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05 CTS 3.6L timing chain job, tons-o-pics (I mean tons)

191K views 144 replies 47 participants last post by  RyanY 
#1 · (Edited)
Subject: 05 CTS with the 3.6L with Approximately 70-75,000 Miles.
Complaint: Timing Chain Rattle, 2+ quarts oil consumption between 3,000 mile intervals using 10w30 syn (viscosity increased due to chain noise), Phantom Coolant Leak







The preliminary parts needs were met by RockAuto.com, additional parts were sourced from the dealer as well as Autozone. The timing chain set was from Autozone specifically and was reasonably priced compared to what one might expect to piece it all together at the dealer.




The cosmetic engine cover is removed here:



The air inlet assembly below is to be removed. The small hose shown on is the fresh air inlet for the PCV system. Basically, fresh, filtered air is led to the driver's side valve cover from this hose.




The fresh air tube continues to the back side of the valve cover.



It enters here, just below the vacuum line leading to the brake booster, and just behind the rear most coil.



One dirty air filter:



One dirty throttle body:




With the air cleaner assembly out of the way you can see the belts and work on removing the radiator fan module.





After the belts came off and the fans came out I moved on to the wiper cowl. I used a battery terminal puller to remove the passenger side arm and simply pressed firmly on the driver's side to release the arms from the wiper pivots.



The passenger side cowl is held in by some 8mm (I think) screws. Once removed you can pull the passenger side portion toward the front of the car as well as towards the driver's front fender in order to remove it.




The driver's side is held in by a 10mm nut screwed in to the left fender essentially.
 
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#31 ·
I'm not sure what to tell you about the images. I've viewed the thread logged in and not, both times I'm able to see them and no one else has mentioned any problems.

A follow up on the patient. Tonight I replaced the lower radiator hose, antifreeze and changed the oil for the final time. If you remember, the lower hose had the broken spring clamp and as it turns out the remains of it were able to cut a small hole in the hose. Also, it was leaking antifreeze from that hole and was a few drops short of a steady stream. The coolant reservoir was still over-filled (I was anticipating an air pocket to purge out) and the owner had only driven the car about 200 miles since the repairs.

Previously, we were putting in 10w30 full synthetic due to the timing chain noise. The oil change tonight we dropped the viscosity back to 5w30. I've been to a few classes in the last couple of months and they are really pushing hard for folks to pay attention not only to oil viscosity but also the "GL" numbering on the back of oil container. The instructors are also saying to make sure that you are using oil that is x,y,z certified and not the kind that "meets or exceeds" x,y,z standards. Only the oil that is certified is considered acceptable by the manufacturer of the car because "meets or exceeds" means the oil company used their own testing methods and CLAIM it is the same. The oil that is certified has basically been sent OUT to be examined and certified. May be a bit too much detail and yeah, I feel it's a bit of a sham but if you're buying a new car it's better to be safe than have your warranty voided.

The new hose was about $25.00 from NAPA but I don't have the paper work with me to give a part number. I may get around to posting more info later.
Doug
 
#32 ·
Wow Doug, what an amazing job! How much for labor if we bring the parts and helping hands? And where do we start scheduling weekends and send a down payment for a reservation!?!? :) Just create a shared Google Calendar and put the cost you would charge for each weekend from May to October. You would clean up!

Thank you! Great job!
 
#33 ·
My labor rate at home is $50 an hour and it's about a 14 hour job per Alldata so that's about $700.00 labor but I could probably work a deal if someone's serious about it.

As far as the helping goes... I can't seem to paint a big enough square around my work area to keep people out of the way. My current favorite saying is "Automotive repair is not a spectator sport." and most of the time there's no room for a second body under the hood. That being said... I don't mind company, it just kind of slows down the process sometimes.

On an update note, the car went to Myrtle Beach, SC and back to the Raleigh, NC area last weekend after replacing the lower radiator hose and changing the oil for the final time. With a little bit of spirited driving here and there and mostly highway speeds (where the oil consumption showed up the most prior to repair) the oil was just a hair below the FULL dot which is exactly where it left at.

While under the car I checked for oil and coolant leaks and found none so while I'm a bit hesitant to say it but it looks like this one is fixed both on the coolant loss (lower hose), oil consumption (cause unknown) and the timing chain rattle (excessive mileage on oil change interval).

On the trip meter, the 400 mile trek lowered the oil life to 96%. Is my math right here in that 100 miles = 1% and 10,000 = 100%? Supposedly the monitor takes other things in to account than just mileage but seems to me that there's the timing chain failure cause right there.
 
#38 ·
I would rate it about average when it's repaired. I mean it's not a sewing machine Honda but it's not a noisy lifter 4g63 (mitsubishi 4cyl) either. I'm still wishing I had that last tensioner for the primary timing chain in there because the mechanic in me can block out the radio, exhaust note and cars around me and still pick up on a very very faint chain noise. But I'm tuned in to it too so 99% of the rest of the world would never even hear it.
 
#39 ·
Truly an excellent thread, Doug. You have an amazing skill in that you can do the work, understand how it works and document your work. Having oil consumption issues with our '07 3.6 with 73k, which is rapidly getting worse as it approaches 1 quart per 1200 miles, I wonder if you could comment on why you think it was the failing chains that cause oil consumption?? I have been expecting problems at the Rings. I don't think I have the chain clatter

Now that there is a few months on the engine, can you report on the oil consumption since your work on the engine?
 
#40 ·
Well, to be honest I can't really explain it. There were no fault codes nor performance issues. I did no fuel trim monitoring prior to nor after repairs and aside from the noise and the oil consumption I had no reason to dive in to the job for my friend.

Additionally, I changed out the PCV orfice at the same time as the timing chain repair so I can't differentiate between which part of the repair work really caused the reduction in oil consumption.

I have put in PCV valves/orfices on cars where oil consumption was an issue and that ALONE took care of the problem. In those situations, if the valve was gummed up then it could be stuck open causing full intake vacuum to be applied to the crank case all the time. If it's stuck closed then there wouldn't be sufficient breathing in the engine and oil caking or external leaking may occur.

It's my opinion that the noise was caused by a lack of lubrication as described in previous posts in this thread and others regarding oil change intervals. This lack of lubrication caused excessive wear on the primary timing chain guides (mostly, some on secondary) and thus gave the noise. However, I can't seem to justify in theory how intake or exhaust timing can contribute to oil consumption and still not throw a check engine light on a newer car like the CTS.

I'll try to get up with the owner over the next couple of days and follow up with mileage and oil level but like most other folks that have done the repairs... it seems to be fixed.

Cheers,
Doug
 
#41 ·
The oil comsumption is still there, each time he brings it back in to me for an oil change the oil is at least a quart low, most of the time lower than that. The condition seems to be worse when the car is driven on the highway for several hours. I can't be more specific than that because I don't believe the owner is properly checking his oil nor keeping track of it to say "For every 500 miles of open road driving I consume "x" amount of oil compared to 500 miles of in-town driving it consumes "y" amount.

He did have it towed back to my place with a coil that melted down. The left bank coils and injectors all share one fuse while the right bank coils and injectors share a different fuse. So when the injector melted down it shorted to ground and pop the fuse. Oddly enough it would still run on just the right bank but obviously, very poorly. Also, in this visit there again was nothing on the dipstick. I double checked all my grounds, checked for wiring melted/rubbed/damaged and found nothing. It's been a couple of weeks since I repaired it but have not had a re-occurence of this failure. The coil was melted basically in the housing between the spark plug and the electrical connector. The connector and the spark plug were both re-useable with no signs of damage nor indication that they were the cause. I'll see if I can find pictures and update this weekend or something.
 
#43 ·
Finished changing chain on mine,had 71000 miles on the engine. Pretty straight forward job, toughest part was setting chains (cam locking tools help big time), had about 12 hours into the total job. Be sure to change fuel injection o rings while you are in there. I actually didn't have much wear on the gears or chains, but had leaking timing cover to fix anyway. Car runs great, increased gas mileage and does not consume oil. I will upload pictures in a few days
On a side note if you had a mysterious coolant leak, check the water pump gasket. Make sure you use AC Delco gasket, instead of aftermarket.
 
#45 ·
Doug in NC AWESOME POST, Thank you for taking the time and effort to put that together, you probably added at least 2-3 hours to the length of the job with all the pics. I would like to add a couple of notes though.

1. You do not need cam holders if the proper timing procedure is followed. As per Dougs post line up the links with the gear marks - To make sure the cams are in the right position the flat spots on the rear of the cams should line up, i.e. you should be able to put a straight edge across them.

2. Be VERY careful with the timing link that lines up with the hole in the left bank idler gear, THIS IS A CRITICAL STEP THAT WILL MESS UP THE REST OF THE TIMING JOB IF THE LINK IS NOT LOCATED PROPERLY. It is very difficult to see the link through the hole, I used a small pick through the hole and was able to time it right that way.

3. Install the Primary chain per Doug's instructions. Make sure the right bank cam flat spots line up like in note 1. However when finished installing the primary chain turn the crankshaft approximately 30 degrees clockwise. The Right bank chain should slip on with little difficulty.


This is how it is described in the book and by the mechanic that I spoke with when I completed my replacement after my chain broke. BTW he was completing 3 timing chains per day!!

I hope this helps
 
#47 ·
They fail so while you're there, replace them. You don't have to squeeze every possible mile out of auto parts. The extra labor is negligible at that point, but changing 10000 miles later and its gonna hurt your purse. If only I'd have changed it when I did the chain...you don't want that to happen.
 
#49 ·
Yeh, timing chains affect starting.

For the engine to start, it has to have compression, proper fuel/air mixture, and spark at the exact perfect TIME. The timing chains establish when the valves are perfectly closed so that the compression is at or near its peak. So if the spark is occuring before or after the compression peak, it is not going to start the first time around. The ECM can make up for alot of slop though.

A dirty air filter or dirty throttle body and butterfly can cause slow starting too. A weak battery shouldn't affect the actual ignition part of starting, up to a point. If everything else is perfect, as long as there is charge enough in the battery to supply a spark, the engine should fire the first time it tries.
 
#52 · (Edited)
Just tackled the tear-down of my '04 CTS 3.6L yesterday, only 90,000 miles. Labor wasn't as bad as I thought. This post certainly helped out a bunch. Most annoying part of dis-assembly for me was the alternator (~20 minutes to wiggle the thing enough to get the 10mm nut on the back). But then again, I haven't re-timed the engine yet (still waiting on the timing set to come in).

I really didn't have any noticeable rattling or oil consumption. What I did have was a whine when the rpms went above like 1500. With the hood open, standing at the front of the car, and revving to about 1500rpms or higher, it just sounded like a scraping, roaring, whine. Idling at 600-700 rpms though, the noise was unnoticeable.

From the inside of the car, driving with the hood closed, it turns into more of a whine than anything else. But with the hood open and standing out front or passing through a tunnel, it sounded like a bad pulley bearing or something to that effect. When I removed the tensioner/guide for the primary chain, the attached picture is what i found.

Seems to have the same pitting that Doug in NC had. Wonder why this happens/if this is causing that noise. Guess I'll know in a few days
 

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#57 · (Edited)
Most annoying part of dis-assembly for me was the alternator (~20 minutes to wiggle the thing enough to get the 10mm nut on the back).
I know it's too late for you, but for others, it is not necessary to remove the alternator first. Just remove the bracket and displace the assembly. At least, on my SRX, this worked, and I doubt there are any differences that would require a different procedure. Also, you don't have to remove the PCM from the bracket, or disconnect it. Finally, no disrespect to Doug, I found it easier to remove the intake manifold as one piece, disconnecting the fuel line at the rear, and not disturbing the injectors.
 
#56 ·
I've gotten to the point I'm going to remove the heads to have them rebuilt (a la briggy). My chain broke. here are some photos of the chain and chain guides I removed.
Wow. I would seriously recommend the shop remove and replace the oil check valves in the head. I am very curious about this engine - mileage, how long you had it, how long it was making the terrible racket it must have been making, OCIs, oil selection. Any way you could get us some pix of the broken link, the outside of the chain, and the sprocket teeth? I would seriously consider a rebuild, with new camshaft actuators. And don't forget a new oil bypass check valve for the oil filter cap.
 
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