Cheap tip -- soaking VNT actuator link in WD40

[craig-pd130]

On the Passat PDs the turbo and VNT mechanism is at the front and side of the engine, exposed to road spray, salt etc that gets through the radiator. I wondered if this would cause the actuator linkage to get a bit sticky over time.

Over the weekend I got a small can of WD40 and soaked the area where the VNT actuator rod goes down to the turbo housing (engine cold) and left it overnight -- NOT spraying the actuator body (the mushroom shaped thing with the vac hose). Gave it another spray in the morning, then took it for a drive.

Got better throttle response, especially at low / medium revs. Could be worth doing once every couple of months or so .....

 

[sssstew]

yes its common for the arms to seize up so this does sound like a good bit of regular maintenance. The passats engine is mounted longitudal so it will pick up a bit more spray and stuff from the front of the engine bay, in the SEATs its at the back of the engine so a little more protected.

 

[asthpsw]

That does sound like good regular maintenance…..however as reported in a thread in the TDI section I have an immediate problem of overboost when I lift foot off throttle after WOT & I understand this is because the VNT Turbo vanes are not returning to a lesser pitch/lesser boost position.

I’ve just gone to take the engine cover off my 110bhp TDI Toledo but by doing so I can not get any additional access to the Turbo than I can from the back of the engine (down past the EGR valve area).

So what am I aiming for with the WD 40, has anyone a diagram/photo of what bit I should be spraying or this area that will ensure plenty to work its way in over night ?

Thanks

Paul

 

[craig-pd130]

You're looking for the VNT actuator valve, which is a silvery mushroom-shaped thing which has a vacuum hose going into the middle of its top. It sits just above the turbo housing.

What you need to do is use the "straw" on the WD40 can, and aim it DOWN to spray the area on the turbo housing that is below the mushroom-shaped actuator.

The aim is to get the WD40 to run down the actuator arm, and work its way into the external actuator linkage which is mounted on the turbo housing.

You do NOT want to spray UP into the actuator valve from underneath, but try to get a good soaking onto the area below the valve.

Edited to add -- have a look here:

http://www.technologie-entwicklung.de/Gasturbines/VNT15-Turbo/vnt15-turbo.html

The very first picture shows a turbo & actuator unit. The actuator is on the left of the picture. You can see a rod (with a blob of yellow paint on it) that comes from underneath the actuator, and connects to a spigot on the VNT mechanism. Its where the actuator rod meets the spigot and all that area you need to soak.

Give it a good hosing with WD (possibly when the engine is still a little warm, maybe a couple of hours after you've last driven it). Leave it overnight, then give it another hosing before you drive in the morning.

 

[asthpsw]

Craig, thanks for that, I've been out & given it a good soaking, however I'll have to improve my aim or come up with a longer straw !

Is it OK to "exercise" the actuator by pushing on the linkage on the spigot with a bit of wooden dowl, (in the direction of the "mushroom shaped thing") Is this OK while the turbo is not turning or do any damage to the vacuum unit ?

Paul

 

[craig-pd130]

You can move the linkage when the engine's not running but

1) it ONLY moves upward toward the actuator -- when the engine's off it rests at the fully extended (i.e. minimum boost) position so DON'T push it downward and

2) it only moves a short distance, literally a few millimetres so do it gently.

You're probably best giving it repeated soakings over 3-4 successive nights and letting the WD work its way around by itself than forcing it by hand ...

 

[asthpsw]

Craig,
I did as suggested & last night bathed the whole area of the VNT mechanism with WD40 (I made up a longer straw to attach to the can so I could be more accurate as to where the WD40 went to).

Took it for a WOT up the M3 & no matter how hard I tried it did not go into the “reduced power/semi limp mode” that it would do previously.
Previously WOT up a gradient on a motorway would produce an “overboost” on lifting foot off throttle, as I understand it this was due to the VNT vanes not returning quick enough to a less pitch (lesser boost).
The WD40 seems to have reduced this although I hope it is not temporary, but like you suggest I will repeat the procedure for approx 4 nights. …….Just wish it would work its way into the area on the back of the VNT Vanes.

Paul

 

[craig-pd130]

Maybe I'm being over the top suggesting every night for 3-4 nights ..... but it's probably worth doing it again after a day or so, then maybe giving it a squirt once a month.

Hope it continues to help ...

 

[SJFISHER67]

My Superb has the engine set up of the Passat, think I will have a go at this as my car sometimes develops a bit of what feels like 'stroppy turbo'

Also it 'judders' when cold and moving off at first, but not when warm, any ideas?

 

[craig-pd130]

Could also be worth checking all the little vacuum hoses that run round the engine, from the VNT and EGR etc etc and making sure all the connections are well made and airtight ..... also that none of the tubes are kinked or trapped, and that they run in smooth curves.

It's worth removing the cover over the airbox and MAF to do this (two screws) as there's loads of connectors & tubes there.

While you're in there its worth unplugging and replugging the MAF connector a few times (GENTLY), this "wipes" the metal contacts and cleans them.

 

[leon_geordie]

Hi,
I had a look last night to see what I should be spraying with my WD40 - but not really sure what to look at. Where do I stand - drivers or passenger side, and where exactly am I looking. Is it towards the bottom or top of the engine? Do I need to remove/move anything to get at it? I'm a novice when it comes to mechanics, so noddy terms are needed
Thanks
l_g.

 

[craig-pd130]

If it's a Leon, the turbo and actuator are at the back of the engine, near the cabin. Try standing on the passenger side, then follow the instructions above to find the silvery mushroom-shaped thing with the tube going into the top of it

 

[muddyboots]

If it's a Mk4 Ibiza - the actuator is below the turbo at the rear of the engine, don't know how you'd get to it, and I expect the oil would all run down the actuator arm into the actuator itself and away from the turbo.

Today is the first time I've ever been able to see my turbo - because I'd took the undertray off and was laying underneath looking up !!! Can't see it from above.

 

[TornadoRed]

Keeping your MAF sensor healthy

While you're in there its worth unplugging and replugging the MAF connector a few times (GENTLY), this "wipes" the metal contacts and cleans them.

Many tdiclub members are squirting a SMALL amount of dielectric grease in the MAF connection. This is a good preventive measure, or it may work if you're experiencing an occasional limp mode.

You can do a Google search for a list of different products that will work, but what you need will probably be available at almost any auto parts or electrical supply outlet.

There are many threads at the tdiclub that discuss the pros and cons of using dielectric grease in the connector. But here is one with some good comments.
http://forums.tdiclub.com/showflat.php?Cat=0&Board=UBB17&Number=970951

 

[craig-pd130]

Interesting .... 18 months ago I treated my MAF connector and others with Caig contact cleaner & enhancer as I'd read somewhere about the connections not being ideal. No problems yet.

 

[Fluke]

If it's a Leon, the turbo and actuator are at the back of the engine, near the cabin. Try standing on the passenger side, then follow the instructions above to find the silvery mushroom-shaped thing with the tube going into the top of it

I can't find it on mine.

And if it's where I think it is, I am going to have to remove a lot of pipe work to get anywhere near it.

Anyone help?

 

[sssstew]

yes it can be hard to get to might even need to approach from the underside removing the undertray.

 

[MAdMAtt84]

I got carried away with that site that was posted up above, reading up on the gas turbine engines that fella is making and putting into his model chopper (it was off on another part of that site) including a very good vid of the gas turbine engine running...... listen to that noise!

Muddy, so you can only see the turbo fully from underneith, seems a lil daft to me hidding it away like that. However the TDi's dont produce so much heat so i guess its not so essential for the cooling.

Being in that location does the under tray really protect it fairly well from road spray, or is it suseptable (sp?) from the wheel areas?

Matt

 

[muddyboots]

Yes it's well protected from spray etc, the undertray stops all that and TBH I think it would be OK even if the tray wasn't there - it's tucked up reasonably high behind the engine, and the inner wings will stop anything getting there from the wheels.

I don't think it was hidden away deliberately, it's more a case of there being nowhere else for it to fit - bit tight in there !

 

[MAdMAtt84]

I'd deffinatly agree with the last comment muddy. I forgot about the amount of inner wing we have, look when i made my post i was half sleep, remembering the days when i used to jet wash my mk2 polo and you used to be able to wash half the engine and watch the steam come out the front if you left it running lol.

Btw muddy, that pic may be giving me the wrong impression (40-50's ) but how old are you?....no offence ment with the first bit

Matt