Hi Everyone,

I believe my 2003 XKR has a vacuum leak at the supercharger ducts. This is definitely not the first time this has happened and I believe that it has triggered the P0171 and P0174 codes. I can hear a hissing coming from around the back of the supercharger. At first I thought it was the breather tube going into the elbow of the snorkel/air intake pipe but I could actually feel it I think around the duct gaskets that are shaped like donuts. Sprayed some brake cleaner in that region and sure enough the RPMs changed almost immediately and she idled rough for a few seconds.

My question is, is there anything tricky that I should be aware of when changing these parts out? I figured you would just disassemble the supercharger starting with the top plate with the V8 on it and work my way in from there. Also, I just had the supercharger disassembled by my mechanic for valley hoses and all of the gaskets are new. Should I replace the top plate gasket at the same time or do you think I can reuse that one?

Thank you for your help!

 

Hi, you should look at the seals that connect the charger lid (V8) to the intercoolers. There are 2 versions of seals. Pre and Post TSB xxxxx.
If you fit post tsb seals in pre tsb retaining plate setup, they will suck in at idle easily. After that happens they also leak under boost.
If you have pre tsb setup incl older type seals this can also happen, hence the introduction of the tsb to mitigate that possibilty.
I reinstalled older type seals with polymer (degreased) no more sucking in after that.

good luck

 

Revised part TSB.

 

Thank you for the info guys. I did some due diligence and have the updated seals coming. I am hopeful that the plates in my car are updated but fear that might not be the case hence the recurring issue.

As for changing these out, is it as simple as taking off the bolts and putting in the new seals? I want to say that I read somewhere that there are bolts in the supercharger that have nuts that will drop into the supercharger if they are fully removed. I cannot see how this would be the case with these particular seals but do not want to make a tragic mistake! Also, would you reuse the square gasket under the cover that says V8 or would you fit a new one?

Thanks!

 

Hi Motorcarman,

I reviewed the TSB and found the part numbers for the updated clamp plates. What is odd is when I search for them online I find that they are for a 2000-02 XKR and then 07 and later according to a few sites. Isn't the supercharger identical for the 2000-02 and 2003-06? If so, I would think those are the right part numbers for my 03 but I am just a little concerned about what I am seeing listed on these part sites.

Thanks,

Corey

 

I expect yours is mostly similar to my XKR 2000. I had the new type of seals installed by PO, but plates were old type. Removing and installing is not that difficult. Take out inlet tube from TB and you can reach the bolts with an standard 3" or 4" extension. You can drop the bolts where you can't get to them so be carefull and put some cloth underneath or use magnetic 10mm socket to undo the the bolts. Nu nuts fall inside when taking bolts out. Be carefull when engaging them back in the threads because bypass hoses prevent you from accessing the bolthead straight. I learned the hard way...
I reused the square gasket. (even when I had a new one available, as they seemed equally suitable still)
Best to take a look at the thin vacuum hoses to the bypass valve (front of TB) and fuel press regulator (passenger side cyl-bank aft) for leaks as well. (does't hurt and may be causing related issues)

 

Managed to replace the inlet duct seals and it fixed my P0171 and P0174 codes. The seal on the passenger side was torn at the bottom which was likely where the leak was occurring. I had difficulties with some of the bolts because my 10mm socket would not fit in the tight space. I ended up getting a 1/4" drive 10mm deep well socket and it worked perfectly. It is very narrow so it fit in the tight spaces nicely and managed to solidly remove a couple of bolts where the supercharger outlet duct cover was getting in the way of my 3/8" 10mm socket.

One issue that I came across, which I likely caused myself, is that there was a small hose coming out of the outlet duct cover (the piece with the V8 on the top of it). This tube comes off of the passenger side and looks like it goes into a sensor or device near the front of the fuel rail. The car is running great but there is definitely a vacuum that this hose creates and I need to figure out what it is and replace it. Aside from that, everything went pretty well and I did some guesswork on the torquing. The outlet duct cover bolts (the four with a seal attached) were noticeably looser than the inlet duct/clamp plate bolts. I tightened those just a tad beyond the point where the socket wrench met resistance. Probably about the same degree of tightness that I use for a valve cover gasket. Tightened the inlet duct/clamp plate bolts much tighter.

After the fact, I was able to find an X308 service book online. In this book it looked like they referenced 9-11nm for the outlet duct cover and 18-24nm for the inlet duct/clamp plates. Hope this helps anyone who tries to tackle this job in the future and I want to thank everyone for their help!

 

Well done!

I use 1/4 with extension as there as well..
About the little hose, it is for regulating fuel pressure.
Under boost it will make the regulator change to higher fuel pressure.
No leaks allowed for proper operation.

take care and enjoy,

 

Thanks! It feels good to have her up and running again. I was actually able to fix the hose by running out to Advanced Auto Parts for the Dorman Auto Grade Hard Vacuum Tubing Connector Assortment. Part number 47307 over there. The second smallest connector perfectly replaced the broken plastic connector. $5 fix. Always nice when it is something cheap and easy.