polo wastegate rattle noise

[bn1986]

blast from the past...

my car has been making a noise like a cicada for the last 15,000k's - I finally thought about doing something to see what's doing it and disconnected the N75 today on the way home from work, noise went away.. I assume it's doing what Sean describes here

is it just annoying or is it doing damage to something?

Hey guys - just got notification in my spam folder about ppl digging up my old post.

The polo is long gone - driving a forester these days!

However - i never posted what the end outcome of all this was.

- Mechanic pulled the turbo off, and found a cracked exhaust housing.

Replaced the turbo, problem solved.

Im sure its not what you wanted to hear, but figure i'd give some closure on the matter.

the mechanic also installed the forge wastegate actuator - despite my asking him not to, and of course didnt tension the wastegate actuator correctly.

hope it doesnt turn out to be the housing as it was in my case.

Ben

[simon k]

- Mechanic pulled the turbo off, and found a cracked exhaust housing.

Replaced the turbo, problem solved.

hope it doesnt turn out to be the housing as it was in my case.

Thanks for getting back to me.. This is actually my suspicion, I've checked everything else. Sam gave me another turbo housing but there are cracks in that too.

I nearly took the manifold off the other day to see if there was a leak at the exhaust manifold.. I'm glad I didn't because I won't want to put a badly damaged turbo housing back on

[h100vw]

Have you got pictures of the cracks Simon? If you do go for a turbo swap, port that stock manifold for some free power and torque. I just did mine and it's a load better than the 034 I took off

[simon k]

Here's the crack, looks like a manufacturing flaw that's opened up a crack. I wouldn't expect it to last long on a motor




I ported the exhaust manifold a bit when I had it off a while ago

[h100vw]

Doesn't look so bad. Buzz a grinder down the crack and MIG it back together. Lol

[simon k]

There are a couple of fine ones down the inlet throat too

[simon k]

this is a new replacement housing, the seller says it's the right one... K03S Turbo Turbocharger Turbine CHRA Wastegate Exhaust Housing 1.8 20V 180BHP | eBay

[sambb]

I only just got rid of my good exhaust housing. Bugger. The sealing surface is on the flat part there so if the crack hasnt or wont run up onto the flat it'll be ok. But having said that, yeah I probably wouldnt throw it in given how involved a turbo swap is on this car. I've now had 4 x K03s's apart and they have all had cracks in the hot side - mostly in the lip below where the crack is in the pick, but also up on there too. Two of those ran without any dramas, so my guess is it be ok.
The other thing you could do is undo the 3 turbo to exhaust mani bolts and the bottom bracket for the turbo. That'll let it drop down away from the exhasut mani and then you can get access to all the exhaust mani nuts to check that they are all tight. Then its just a turbo to exhaust mani gasket and retighten the turbo bolts - still a poo fight but no biggy to ensure that its not the exhaust manifold to head connection thats leaking.

[simon k]

That's what I did on the weekend, I didn't go as far as dropping the turbo down but there isn't any evidence of leaking from the manifold face... I doubt that the manifold is leaking due to the way the noise only comes on between about 2500 and 4000rpm. if it was the manifold it be constant, though that doesn't explain why a crack in the housing isn't constant too.

I'll take the turbo I got from you to see my guru today. I think the best course of action will be to rebuild that core and buy a new housing for it, then I can swap turbos in a weekend.

Would it be smart to have the new housing ceramic coated? Does that help prevent cracking?

[sambb]

sorry just noticed your other pic of the exhaust housing entry. Those cracks are nothing compared to most I've seen and its thick casting behind there so I doubt you'd have any chance of a leak there. The option is you can get that engineers dye that bleeds down into cracks and can give you an idea of how far they really go or if they are going through to the outside. Yeah I think getting it internally ceramic coated would help but I've seen so many ceramic coatings degrade and 'peel' that I'd be worried what flecks of it might do going through the turbine. You said your wastegate port was crack free yeah? If the flapper cant seal you'd definitely see your issues. Also the flappers pivot/hole. Thats not eaten out so badly that you'd get a leak through the bush is it?

[simon k]

You said your wastegate port was crack free yeah? If the flapper cant seal you'd definitely see your issues. Also the flappers pivot/hole. Thats not eaten out so badly that you'd get a leak through the bush is it?

Dunno about cracks but when I reset the flapper preload a little while ago I gave it a good wiggle and there didn't seem to be any wear going in the wrong direction, and there isn't any soot or marks from exhaust leaking around it, so I think it's fine but no way of knowing without taking it off.... which takes me back to saying I'd prefer to have a known good turbo ready to go and swap it out rather than just remove it to inspect and cross my fingers that it doesn't fall to bits

[sambb]

Audi Turbos, XS Power Inc. these guys turbos have been in plenty of VW's here. Of the forum members I'm aware of who have fitted them I havent heard any horror stories. you have to look around in the VW and audi pages on their site but they do reproduction K03s-058?, K04-001 , and K04-001 with hotupness which is the XL I think but you'd need injectors/maf/retune for that one.

[simon k]

It was just the manifold gasket.... shrugs...