How to - Camshaft actuator(phaser)/sprocket replacement

[Astra08]

Good Morning All,

I was experiencing some issues with engine performance on my '08 Astra. After some troubleshooting efforts, I was able to track down the the cause of the problem to a defective camshaft actuator(phaser)/sprocket assembly; this is not to be confused with the camshaft position actuator(CMP), which can also be a common source of problems by itself.

I put together an 18 page write-up on how to diagnose and repair. Because of it's size, I am attaching a link to an Adobe .PDF instead of posting the entire document:

https://drive.google.com/file/d/0B7N...ew?usp=sharing

I will post the initial symptoms below in case any else if having the same issue and wants to read the document further. If anyone has trouble accessing the document, please let me know and I can email you a copy.

AstraLaVista - I hope you don't mind, but rather than write a lot of additional steps, I included your very nice Timing Belt replacement write up for reference where required.

Please feel free to provide any feedback or corrections as needed. Hopefully this will save some people time and money, as having a dealer perform this service can be quite costly.

--Mike

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On my vehicle, a 2008 Saturn Astra with the 1.8L Ecotec and approx. 118 K miles, I encountered this problem as described in the first paragraph. It started several months prior, with valvetrain noise at engine startup for 3-5 seconds, an intermittent P0016 DTC along with the check engine light, and finally persistent valvetrain noise. At this point, I chose not to drive the vehicle any further to avoid potential engine damage, due to the interference design of the Z18XER 1.8L Ecotec engine.

This continual engine noise, which could be heard being more pronounced from the back (intake) side of the engine, was occurring at all RPM’s, and not just at startup, although it was much more noticeable at the lower end of the RPM range (idle to 1500). It seemed like the typical ‘slipped’ timing belt scenario, but having replaced the timing belt less than 15K miles ago, and performed a visual inspection on the alignment marks and belt, this seemed unlikely. I went down the path of troubleshooting the electrical components first, to rule out some of the more common elements which might be causing this issue.

After using the process of elimination and ruling out the typically seen causes, i.e. defective camshaft position actuator and/or clogged screens, camshaft sensor, crankshaft sensor, low oil pressure and even excessive lifter clearance causing the noise and poor performance, the issue was then isolated to either the phaser/sprocket assembly or the sonic reluctor ring which is located on the crankshaft. Had it been the latter, it would have affected operations for both camshafts, not just the intake, so that indicated isolation of the issue back to a worn intake camshaft phaser, consistent with the ‘Bank A’ DTC’s which were being triggered.

Unlike traditional camshaft gears which are fixed in position and of a one piece design, the ones used on the 1.8L Ecotec engine are of a two piece design. These combination phaser/sprocket units have internal ‘vanes’ which vary in position, based on PCM commands modifying oil flow to the phaser/sprocket assembly via the camshaft actuator. After time, this phaser unit can fail to operate properly and cause the symptoms listed above.

Issue mitigation consists of removing and replacing the defective camshaft phaser/sprocket assembly; removal/re installation of the timing belt is also required as part of this effort. The job will probably take about 3-4 hours for the average DIY’er to complete, and fortunately most of the work can be done from the top side of the engine compartment.

[Astra08]

Updated link for document, thanks:

https://drive.google.com/file/d/0B7N...ew?usp=sharing

[smwalker]

Very nice write up!

Could you post a picture of the outer bolt cover separate from the engine? What does it screw into? Are there threads in the cam shaft bolt recess?

Only part that is confusing.

[velocast]

Thank you for your efforts and informative article. It helps to make life easy. I got one copy all ready. Thanks!

The rattle noise is a well know problem on the Ecotec Z18XER. Because an engine has too many moving parts, it is hard know exactly where the noise is coming from. Here is the breakdown:

1) Cam position sensor (electrical)
2) Cam actuator solenoid (electromagnetic valve)
3) Cam actuator phaser (hydraulic)

The cam position sensor sends information to the computer. The cam actuator solenoid receives signal from the computer, and then feeds oil to the cam actuator phaser. Inside the cam actuator phaser there is a rotor. If you add oil to one side of the rotor's lobe, and remove it from the other side the rotor moves advancing, or retarding the camshaft.

TROUBLESHOOTING: If the rattle noise is coming accompanied by code P0011, P0016, or some other related codes, it must be the camshaft actuator phaser.

NOTE: I forget to mention another important part that is not related to the problem but may need to be replaced.
4) Crankshaft position sensor (electrical)
The crankshaft position sensor, and the camshaft position sensor control the ignition timing. They send signals to the computer to let know when to inject fuel, and spark firing.

[Astra08]

Originally Posted by smwalker

Very nice write up!

Could you post a picture of the outer bolt cover separate from the engine? What does it screw into? Are there threads in the cam shaft bolt recess?

Only part that is confusing.

SM,

Thank you very much! See if this helps, I assume you mean the upper timing belt/camshaft cover? It uses two (2) E-10 female Torx bolts for fastening.

If not, what section specifically and I will look to clarify. Thanks.

[Astra08]

Originally Posted by velocast

Thank you for your efforts and informative article. It helps to make life easy. I got one copy all ready. Thanks!

The rattle noise is a well know problem on the Ecotec Z18XER. Because an engine has too many moving parts, it is hard know exactly where the noise is coming from. Here is the breakdown:

1) Cam position sensor (electrical)
2) Cam actuator solenoid (electromagnetic valve)
3) Cam actuator phaser (hydraulic)

The cam position sensor sends information to the computer. The cam actuator solenoid receives signal from the computer, and then feeds oil to the cam actuator phaser. Inside the cam actuator phaser there is a rotor. If you add oil to one side of the rotor's lobe, and remove it from the other side the rotor moves advancing, or retarding the camshaft.

TROUBLESHOOTING: If the rattle noise is coming accompanied by code P0011, P0016, or some other related codes, it must be the camshaft actuator phaser.

NOTE: I forget to mention another important part that is not related to the problem but may need to be replaced.
4) Crankshaft position sensor (electrical)
The crankshaft position sensor, and the camshaft position sensor control the ignition timing. They send signals to the computer to let know when to inject fuel, and spark firing.

Thanks for additional feedback Velocast. It would good to add these for a bit more clarification.

I vary with you on the P0016 always being camshaft actuator phaser related however, at least directly. A defective camshaft actuator solenoid and/or it's clogging of the two orange screens can cause the same DTC, however it's indirectly impacting the phaser via this issue. I think it's important to rule this out prior to going straight to replacing the phaser assembly itself, which hopefully people will do. Thanks.

[smwalker]

Originally Posted by Astra08

SM,

Thank you very much! See if this helps, I assume you mean the upper timing belt/camshaft cover? It uses two (2) E-10 female Torx bolts for fastening.

If not, what section specifically and I will look to clarify. Thanks.

I tried to cut and paste but the pdf wont let me. It was what you were trying to explain right before figure 15. then in figure 15 I connot tell what part is the cover and what part is the sprocket.

[Astra08]

Originally Posted by smwalker

I tried to cut and paste but the pdf wont let me. It was what you were trying to explain right before figure 15. then in figure 15 I connot tell what part is the cover and what part is the sprocket.

Ah, I see what you mean, it is a two piece design.

There are two photos below. The first shows the 'outer' bolt cover, which is simply threads into the sprocket. When you remove it, you will see the actual bolt holding the sprocket on,, and the threads around the center of the sprocket cover itself.. HTH.

[velocast]

I agree with you! It depends how early did start the problem, and how quick got fixed. In fact, a defective cam actuator solenoid may start damaging a brand new cam actuator phaser.
My problem was the rattle noise, and code P0011. The rattle noise did start from quiet to loud, way early on until code P0011 start showing. So, I did replaced all those 3 items along with the timing belt @ 50K miles to be worry free. Since then, no more rattle noise.

[smwalker]

Originally Posted by Astra08

Ah, I see what you mean, it is a two piece design.

I see thanks getting a clearer picture of it now in my mind.

[@dmin]

I recently just bought an Astra and looking to do the timing belt in a couple weeks and checking valve clearance while it's apart.

I've notice that it will occasionally make a diesel like sound for about 2 seconds sometimes, not always. There are no engine codes though and it runs fine to me. I thought it was just oil not getting somewhere at start up. This has my interest.

I plan on pulling the solenoids and cleaning the filter with a cleaner, I'm not to hot on the idea of pulling the filters as this is a high mileage car now (96k).

Where is the "play" found? I'd like to inspect these cam sprockets while everything is apart. Or would you suggest just replacing them while I'm there?

[Astra08]

Originally Posted by @dmin

I recently just bought an Astra and looking to do the timing belt in a couple weeks and checking valve clearance while it's apart.

I've notice that it will occasionally make a diesel like sound for about 2 seconds sometimes, not always. There are no engine codes though and it runs fine to me. I thought it was just oil not getting somewhere at start up. This has my interest.

I plan on pulling the solenoids and cleaning the filter with a cleaner, I'm not to hot on the idea of pulling the filters as this is a high mileage car now (96k).

Where is the "play" found? I'd like to inspect these cam sprockets while everything is apart. Or would you suggest just replacing them while I'm there?

The "play" is on the end of the camshaft where the sprocket attaches. Some brief startup noise is not unusual, and you might want to check the valve clearances with a feeler gauge as well. I wouldn't remove the camshaft actuators unless you absolutely have to.

There's a write up at the thread below on checking valve clearances, along with a file to help record gap values:

http://www.saturnfans.com/forums/sho...d.php?t=180444

[spitoon]

Hi All,

I understand I'm late to the party here, I hope someone is still around

Great write up, I really appreciate the detail.

My daughter has a 2008 Astra with the symptoms mentioned here. I have replaced the 2 actuator solenoids and both camshaft position sensors, as well as the crankshaft position sensor. The problems still exist.

I'm looking to tackle the timing belt and actuator sprocket replacement very soon, but I have a question.

I was planning to replace both the intake sprocket and the exhaust sprocket, but I cannot find the exhaust sprocket at any parts shop (online or in person), all only refer to the intake sprocket.

The error code is P0017, which refers to Bank 1 (which is the intake bank as far as I can deduce) so am I safe to assume that I can get away with only changing that one? I figured that once I am in there, I may as well change both, but as mentioned, I am having a hard time finding one specific to the exhaust side (partsgeek, rockauto, local Auto Value etc.).

Any advice would be appreciated and thanks again!


EDIT: When I put the part in the cart at RockAuto, it mentioned that there are 2 per vehicle and these parts are often replaced in pairs. Although it is specifically labeled "intake", I may have answered my own question...

[AstraFasta]

Per the PDF the parts are:

Intake camshaft phaser assembly GM PN# 55567049*
- Intake camshaft phaser sprocket bolt GM PN# 12992403
- Crankshaft bolt GM PN# 24447224
* If replacing the exhaust camshaft phaser assembly, the GM PN# is 55567048.

I find these parts all over the internet (take a look at ebay and amazon also). Virtually similar 1.8L was used on the Chevy Sonic and Cruze for example so that can help you find parts.

If you are replacing the timing belt, get a kit with the idler pulley, tensioner etc. The kit is cheap and these rotating parts wear out on the Astra.

Finally, doing the timing belt is probably close to 8 hours for intermediate level DIY type at home with all tools. Once you have the timing belt removed, those sprockets are super easy to access, so I think the sprocket work will be relatively quick and easy.

[spitoon]

Thank you! I did order the timing belt with the idler and tensioner etc.

I was able to find the exhaust phaser sprocket on ebay.

I will say I am a bit curious as to why most sites (and my local parts store) only show the intake side available. It seems to me that if you have it that far apart, it would make sense to replace both.

The Rock Auto site actually has a note that pops up when you put "1" of the intake phaser sprockets in your cart. It says they are usually replaced in pairs. The note goes away when you add "2" to the cart. I actually remember the same thing happening when I purchased the solenoid actuators several months ago.

Anyways, thanks again.

[Astra08]

Glad this was helpful to you. Fairly straightforward job, really.

[AstraFasta]

Symptoms
- We had a loud knocking for about a second on first morning start up for several months.

- Random unidentified engine rattles and clunks at idle on passenger side of engine (I thought maybe water pump or alternator at first but pullies are tight, smooth, and don't wobble, no leaking, etc.).

- Otherwise engine ran superbly.

Work
Knocking seemed likely worn camshaft actuator sprocket. But after reading the PDF and recommendations here, I decided to test and clean both Cam actuator solenoids as that is much easier than replacing the sprockets.

- Several years ago we removed the orange filters.

- Visual inspection, both actuators looked to be in excellent condition.

- The black filters at the end of each actuator were rather clogged, especially the exhaust side.

- I have seen some people claim about 5 ohm spec on the internet. But both my actuators measured very closely to 11 ohms so that seems fine.

- I ran 12v via test power supply and both solenoids operated fine, with identical positioning resting and powered.

- Cleaned solenoids & black filters with brake cleaner and a toothbrush. Also did some cleaning carefully powering solenoids several times.

- Swapped intake and exhaust sides (I had done that before several years ago).

Results
- Knocking sound at start up is virtually inaudible. I'll have to start up for several days to confirm there is any knocking. Hopefully, we have avoided camshaft phaser replacement job.

- Random rattling noises at idle gone. Basically just hear the fuel injection tapping like we did when the car was new (forgot about that). Otherwise virtually silent on idle. Quieter when driving.

- Not sure if drivabilty or mileage improved. Engine already ran superbly.

[AstraFasta]

Originally Posted by AstraFasta

Knocking sound at start up is virtually inaudible. I'll have to start up for several days to confirm there is any knocking. Hopefully, we have avoided camshaft phaser replacement job.

After a week, quck testing and cleaning of cam actuator solenoids seems to have resolved the startup knocking sound.

Might make sense to clean the filters from time to time just to keep engine idle quiet.

[AstraFasta]

Today we removed the Cam actuator solenoids on my buddy's Astra for cleaning only. It is a 125k mile XR with manual transmission. He changes oil about every 5k miles with Mobile One.

Around the 25k mile mark, dealer replaced the intake side solenoid and removed orange screens from only one side (I think the exhaust side). That was due to engine lights (maybe P011 codes)

All black and orange screens looked in new condition with virtually no contamination. We cleaned the screens and metal bodies with brake cleaner for good measure. Car seeems to run just as well as it did yesterday.

[Astra08]

Updated link for the How-to document below:

https://drive.google.com/file/d/1_Xl...ew?usp=sharing