2014 CX5 2.5L timing knock

[RMazda]

Hi all,

I have a 2014 Mazda CX-5 GT 2.5L. I’ve owned it since new and have done oil changes every 5000km with factory filter and Mobil 1 5w30. The car has 170k km on it and has not had any major issues since I bought it.

Yesterday I noticed a knock when it was idling so I got my wife to bring it up to 2500-3000rpm and the video link is the result of that. Oil level is at the high mark.

I put it on a hoist this morning and removed the serpentine and water pump belt to rule out any of that and the knock remained. A stethoscope says it’s from the timing system somewhere.

I’m not very familiar with the vvt system and am wondering if there’s any easy troubleshooting I can do to narrow down what part I need to change? I have a decent scan tool and I’m pretty sure I can actuate stuff with it. I’m pretty mechanically inclined and am not afraid to tear the engine apart.

Anyone here ever deal with this?

Cx-5 knock

youtu.be

 

[cz5gt]

The timing chain plus a plastic guide at the top, the chain tensioner and the cam vvti controller motor are on that side of the engine. Hard to tell from the sound what that may be.
Is it in the upper area?

 

[RMazda]

The timing chain with the tensioners and the cam vvti controller motor are on that side of the engine. Hard to tell from the sound what that may be. Is it in the upper area?

View attachment 309824

 

[RMazda]

It sounds like it’s coming from behind that cover with the sticker on it. Would best bet be to take that off? Or pull the valve cover?

 

[cz5gt]

It sounds like it’s coming from behind that cover with the sticker on it. Would best bet be to take that off? Or pull the valve cover?

that is the

Electric variable valve timing motor/driver

Operates the electric variable valve timing actuator based on the signals from the PCM.

it should be removable without removing the cover but see if the there is enough clerance due to the engine mount

 

[RMazda]

Thank you for the help. I was able to get my scanner on it today and it looks to me like the exhaust side is getting commanded but not moving. I’m going to try and replace the vvt solenoid under the valve cover and see what happens if I don’t see anything else obvious with the valve cover removed. Link to video below.

CX-5 timing desired & actual

youtu.be

 

[RMazda]

So quick update. I Removed the valve cover and the timing chain is slack. This is looking like a VVT failure same as I’ve seen in older Mazda engines on YouTube. I have ordered all new sprockets and a timing chain kit. Will update again once all work is complete. Again this is on a 2014 cx5 gt 2.5L that has has oil changed every 5000km since new with Mobil 1 5w30 and factory filters. 169xxx km on engine. Sad.

 

[edmaz]

You didn't mention anything about a CEL, so there are no codes set (including pending codes)?

 

[RMazda]

You didn't mention anything about a CEL, so there are no codes set (including pending codes)?

That is correct. I have no codes pending or otherwise just the horrible knock which I can only assume is the timing chain slapping.

 

[Jmaz]

Great job troubleshooting and posting the video of readout values. I can't envision how a failed VVT actuator causes slack and slap. The long chain tensioner I could see causing it but I guess that's included in the kit and along with the VVT actuator no doubt needs changed. Not criticizing here, just trying to learn . And yes it's a shame as you said, considering the oil maintenance and miles. Let us know how the repair goes.

 

[RMazda]

Great job troubleshooting and posting the video of readout values. I can't envision how a failed VVT actuator causes slack and slap. The long chain tensioner I could see causing it but I guess that's included in the kit and along with the VVT actuator no doubt needs changed. Not criticizing here, just trying to learn . And yes it's a shame as you said, considering the oil maintenance and miles. Let us know how the repair goes.

I’m not really sure either. It was my understanding that a failed vvt actuator can stretch the chain. I contemplated changing only the timing chain, tensioner and guides as the kit doesn’t come with the sprockets and one of those sprockets (the intake side) was over $400 but I would hate to do all the work and then find out that one of them is also bad. Decided on changing everything under the timing cover. If that doesn’t fix it I guess I’ll find a used engine.

Also a little update about the video, I put my scanner on a 2015 cx5 with the 2.5L to compare what mine is doing. The exhaust cam on the good engine stays at 0 the whole time for all selections, does not move. In my car the readings are all over for the exhaust. Intake cam numbers were about the same. I believe I have an issue with the exhaust vvt actuator on the cam. My oil control valve works fine. Either way I’m changing it all out.

 

[edmaz]

That is correct. I have no codes pending or otherwise just the horrible knock which I can only assume is the timing chain slapping.

I have to be the turd in the punchbowl on this, and say that I don't believe the VVT system would be malfunctioning, without the ECM detecting and flagging that condition by setting a code. I can't explain the readings from your scan tool, however the ECM knows everything that the tool does, and lots of other stuff that's not available via OBD. So with the continuous internal error checking done by the computer, I would put my trust in the absence of a code as proof of no significant timing issue (VVT or otherwise).

And AFA the timing chain being loose enough to flop around and cause a knock, if so IMO it surely would have jumped by now, and trashed the valves.

I hate to say it, but the noise on your vid sounds more like rod knock to me, but of course that's just a guess, and I could be wrong. In your place I'd at least drain and carefully examine the oil before replacing any parts. And a compression test might be in order as well (and possibly followed by a leak down test).

 

[RMazda]

I have to be the turd in the punchbowl on this, and say that I don't believe the VVT system would be malfunctioning, without the ECM detecting and flagging that condition by setting a code. I can't explain the readings from your scan tool, however the ECM knows everything that the tool does, and lots of other stuff that's not available via OBD. So with the continuous internal error checking done by the computer, I would put my trust in the absence of a code as proof of no significant timing issue (VVT or otherwise).

And AFA the timing chain being loose enough to flop around and cause a knock, if so IMO it surely would have jumped by now, and trashed the valves.

I hate to say it, but the noise on your vid sounds more like rod knock to me, but of course that's just a guess, and I could be wrong. In your place I'd at least drain and carefully examine the oil before replacing any parts. And a compression test might be in order as well (and possibly followed by a leak down test).

I don’t disagree with you. The no codes thing has been a pressing concern. I haven’t dropped the oil yet as I didn’t want to have to put fresh oil in to do any more testing. It will be the first thing I do before opening any parts once I get them. I can say the timing chain is very slack between the two cam sprockets however. Not enough to skip a tooth but it is not tight as videos show it should be so even if a bearing is gone there is also an issue on the timing side sadly.

 

[AVC]

Having some experience with VVTI and studying/measuring the Mazda system:

1. From your video, the exhaust cam phaser actual isn't changing or tracking with desired. A loose timing chain would not CAUSE that.

2. You don't leave it at new RPM for long in the video, so it's possible the exhaust cam eventually moves into the +/- range acceptable to the PCM. The PCM allows a number of SECONDS ( 5 to 10?) for the actuator to come within 5 or 6 degrees (as I recall) of desired before it sets a code.

3. An oil control issue to the exhaust VVTI phaser can leave one chamber or both chambers partially empty, which allows the phaser internals to rattle about. It can make a heavy KNOCK when the cam portion of he phaser whacks into the phaser case.

3. If the PCM loses tight phaser control, at engine shutdown it can fail to move the phaser into it's "locked" location; a pin that locks the cam and case of the phaser together. If it fails to lock at shutoff, the phaser case can rotate and leave the chain slack BETWEEN the intake and exhaust phaser sprockets. Never had the 2.5L apart to see whether the head casting prevents the chain from actually jumping up and skipping teeth.

Before going after the chain, I'd first determine whether the oil control solenoid is working, oil passages clogged, or the exhaust phaser developed an internal leak.

 

[RMazda]

Thank you for the info. The oil control valve is verified as good. I ohm’d it and bench tested it. I will have to look closer at the rest of your suggestions. I only took one pic with the valve cover off so sadly that’s all I have for now.

 

[AVC]

You'd have to remove the phaser and disassemble/inspect on the bench to determine a failure, there.

 

[RMazda]

Updating, I know it’s been a long time but I’ve been busy. Anyway you who guessed a bearing were correct. After tearing the timing apart to find nothing wrong I got to the connecting rod bearings and found #1 failed. Waiting on parts again, I’m going to change out all of the con rod bearings and hope for the best. Not sure why it failed, pretty sad.

 

[AVC]

oil starvation is the major cause of bearing failures...probably related to why the valve phaser was unable to follow commanded. I'd chase accessible oil passage with a long pipe cleaner or a length of mono filament (string trimmer line), compressed air... and scrutinize the main oil passages, oil filter boss, etc.

 

[edmaz]

.... Not sure why it failed ...

Yes, with the outstanding oil maintenance you did, it's hard to understand why this happened. I'm sure you found absolutely no sludge anywhere.

I'm curious if you normally extend the warmup idling time during the Winter months, progressively longer depending on the temperature?
I'm not trying to imply it's the likely cause of your engine issue - it's just an idea that I've kicked around trying to explain a weird engine failure history on Canadian Kia Fortes.

How do the journal surfaces look? I hope this bearing replacement works out well for you, but in any case at least it won't cost you very much to get the job done.

 

[Jmaz]

As mentioned by AVC above, oil starvation contributing to bearing failure.
Years ago, I was tangentially involved in a situation where a diesel engine in a piece of construction equipment experienced rod bearing failure. The engine had a good service history and was full of reasonably clean oil when it failed.
The factory rep for the engine manufacturer said the bearing had experienced oil starvation sometime in the past. He went on to say that if the oil pump gets starved for oil due to low level and/ or being operated on a steep slope, the bearings get a shot of air instead and damage can occur quickly but failure not occur for weeks ,maybe longer depending on operating time. He also said it's typically the rod bearings because that is where the greatest relative velocity occurs between two surfaces.
It turned out that particular engine had a shallow oil pan and the contractor was operating on steep slopes. The factory covered the failure under warranty for the contractor.
Just posted this as I found the delayed failure interesting in contrast to a bearing failure that occurs from continuous starvation. Also about the highest relative velocity.