PO172 97 850 NA

Post by **januwan** » 02 Aug 2026, 11:04

Just got the PO172 code. I was checking my vacuum lines and found a small crack in the elbow that connects to the passenger-side manifold. Is it possible to replace this elbow without removing the manifold?
I also want to clean the MAF sensor, but I don't have the wrench for the star bolt with the pin in the center. Does anyone know the proper name for this bolt and where I can buy the wrench?
Any other suggestions for removing the code would be greatly appreciated.

Post by **misha** » 02 Aug 2026, 13:57

It is possible but a lot of hassle,remove the plastic hose/housing which goes onto throttle plate and whole pcv end which goes on it.

Go from throttle plate side with little hard vacuum pipe behind intake manifold and first connect the rubber elbow onto nipple on intake manifold...then connect it to the pcv end.

About maf....remove the ribbed hose and whole Maf from air filter housing...spray Maf cleaner without touching the sensor...let it dry and re-install.

Post by **matthew1** » 02 Aug 2026, 17:00

This one? 2nd pic viewtopic.php?p=233700#p233700

IIRC I took off the coolant hose. It's tight but do-able. I think I used long-nosed pliers. Ignore the lack of elbow, it's all the same whether it's elbow or flexible line as far as getting in there.

Post by **abscate** » 02 Aug 2026, 17:52

januwan wrote: 02 Aug 2026, 11:04 Just got the PO172 code. I was checking my vacuum lines and found a small crack in the elbow that connects to the passenger-side manifold. Is it possible to replace this elbow without removing the manifold?
I also want to clean the MAF sensor, but I don't have the wrench for the star bolt with the pin in the center. Does anyone know the proper name for this bolt and where I can buy the wrench?
Any other suggestions for removing the code would be greatly appreciated.

It’s a security Torx bit. You can buy them ftom Tekton tools in GRR , michigan

5 point Security torx, not a standard Security Torx...Storx? children coming?

Post by **scot850** » 02 Aug 2026, 19:59

I got the 5 point Torx security bits from Amazon. I bought 2 different packs, one T25 5 point and a 2nd with multiple sizes. Now they always go to the junkyard with me to pull MAF sensors if they are still there.

Neil.

Post by **matthew1** » 02 Aug 2026, 20:17

Security torx bits at Amazon, my affiliate link embedded.

Post by **dalel** » 03 Aug 2026, 15:10

Did januwan get the info he needed? I do like matthew's solution.

I just did a PCV kit on my v70. I think its pretty much the same engine. I attached a picture to be sure. I looked at it again and it would be pretty tough getting the elbow into the wider hose that goes under the manifold. Probably if you had to... with a couple of long needle nose pliers. If I were januwan, I'd buy a manifold gasket and pull the sucker to fix the hose... Dale L

Post by **abscate** » 04 Aug 2026, 03:58

scot850 wrote: 02 Aug 2026, 19:59 I got the 5 point Torx security bits from Amazon. I bought 2 different packs, one T25 5 point and a 2nd with multiple sizes. Now they always go to the junkyard with me to pull MAF sensors if they are still there.

Neil.

Fine for the MAF bolts into plastic, but a security torx bit is a lot weaker than a standard torx bit fue to the “hole”

I’m getting old, cranky, and allergic to cheap tools

Post by **erikv11** » 04 Aug 2026, 07:33

Pay close attention to Neil's post: the MAF has a five point security Torx head, unlike generic Torx which is 6-point.

If you just buy a standard security Torx set you won't get a bit that fits.

You can also take it out by just clamping on a pointy vise grip, and/or tap it with a punch to get rotation started. But to clean the MAF leave the Torx alone, like misha says.

Post by **januwan** » 09 Aug 2026, 23:37

Thank you for the feedback. I patched the crack in the elbow, but it did not fix the problem. I also found other issues. There is a lot of oil behind/below the manifold, and I failed the glove test. Next weekend I will be doing it for the third time. Second, because the kit I bought contained URO junk.
This time I may go with Matt's modification
And I made a stupid mistake ordering a security wrench with a 6-point star instead of a 5-point (pentagram).

Thanks again.