a display model so not completely developed.
Combined with the LT230Q TC makes driving quieter and more relaxing. about 500 rpm drop in cruising RPM, and much quieter transfer case gears.