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.
The engine has 155,000 miles on it. We bought the car new. My wife drove it until we gave it to my daughter. She has driven it for the last 2 years. The oil was changed according to the DIC with Mobile 1 until my daughter got the car and she was putting in regular oil. The engine rattle on starting about 1 1/2 years ago. Normally we bumped the throttle and it went away. The car was using about a quart of oil every other fill up. The car began to run bad so I took it to a shop and they said it was a chain guide and repaired it for me. Ha! I wish I'd known about this problem and forum before the engine got bad. Obviously it wasn't repaired. Ktr-sb, your photos have been a tremendous help and have given me the confidence to tackle the rebuild. With briggy and simple 2me write-ups and photos I feel the rebuild is doable. Right now I can't figure out how to get the catalytic converters off so I can pull the heads. I'm not buying any parts until I pull the heads to have them looked at. I can't find a decent low milage LY7 at a good price. I'd rather rebuild what I have than spend money on a high milage engine.
The CATS are a booger to get off. Once you remove the exhaust manifold heat shields (several parts need to be removed before accessing those) you can use a swivel, socket and a long extension or two medium length extensions to remove the CATS. Everything is hidden under the heat shields and they are sort of difficult to remove. Patience is definitely needed when working on these cars. Make sure you have the O2's unplugged before removing the bolts or you'll be spending a couple hundred extra bucks to buy new ones.
That's nasty! What do the heads look like? I'm using conventional oil in mine and I've had the valve covers off since putting the motor in and it's super clean. Did you change the oil when the DIC said it was due or by mileage?
The oil had been changed pretty much by the DIC. We always used a quick-lube place. Usually I checked the oil and topped up about every other tank while my wife drove the car. I'm starting to wonder what oil was being put in the car at the lube place. When my daughter started driving the car (2 years ago), I didn't check the oil as much because all her trips were within a 30 mile radius of the house and we only put gas in for limited trips. Had I been reading this forum, I might have saved myself a rebuild. I'm not a mechanic, but I have enjoyed working on the car even with some of the frustration. I'll post photos when I have the heads pulled off. I usually work on the car after work most evenings for about 1-2 hours after the temp gets below 100. The heat has been crazy here in central Texas the last few weeks. I've got a big fan that makes things bearable. The cars is in the shade in my driveway.
I usually work on the car after work most evenings for about 1-2 hours after the temp gets below 100. The heat has been crazy here in central Texas the last few weeks.
You're probably not that far from me. I live north of San Antonio. I feel your pain. I have a project taking up my garage so everything else is literally done in the shade as well:
I got the drivers side head off. This was the head in a previous photo that the timing chain had broken. The valve are bent and the rocker arm of one of the valves was broken.
Once I get the passenger side head off, I'll check the pistons and piston walls to make sure the bottom end is still in good shape. If the bottom end is in good shape I'll take the cylinder heads in to see about having them rebuilt.
The marks on the chains are strictly for setting the initial timing. On disassembly, only the gear marks should be used to get the gears in the right ballpark for setting the timing on the new chains.
i hear a rattle not really in the morning/cold start ups but if i go to the store and come out it rattles for a couple seconds when i start is there anyway to check to be sure its not something else?
YES! I would strongly recommend you replace the oil filter cap. There is a check valve in there, and I strongly suspect that when it wears out, it causes the noise you are talking about. I had the same noise, even after replacing the chains. If it fixes yours, it could save you a lot of money.
I think the noise is caused by a weak bypass valve spring. The bypass valve lives in the oil filter housing cap:
The cap is part no. 12583470, and is about $30. Replacing it is easiest, that way you don't worry about distorting the new valve when you hammer it in. The new cap will also come with a new blue o-ring instead of the green one:
If you want to save a few bucks, and are good with tools, the bypass valve is part no 25014612, and is about $5.00:
You remove the bypass valve like this. Get a pair of vice grips and wiggle the retainer out - don't worry, the retainer is heavy steel:
Then drive the old valve out with a 9mm 1/4" drive deep well socket (or something similar):
Then gently drive the new one in with an 11 mm 1/4" drive deep well socket (be firm but don't overdo it):
Then you carefully drive the retainer and valve back into the old cap. Make sure you clean the retainer and cap really well, and make sure the retainer is lined up perfectly, or you will end up with an aluminum splinter that will clog the check valve.
Not really. The timing chains and camshaft lifters require oil pressure to keep them from being noisy. I believe the valve in the cap is allowing too little pressure at startup. Assuming you have the same noise as I did, which it sounds like you do.
The cylinder heads went to the shop on Thursday. I cleaned the pistons a la briggy's way. It worked great. Photos are attached. The piston were coated as bad as the heads in my previous post.
The cylinder heads went to the shop on Thursday. I cleaned the pistons a la briggy's way. It worked great. Photos are attached. The piston were coated as bad as the heads in my previous post.
Nice pics. I am trying to study the oil consumption issue, and why drilling out the PCV orifice fitting might make a difference. Could I ask a huge favor? Could you take some well-lighted pics of the passenger's side block, of the drainback holes in the very rear of the block? I am trying to figure out if there is something down there that slings oil up the head. Thanks in advance.
so itll sound like lifters but if it sounds from front its chains ? when it does make the rattle it goes away on its own without tapping the gas. well ill give it a shot and do it anyways its cheaper than chains
My timing cover is back on, new oil put in and everything is in working order. I didn't see any leaks or issues. There are no service engine lights or codes popping up. I'm not mechanically inclined but this was not a difficult job if you have the the right tools/parts and patience. I did most of the work and the mechanic gave me directions, and helped with the hard stuff. (alternator, crankshaft pulley, power steering bracket and setting the timing) I'll give an update when we put the accessories back on.
P.S. this post helped a lot for reference. Thanks Doug NC
This thread is excellent...showing every step. On post #72 though it shows the valves all gunked up from the oil ingestion, yet I was shown a picture showing one w/160,000 miles on that shwed them like new in another thread......Hmm.
Here are what the intake valves on a DI motor with 8 k miles look like:
and the piston tops:
The pictures showing the effects of not running full synthetic are an eye opener as well.
This thread is excellent...showing every step. On post #72 though it shows the valves all gunked up from the oil ingestion, yet I was shown a picture showing one w/160,000 miles on that shwed them like new in another thread......Hmm.
These are not from the same angle, so we don't know what the other side of these valves look like. And we don't know what kind of gasoline was used, or what kind of oil. Doesn't change the fact that my intake valves were clean on the intake side after 160K+ miles of using mostly Shell premium, mostly synthetic, and occasional Berryman's or Techron. Pictures of those valves were posted 7 months ago for anyone who was following my timing chain repair to see. Proving, of course, that you don't need anything other than good maintenance to keep the inside of these engines clean.
I would caution anyone relying on these two photos, or the third, similar one in this poster's photobucket album, to prove anything. If you check the photo's info, it doesn't list a camera, but "CREATOR: gd-jpeg v1.0 (using I..." This is an indication that the images may have been photoshopped or otherwise processed.
Don't know why this guy called me a liar, but it seems that he is threatened by the truth that you don't need a catch can to keep the inside of your engine clean.
I pretty much had decided to do the PCV mod. With the heads still at the machine shop, it's an easy mod to do with the engine apart and also cheap. All I have to do now is make sure I get the pistons and cams in stage I and stage II relationships when I get the heads back on and put the chains in place. I only bent the valves in one cylinder so they will be replaced.
I'd strongly recommend replacing the oil filter housing cap as well - it has a bypass valve in it, and when I replaced mine, it eliminated all remaining noise at startup. The valve itself is replaceable, $30 vs about $6, but I like the shiny new cap, lol.
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