CPAS screen missing!

[svscott]

I have been getting the P0017 code on my 2005 Trailblazer for quite awhile and am finally getting around to pulling the CPAS for cleaning/replacement. I just got the power steering pump removed and the solenoid out for inspection and it only came out with the last 2 screens on the solenoid- the end mesh was clean, the 2nd one was filthy with a hole in one of the ports and the mesh dangling into it but the final two rows had no mesh at all. All of the pics I've seen show 3 screens on the solenoids.

So now I am wondering... is there a chunk of mesh in my engine? I have the old solenoid out and the new one should be at AutoZone within the hour for pickup.

 

[Mounce]

Most likely. Not much you can do I don't think unless you're lucky and it makes it to the bottom of the oil pan and straightens out enough to come out during an oil change.

 

[Mooseman]

Yep, usually people replace the CPAS and all is well. New ones, at least the Delphi/ACDelco, now have a retention wire around them to prevent this. I'd recommend replacing it. Stay away fro Dorman.

 

[mrrsm]

If you follow the Oil Path Flow Diagram for this Engine ...there are only two places the screen(s) can go. Either they can get redirected by the changing directions of the Oil pressure guided by the solenoid and shuttled into or out of the helical gears of the Cam Phaser. Or the other possibility is that if you look at the three openings in the very end of the CPAS... you can see an area where the loosened screen(s) can be ejected through those openings and land somewhere on top of the Engine Head.

If the former event occurs... the screen(s) might get jammed inside of the helical gears inside of the Cam Phaser and be trapped inside. If the latter happens... the ejected screen(s) would eventually just get washed down into the bottom of the crankcase and trapped in the Oil Filter.

In either scenario ...More than likely... No serious harm will be done to the engine because the Oil Galleries are discreet...and the Oil Path is not one of recirculation. The Oil Galleries servicing the Crankshaft are fed below and before the Oil gets anywhere near the Cam Phaser... so whatever happens above those Galleries keeps everything below them... immune.

EDIT:

It would be very interesting to Autopsy that Oil Filter and see in the screens made their way inside... and out of harms way. Oh... and here are two images I took that illustrate the problem with their CAD Head Blueprint that illustrates had they just drilled out a little deeper from the outside in...and cleanly bored the area out from the top down... all of the residual metal blocking the way for the CPAS to go all the way inside would have been removed:

http://s557.photobucket.com/user/60...BLAZERENGINEREPAIR/ACPASPROBLEM?sort=3&page=1

 

[svscott]

Thanks for the replies! I finished up bolting the new part in then took for a quick test drive and the code hasn't come back yet. I don't notice a difference in the way it runs and idles but I'm sure the computer will be happier.
I used my phone video camera to look into the hole and noticed the back wall has a hole in it that doesn't look machined. It seems odd that the hole would be so roughly shaped but she runs fine so I guess (hope) it's OK.
The only other thing I don't feel good about is that the new part didn't feel like it really seated all the way. I twisted and rotated and pushed as hard as I could then just ended up tightening the 10mm bolt - the mounting plate is tight at the bolt but pulled away from the engine a bit at the main body of the solenoid. It's a Duralast brand part from AutoZone.

 

[mrrsm]

The reason the CPAS Unit does not penetrate all the way into the cavity is because the hole it rides into is NOT completely machined all the way through into the head...it stops about an 1/8" or less...and the very end of the CPAS butts up against the residual metal.

I have found this by direct examination in two separate Engine Heads... so it's not a fluke...and it may go a long way towards explaining why so many CPAS units eventually leak Oil and loosen after the solenoid piston shuttles endlessly in and out as the housing attempts to move in the directions opposite the inner plunger valve's movement ... like the recoil of a 105 mm Howitzer.

You can see the artifacts of this wear by looking at the flattened "0" Ring worn by friction and the abrasion marks left behind on the housing near the "0" Ring. If the damned hole were completely drilled through... the CPAS would completely seat and once secured flush with the outer head ... and seldom give us any trouble.

 

[Mounce]

These are real picky on vital parts like the cpas. Dorman and such are usually junk for this application. Always research before you buy.

My ACDelco seated just fine. Got it for ~$40 online.

 

[Mooseman]

And oddly enough for me, the dealer was cheaper than the local parts place

 

[svscott]

I sure am glad I found this forum - Trailvoy used to be solid but members there seem to have mainly gone away so it's nice to have active, knowledgeable users available here. The other forum I've belonged to for my SV650 motorcycle (svrider.com) sets a pretty high bar but I can't complain about anything here!

I'll keep an eye on oil level and will watch for leakage around the CPAS but so far, the O ring looks like it's sealed and I can't imagine any catastrophic failure resulting from this part. I will be putting a few hundred miles on it today and tomorrow so will see If I have to change it out. If needed, next time I'll buy OEM. Hopefully the next time it won't be 30 degrees with a nasty rain/snow mix while I'm wrenching. Winter time car maintenance isn't fun but with three Chevy's at 120,000 plus miles each, it seems I'm always fixing something! My vehicle lineup as of now is an 03 Express 3500 extended glass van, 05 Trailblazer EXT, and 06 Malibu. I also have an 03 SV650S motorcycle and a 1987 Macgregor 26d sailboat so I am ALWAYS modding, fixing, cleaning, etc.

 

[Tiggerr]

Macgregor is a sweet sailboat!
Friend of mine used to have one. Too bad they don't make them anymore... the kids changed the company name and went up-market.. don't think the even make the 26 anymore just the big one (72 I think) ..if I ever get another boat I'll probably try to find an older Macgregor in nice shape.

 

[svscott]

Macgregor is a sweet sailboat!
Friend of mine used to have one. Too bad they don't make them anymore... the kids changed the company name and went up-market.. don't think the even make the 26 anymore just the big one (72 I think) ..if I ever get another boat I'll probably try to find an older Macgregor in nice shape.

Yep, the Mac has been a great little boat for me - easy to sail, inexpensive and tons of fun. In the late 90's, my dad and uncle used to race it out of Long Beach before upgrading to a bigger boat. He gifted my brother and I the boat and was able to get it towed to Missouri on a friend's lowboy trailer and I just had to drive out and tow it back to Erie, PA. My payment for the boat is a mandatory call to Dad each time I use it - I'll take that! We've sailed across Lake Erie, over to Canada a couple times but my trailer was in bad shape so I haven't been able to take the boat many places aside from the trip to and from the marina. This fall, I bought and rebuilt a nice aluminum trailer to fit my boat so I will hopefully be able to take it sailing to some cool locations in the future.

The Tattoo was the Macgregor's kids venture and they seem nice from the few pics I've seen but I don't know if they're still making them. You can pick up a nicely outfitted classic 26d or 26s for well under 6k or the mid-90's and newer versions with 50-100hp outboards are at least double. The idea of motoring at 20 knots on a sailboat to get to a good cruising destination is appealing. Those big 65'-72' Macgregor boats are amazing!