View Full Version : Turbo help!

02-17-2007, 02:20 PM
OK guys, I need a hand. A while back I lost boost on my stock '99 A4 1.8t with 125k on it. Other than being slow as hell it runs fine, so I haven't done anything about it until recently. It's getting the same MPG, no knocks, whines or new noises, no codes on VAGCOM. The boost gauge shows vacuum, but even under wide open throttle it goes right up to under "0" and stays there. I checked for vacuum leaks and found that the PCV tube that goes into the crankcase under the intake was cracked so I replaced that and the vacuum line that goes from the front of the intake to the diverter valve since it had a small crack in it. I replaced the diverter valve with the 710N and replaced the N75. I figured that even if they weren't an issue that it was time to put in new parts. After all that I'm still in the same place so as far as I can tell that leaves either the turbo itself or the wastegate. Since I don't hear any nasty sounds or see a bunch of smoke I figure it's the wastegate actuator. Now I always thought it worked on vacuum but when I applied up to 25 in. hg to the line that goes from the N75 to the wastegate actuator, the arm didn't go anywhere. So I turned down the regulator on my air compressor to 15 psi and hooked it up to the same line. This time the arm moved back towards the turbo and returned to it's original position when I removed the compressed air. Anyways, if anybody's still reading this, I could really use some advice. What's going on here?@!? [headbang]

02-17-2007, 03:39 PM
The turbo isnt vacuum powered, its exhaust powered and vacuum regulated

Thats the wastegate... it opens during boost,.... you proved that it works I would pull the induction hose off the front of the turbo and see if the impeller is locked-up first, it should turn smoothly and freely

Does your A4 smoke?

If you want to buy another K03 let me know, mine will comming off real soon 40k doesnt use any oil, only been boosting over .6 bar for two months

02-17-2007, 04:35 PM
No, no smoke. If the turbo wasn't spinning properly wouldn't it be making some serious noise? I was thinking maybe the wastegate was stuck open so none of the boost was making it to the intake...

02-17-2007, 06:12 PM
The wastegate accuator and rod are moving so, its probly not suck, but to accually check the turbo out completly you'll have to remove it. But to check to see if the impeller shaft is locked up its just one hose clamp, once you've got the air intake routing duct work out of the way, if it spins... then I would move to the next step...
and remove the cat, and see if the exhaust impeller is even still intact, if it is then I would remove the turbo because the wastegate is internal

02-17-2007, 06:26 PM
That makes sense. Thanks for the input, I'll let you know how it goes!

02-18-2007, 11:33 PM
keep us posted

02-19-2007, 07:40 AM
shot wastegate actuator

Very common happening happened to mine, and gave me an excuse to go K04

options are to get another wastegate and install it, but its easier and cheap enough to just get another K03

02-19-2007, 05:00 PM
OK, so here's the latest...
I pulled the intake hose off the front of the turbo as superman_006 suggested, and I took some great pics but I can't figure out how to post them here. Any help on that would be appreciated because seeing is believing. At any rate, it's coated in grime. At first I could spin the impeller by hand and while it didn't spin freely, it would spin. There wasn't really any play in the bearing, but it was as if the fins were catching on the housing. it would spin like 1/4 revolution and then stop because it caught on something. It looks like the turbo is shot so I'm surprised it isn't making any nasty noises. My question is, where is this sludge coming from? This is the intake side, so it should be clean, right? I don't want to replace the turbo just to have it die prematurely from the grime.

02-19-2007, 05:06 PM
If you go to
www.photobucket.com and sign-up for an account (its free) you can upload the pics then just click on the button that says "copy" under the pic after you upload it. Then just right click here in your text and paste, it will paste it in html codeing

The oil came from the turbo oil seals, I'm surprized it wasnt smoking
And if you repalce your turbo you can clean out your intercooling and piping with cemicals or gas (not sure which one would be cheapest)
There are a few turbos for sale in the classifed section

02-19-2007, 05:21 PM
Umm howcome noone uses audizine picture poster?

if you dont know how to use photobucket or know about it then just go to gallery in your top right corner and upload pics

about the "grime" Dont worry about it, your not the only one unless the oil is fresh, and then thats a problem

02-19-2007, 05:23 PM
My bad.... I didnt know audizine had one

02-19-2007, 05:25 PM
yeah I always wondered that too

02-21-2007, 04:51 AM
well, I already had a kodakgallery.com account, let me know if this works...


02-21-2007, 04:57 AM
It's not like the sludge is so thick that I think that's what caused the problem, it just looks like one more issue. The fact that when spun by hand the impeller is catching on something that makes me think it's shot.

02-21-2007, 04:37 PM
I cant see the photo, I clicked on the link and it wants me to sign up

02-21-2007, 06:39 PM
try photobucket. easy sign up.

02-22-2007, 10:47 AM


02-22-2007, 11:28 AM
I would say thats pretty wore out, the shaft bushing is so wore out that the impeler has worn the housing

02-22-2007, 11:34 AM
yeah id say it looks pretty shot to me, i have a k03 for you thats in excellent condition.....just make an offer, and its yours.......you can PM me, call me 31551596610, or aol me....vaccaman11