Hi everyone.
Wanted to get some opinions on the state of my CX-5 and see if there are any recommendations on how to address the carbon buildup in the cylinders and get an overall idea of the condition of the engine. It's got 152000 miles on it so I wasn't expecting it to look pristine by any means, but I do want to continue owning it so long as there's no glaring imminent crises.
Background: Bought the car cert-pre-owned with 20k miles. Went on a road trip not long after that and put an extra 20k miles on it. I've been religious about changing oil/filter every 5000-6000 miles and keeping up on maintenance. Around 90k miles started having issues with valve lifter tick, and eventually found a Mazda service bulletin addressing the issue. Took car into a local shop and sure enough, cylinder #4 intake valve lifters were shot. Cylinder #1 not as much , but had all intake valve lifters replaced. No issue since. Ever since then, however, the car has regular instances where after turning off engine after a bout of driving, especially in the winter, and restarting it after 5-10 mins, it'll be really rough on startup like it's only running on 3 cylinders. I suspect that even though I fixed the valve lifters there's still some residual effects and carbon built up as a result. Ever since I got this car I knew that carbon buildup would eventually be an issue, and I'm currently trying to find a local place that'll do walnut blasting on a Mazda. No luck so far.
I wanted to scope the innards of the cylinder to get a sense of the condition of my car and see if it's fixable in terms of cleaning off the carbon and to make sure there were no glaring issues.
I've included pictures after scoping the cylinders.
Quick summary; All of the injectors are pretty fouled up with carbon. The intake valves also have a bit of carbon buildup on the edges, especially cylinders #1, #4 which are the deactivation cylinders. The pistons themselves are a bit rough in some spots with clear bits of carbon chunks on them and some areas with a wet sheen to them. I'm also concerned about the gasket between the block and head, since in some photos it looks degraded, but I can't tell if that' just built up carbon.
Question 1: What would be the best way to clean the injectors? Removal/ultrasonic cleaning?
Question 2: Is there an effective way to clean the carbon inside the cylinders and on the pistons? I'm not sure what to think of some of these fuel additive cleaners like Techron or CRC valve cleaner.
Question 3: If fuel additives aren't an option, is there a way to directly clean the tops of the pistons? Like flooding the cylinder with some kind of solvent and then sucking out the fluid through the spark plug port? I don't want to have to remove the head.
Question 4: For 152000 miles, what's your take on the overall appearance?
I'm open to any info. I just want to keep this car a while longer and do what I can to keep the innards in good condition. Overall, the car has been super reliable. Other than that issue with the valve lifters, it's been solid. Kudos to Mazda for making a car that's easy to service. It's got a fricken dipstick for the transmission after all! Which I changed at 90k miles.
Wanted to get some opinions on the state of my CX-5 and see if there are any recommendations on how to address the carbon buildup in the cylinders and get an overall idea of the condition of the engine. It's got 152000 miles on it so I wasn't expecting it to look pristine by any means, but I do want to continue owning it so long as there's no glaring imminent crises.
Background: Bought the car cert-pre-owned with 20k miles. Went on a road trip not long after that and put an extra 20k miles on it. I've been religious about changing oil/filter every 5000-6000 miles and keeping up on maintenance. Around 90k miles started having issues with valve lifter tick, and eventually found a Mazda service bulletin addressing the issue. Took car into a local shop and sure enough, cylinder #4 intake valve lifters were shot. Cylinder #1 not as much , but had all intake valve lifters replaced. No issue since. Ever since then, however, the car has regular instances where after turning off engine after a bout of driving, especially in the winter, and restarting it after 5-10 mins, it'll be really rough on startup like it's only running on 3 cylinders. I suspect that even though I fixed the valve lifters there's still some residual effects and carbon built up as a result. Ever since I got this car I knew that carbon buildup would eventually be an issue, and I'm currently trying to find a local place that'll do walnut blasting on a Mazda. No luck so far.
I wanted to scope the innards of the cylinder to get a sense of the condition of my car and see if it's fixable in terms of cleaning off the carbon and to make sure there were no glaring issues.
I've included pictures after scoping the cylinders.
Quick summary; All of the injectors are pretty fouled up with carbon. The intake valves also have a bit of carbon buildup on the edges, especially cylinders #1, #4 which are the deactivation cylinders. The pistons themselves are a bit rough in some spots with clear bits of carbon chunks on them and some areas with a wet sheen to them. I'm also concerned about the gasket between the block and head, since in some photos it looks degraded, but I can't tell if that' just built up carbon.
Question 1: What would be the best way to clean the injectors? Removal/ultrasonic cleaning?
Question 2: Is there an effective way to clean the carbon inside the cylinders and on the pistons? I'm not sure what to think of some of these fuel additive cleaners like Techron or CRC valve cleaner.
Question 3: If fuel additives aren't an option, is there a way to directly clean the tops of the pistons? Like flooding the cylinder with some kind of solvent and then sucking out the fluid through the spark plug port? I don't want to have to remove the head.
Question 4: For 152000 miles, what's your take on the overall appearance?
I'm open to any info. I just want to keep this car a while longer and do what I can to keep the innards in good condition. Overall, the car has been super reliable. Other than that issue with the valve lifters, it's been solid. Kudos to Mazda for making a car that's easy to service. It's got a fricken dipstick for the transmission after all! Which I changed at 90k miles.
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