9 replies to this topic

[mathomas3]

Hello all...

 

need some advice... Im having issues with the turbo...

 

When the engine is cold the turbo works great... but once it does warm up the turbo looses boost at the 2500 rpm Range... but it still works in the lower range... just when the engine is warmed up do i lose boost past 2.5k... I had a look at the turbo and also a Mech and i was told that it's only got 25% life left in it... and i have no check engine lights...

 

i have searched google and there is a wide range of people talking about sensors... and some are saying that the veriable splines in the turbo might be gummed up... (which i would think would cause it to be gummed up all the time and not just when warm...)

 

so i thought that i would ask you guys here and get your thoughts...

 

Thanks...

 

Mat

[IainStallard]

Any smoke at all? If a turbo is on its way out, then get it checked as soon as possible. If the turbo disintegrates then all the debris will makes its way into the engine, and if an oil seal goes, then the car will run on its own oil, causing it to starve itself.

Engine check lights will not light up if a turbo is on its way out.

Sounds like some things amiss. When our vans turbo was on its way out, it had the same symptoms. This was because once the turbo had warmed up, the insides practically locked up, meaning it wouldn't spin up.

[mathomas3]

im not getting any smoke... and when we pulled off the air duct to the turbo they said that there was some play but not enough for it to be ruled as the cause... but then again they didnt rule it out...

 

i would like to avoid buying a turbo needlessly... so if there are some sensors that you think would make sense to replace please chime in...

 

im hoping to get a pool of knowedge here...

[Carlos W]

As above, if the oil seal goes the engine starts burning it as fuel and it's very difficult to stop!

 

Is there any oil between the turbo and intercooler in the air duct?

 

did the turbo spin freely enough when you took the air duct off?

[mathomas3]

it spun free...

 

and there wasnt any oil in the air duct...

[sonikk4]

How many miles has the engine got on it???? Have you checked the MAF, the N75 valve which helps to control the wastegate actuator etc. also at the back of the engine bay are some very small bore air pipes all do with vacuum. Any of these can cause your problem.

If you do not have a warning light this does not mean there is not an issue. Get a code read done first before you go ripping into things.

Now this website is not the place you need to look at, go to this forum I am a member off www.vwaudiforum.co.uk.

Ask for crasher and he will be able to help as he is a guru at all things VW. ( he's the one with 20,000 odd posts)

Going back to the turbo if you do get play and its quite significant then the Turbo is on the way out. Yes the vanes do get gummed up and there is a thread on the forum with regards to this and how to clean them.

Oh and I have owned two of these beasties with no issues with regards to the turbo etc, and I have clocked up over 130,000 plus miles in both of them.

The other thing to look at is the inter cooler pipe work. See if this is damaged at all. Don't be worried if you see a little oil around the bottom pipe both mine had it and I have seen this on quite a few others.

[wolfie]

I would also say MAF

Unplug it and drive around the block see if it makes a difference, egr valves also clog up but can be taken off and cleaned with carb cleaner

[ANON]

possibly map sensor, worth giving it a quick clean. get a smoke pressure test done to look for boost leaks, any signs of oil under the intercooler?

[ejs-1995]

N75 valve common on passat tdi's I believe. Also, vanes in the turbo can clogg up causing over/underboost

[MBarnes]

Is the turbo excessively noisy? As the fault is temperature related, i'd probably be checking the things that can be affected by temperature - see if you can a mini-vacuum pump on the wastegate (obviously be careful when its hot) to check its operation.

 

Matt

 

Edit: As said, it'd be worth getting the fault memory checked for overboost/underboost faults and for any other faults relating to the N75 solenoid valve and MAP sensor

Edited by MBarnes, 27 July 2013 - 10:17 AM.