2018 CX-5 110k mi Valve Lifter Tick Camshaft Damage? (w/ pics)

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I'm still wondering why only the one cylinder would be suffering from carbon buildup more than the other cylinders. ...
A result of the bad lifter IMO.

.... When I removed the intake manifold to inspect the valves there was some oil in the manifold. Is that typical for a car with 110k miles on it?
A bit of oil in there wouldn't be unusual at all.
 
I hope the new lifter will at least prevent the problem from getting worse
Yes, the new lifter should correct the problem, but you're going to have to decide how to proceed with what's already in there. You could try chemical cleaning and hope that's good enough. No idea how that will work long term.

Also, I was not fully awake last night, and this morning it hit me that those compression numbers are all way too high ("normal" is around 165 PSI). I suspect that your mechanic didn't remove the fuel pump relay before doing the test. That relay is not in the ER fuse box, and he might not have been aware that the FP relay is in a separate, small box on the passenger side of the vehicle. But that doesn't change the fact that #4 is so much higher than the rest of them, so the result of the test is probably still valid in that sense.
 
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Yes, the new lifter should correct the problem, but you're going to have to decide how to proceed with what's already in there. You could try chemical cleaning and hope that's good enough. No idea how
Yeah this is what was keeping me up at night; even if the main problem is corrected the aftermath still lingers and I don't know if what's already in there would clear out on its own over time. My gut tells me no. And now if I continue to drive with it it'll always be a source of anxiety in the back of my mind knowing that there is a potential time bomb in one of the cylinders.

It's frustrating that this all happened after the extended warranty. Technically I started noticing and documenting the valve lifter tick at around 93000 miles, but then when the weather warmed up it started to become less frequent and then eventually go away in the really warm months. All this trouble from a tiny component part of a system designed to save a miniscule amount of fuel and money. I wonder if this would ever justify a class action lawsuit.

Volkswagen and Audi had that lawsuit where the timing chain tensioner was failing on their 2.0T engines(my Dad's was one of them), thus causing catastrophic engine damage. It seems like this case wouldn't be too far off; an improperly designed piece, which Mazda admits is poorly designed given they issued the TSB and redesigned it, that leads to unnatural engine wear and performance that can cause the engine to fail prematurely in the future. After all, if one of the effects of this whole valve lifter issue is early onset blown gaskets due to abnormally high cylinder pressure resulting from the lifters then one might think that could make a case.
 
... I wonder if this would ever justify a class action lawsuit. ...
I've never been a part of one of those things, but everything I've read about them says that the lawyers collect the $$$ and the litigants get $hit. Perhaps there are exceptions to that - IDK.

Just an FYI that I hit a couple of keys by mistake, which sent my last post in before I was finished. I included some info about the compression test - no big deal, but you might want to discuss it with your mechanic.
 
Yeah this is what was keeping me up at night; even if the main problem is corrected the aftermath still lingers and I don't know if what's already in there would clear out on its own over time. My gut tells me no. And now if I continue to drive with it it'll always be a source of anxiety in the back of my mind knowing that there is a potential time bomb in one of the cylinders.

It's frustrating that this all happened after the extended warranty. Technically I started noticing and documenting the valve lifter tick at around 93000 miles, but then when the weather warmed up it started to become less frequent and then eventually go away in the really warm months. All this trouble from a tiny component part of a system designed to save a miniscule amount of fuel and money. I wonder if this would ever justify a class action lawsuit.

Volkswagen and Audi had that lawsuit where the timing chain tensioner was failing on their 2.0T engines(my Dad's was one of them), thus causing catastrophic engine damage. It seems like this case wouldn't be too far off; an improperly designed piece, which Mazda admits is poorly designed given they issued the TSB and redesigned it, that leads to unnatural engine wear and performance that can cause the engine to fail prematurely in the future. After all, if one of the effects of this whole valve lifter issue is early onset blown gaskets due to abnormally high cylinder pressure resulting from the lifters then one might think that could make a case.
I'm curious why you didn't take it to the dealer at 93k miles when it was still under the 100k CPO powertrain warranty
 
I've never been a part of one of those things, but everything I've read about them says that the lawyers collect the $$$ and the litigants get $hit. Perhaps there are exceptions to that - IDK.

Just an FYI that I hit a couple of keys by mistake, which sent my last post in before I was finished. I included some info about the compression test - no big deal, but you might want to discuss it with your mechanic.
No worries.

Also, I just thought of something that might explain the high cylinder pressure, aside from carbon buildup on the piston; I remember watching a video years ago describing how the 2.5 engine in the 2017/2018 CX-5 works. If I remember correctly, the intake valves are designed to be open for a moment during the exhaust stroke thus pumping some of the burned gasses back into the intake runners. I think the reason was to do with preheating the incoming air. But if this is the case, and the intake valves are meant to be open during this part of the cycle then the broken HLA could be the cause of the higher pressure - that intake valve is not opening or is opening very little, thus the gasses that were meant to escape back into the intake runners can't and are instead getting trapped in the cylinder leading to higher pressure.

Correct me if I'm wrong about the exhaust gasses going back into the intake, but I swear I remember watching a video describing the process. I also am certain I remember thinking that it was a terrible idea to pump burned gasses back into the intake.
 
Automakers have been doing all sorts of things relative to recycling gases for years now, and it's hard to keep up with everything on that front. I certainly don't know what Mazda's complete SKYACTIV strategy for recycling gases is, so all I can say is that what you read may, or may not be true.

However, that 165 PSI number (at 350 RPM) for "normal/standard" compression comes right from the Mazda FSM. So any effect that recycling of gases has on compression is just one of the many factors contributing to that 165 PSI spec. The only extra informational statement that's made in the FSM write-up is this one: "Because the SKYACTIV-G retards the intake valve closing timing, compression is low" I assume that "is low" actually means something like "is lower than most other engines"

Also, removal of the FP relay/fuel pressure relief is a prerequisite step specified in the FSM compression test procedure, and seems to be the only factor that could cause higher-than-normal compression test results, aside from a defective tool. As I said previously, the higher-than-normal-spec compression readings probably are not going to make a difference in the diagnosis, which comes from the extra high reading from #4.
 
Automakers have been doing all sorts of things relative to recycling gases for years now, and it's hard to keep up with everything on that front. I certainly don't know what Mazda's complete SKYACTIV strategy for recycling gases is, so all I can say is that what you read may, or may not be true.

However, that 165 PSI number (at 350 RPM) for "normal/standard" compression comes right from the Mazda FSM. So any effect that recycling of gases has on compression is just one of the many factors contributing to that 165 PSI spec. The only extra informational statement that's made in the FSM write-up is this one: "Because the SKYACTIV-G retards the intake valve closing timing, compression is low" I assume that "is low" actually means something like "is lower than most other engines"

Also, removal of the FP relay/fuel pressure relief is a prerequisite step specified in the FSM compression test procedure, and seems to be the only factor that could cause higher-than-normal compression test results, aside from a defective tool. As I said previously, the higher-than-normal-spec compression readings probably are not going to make a difference in the diagnosis, which comes from the extra high reading from #4.
I just found the service manual section describing the miller cycle of the engine as well as that line you typed in bold. By my read, it is the case that the intake valve is indeed held open for a period during the compression stroke thus allowing the gasses to flow back out the intake port. So if one of the intake valves is remaining closed, or nearly closed due to the broken HLA then that would definitely be causing higher pressure in the cylinder. At least I sure as hell hope that's why. I'm hoping it's that instead of carbon buildup on the piston.
 
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. Compression pressure for cyls 1-3 was about 200 psi, but cyl 4 was at 260 psi. What to make of this? This was also the cylinder that had the dirtiest intake valves with lots of carbon build up and the wettish looking spark plug. Oil entering cylinder 4 somehow?

A bit late to comment, but here it is:

1. If a lifter is weak/defective (usually excess leak down) it changes the effective valve timing on #4; i.e unlike cylinders 1, 2, 3 that bleed off compression during highly retarded intake cam cranking. Thus higher cranking compression on #4. Unless #4 is also suffering a bad injector, there's no reason it would be more or less flodded than other cylinders, if the tech forgot to disable injectors. Did the mechanic do an "after" repair compression test?

2. From my own valve cleaning experience, cyl 4 and to some degree #3 have more valve carbon buildup than #1 or #2. Likely the oil mist flow in the intake manifold runners is heavier for those cyl. Also possible valves on that end of the head run slightly different temp than 1 and 2 (location of radiator hose takeoff on the block). In any case, I doubt relevant to your lifter issue.
 
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A bit late to comment, but here it is:

1. If a lifter is weak/defective (usually excess leak down) it changes the effective valve timing; i.e unlike other cylinders that bleed off compression during highly retarded intake cam cranking. Thus higher cranking compression. Unless #4 is also suffering a bad injector, there's no reason it would be more or less flodded than other cylinders, if the tech forgot to disable injectors. Did the mechanic do an "after" repair compression test?

2. From my own valve cleaning experience, cyl 4 and to some degree #3 have more valve carbon buildup than #1 or #2. Likely the oil mist flow in the intake manifold runners is heavier for those cyl. Also possible valves on that end of the head run slightly different temp than 1 and 2 (location of radiator hose takeoff on the block). In any case, I doubt relevant to your lifter issue.
What you say about the defective lifters changing the effective valve timing makes me think it also explains these values I got when plugging in my diagnostic tool the other week...
20221124_130731.jpg

At first, I wasn't sure exactly how to interpret this. I first thought it meant the camshaft was somehow rotated an extra 270 deg out of phase or something, but that obviously wouldn't make sense since for that many degrees of rotation the pistons and valves would've collided. Based on your explanation, could the defective valve lifter cause the Test Value to be that far out of spec?

Also, what exactly is this VVT Monitor Bank 1 test measuring? When I saw degrees I immediately thought rotation, but I'm not sure exactly how it applies in this context.
 
The PCM would have no way of measuring or inferring the position of individual valves; i.e detecting if a lifter failed. It only knows the position of the cams in relation to the crank. As for the scan tool snapshot, not sure how to interpret 655.32 degrees. Might be bogus data (not unusual with vehicle specific PID's using a non-OEM scan tool).
 
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2. From my own valve cleaning experience, cyl 4 and to some degree #3 have more valve carbon buildup than #1 or #2. Likely the oil mist flow in the intake manifold runners is heavier for those cyl. Also possible valves on that end of the head run slightly different temp than 1 and 2 (location of radiator hose takeoff on the block). In any case, I doubt relevant to your lifter issue.
Unless I'm somehow misinterpreting what you wrote, you're dismissing the lifter issue as contributing to the higher compression in #4, and attributing it to the design and operating characteristics of the engine. But that would mean that most/many of these engines with around 110K miles would also have #4 reading 20%+ higher compression than the other cylinders. Is that really what you believe?
 
The PCM would have no way of measuring or inferring the position of individual valves; i.e detecting if a lifter failed. It only knows the position of the cams in relation to the crank. As for the scan tool snapshot, not sure how to interpret 655.32 degrees. Might be bogus data (not unusual with vehicle specific PID's using a non-OEM scan tool).
The bogus data is very possible. The tool is technically for mercedes-benz, but it was all I had. I do often have trouble with it maintaining connection when trying to view live data as well. What's more, a few weeks later I ran the diagnostic again. With the car ignition on, but engine NOT running and got this...
20220310_151942.jpg

After turning on the engine this Test Value stayed the same as when the engine was not running. I also disconnected and reconnected the tool, in case it was just continuing to display the value measured before the engine was running, and it still showed this value of 0.22 deg. This really threw me for a loop as it now seemed like whatever was rotated out of spec was now 14 deg within being in spec. Later, it returned to showing a Test Value of 655.32 deg again.

Of course, as you said, could be bogus data since it's a non-oem scanner tool.
 
Yes, my bad, I missed your point because I've been totally focused on the higher compression, and didn't pick up that you were talking about the other stuff.
 
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Yes, my bad, I missed your point because I've been totally focused on the higher compression, and didn't pick up that you were talking about the other stuff.
I edited my post to be clearer, hopefully.
 
I edited my post to be clearer, hopefully.
Nice of you to take the time to do that, but I'm sure that anyone who is not as single-minded as I am (was) about this, would have done fine with what you originally posted.
 
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