So, cij911 and I tried to adjust the preload on his wastegate actuator yesterday.

He suffers from a problem whereby his boost builds very quickly to about 16-17psi, and then lazily makes it way up to the target boost of 20-21 psi. This seems to be a classic symptom of a wastegate actuator with not enough preload, so we thought we would give it a shot.

Keep in mind, neither of us have wrenched that much on the car, so don't make fun of us too much.

So we get the top manifold heat shield off with no problem. Then we remove all of the bolts for the lower heatshield, but can't remove it. It seems the O2 sensor is in the way?

Questions:

- can you remove the lower heatshield without removing the O2 sensor?
- if not, what is the correct procedure for removing it? (I saw a how-to from superhatch for the 10.5 hotside and it just says 'remove the O2 sensor and lower heatshield' without further details)

Even without the lower heatshield fully removed, we were able to push it out of the way a bit and get the arm off of the pin. But then there simply was not enough room to make any adjustments to the turnbuckle. So we had to just put it all back together without making any adjustments ...

What's the best way to get at that sucker???

 

Sadly enough the best way to take it out is with the radiator out :| I'm sure it can be done otherwise but you'll be risking poking a hole in the radiator (which I've done).

Once you do get it out.. you can cut a slot into the o2 hole in the heatshield which will allow it to come out with the o2 sensor in... I chose to leave the lower heatshield off as it's been nothing but a headache

Maybe some other guys can chime in with a better idea.

 

+1

 

I've changed out several from the top side. I think all we removed was the stock airbox. It wasn't easy and it yeilded a lot of cuts and scrapes on the hand!

I believe it's easier to attack from the bottom side. Especially if you have a lift (or at least ramps/jack and the plastic tray has been removed.

 

If your car is over 30K, removing the radiator is also a good chance for you to flush and refill.
And yes, you WILL mess up the radiator if you won't stick something liek a cardboard in there :}

 

I managed to tighten my actuator with O2 in and radiator in. If I did it again I would take them out for comfort.

First of all before you dig into that, just do a leak check to confirm that's not the problem.

Another point: If actuator has weak preload (very small chance it is from factory) I think it would behave different than what you describe. It sounds to me like a boost leak.

 

I've never been able to get the lower heat shield off without removing the radiator, even with a slot cut for the O2 sensor. Anyone who has been able to do that must have a lot of bent up fins on their radiator!

 

Thanks for the replies folks. I was hoping that removing the radiator wasn't really necessary for this job, but it obviously would make it a lot easier ...

And I hadn't thought about a little cutout for the lower heatshield to clear the O2 sensor ... good idea, thanks.