CX5 Diesel engine issues
Junior Member
Joined: Jun 2020
Posts: 4
Likes: 0
From: Portland, OR
I am the owner of a U.S. 2019 Mazda CX-5 Diesel. It’s currently in the repair shop (again) for check engine light. So far the shop has replaced the catalytic converter, and is now replacing the PCM module. The car has been lightly used (low mileage) so all work so far has been under warranty. I am planning on replacing the car with the hybrid CX-5 when it comes out later this year.
Junior Member
Joined: Apr 2025
Posts: 1
Likes: 0
From: Kyogle NSW Australia
Like many others on here, I wish I had found this forum before buying my Mazda 6 2.2L diesel. I have solved most problems, however there is one I am hoping someone in the brains trust here can help me with.
A brief history for background understanding.
I am third owner. Purchased at 66,000Km
Previous receipts included - 52k Km replace faulty exhaust pressure sensor and 60,800 Km Fuel hose recall
Had a great run then until 117,000 Km with low oil pressure warning resulting in Mazda Springwood repairing injector seal and oil pump cleanout under warranty
Then at 132,000 Km, a coolant pressure test reveiled a possible blown head gasket or worse. Mazda estimated repair costs of $8000 to $12000. Money I did not have. They said it was not a warranty issue.
Unfortunately I did not find this forum before resigning myself to fixing it myself. However, long story made short, I managed to do it the hard way without a hoist, leaving the engine in place.
In some ways I'm pleased I did it myself as I found 3 valve rockers with worn sockets, which I'd suggest was from the carbon laden oil, due to the earlier injector seal leakage that Mazda fixed. Thankfully the cams and bearings were still in very good condition.
The head gasket was definately the problem, but luckily the head was not warped or cracked, although the machine shop skimmed it to be sure.
During the reassembly, I cleaned all the carbon from the intake ports and EGR bits and tried to blow out the Cat Converter with compressed air as best I could.
I have clocked up almost 20,000 Km since with no problems, except one, and this is where I am hoping someone can shed some light on what might be causing it. The "DPF Inspection Required" warning and engine light comes on and stays on until cancelled out, but when put on the test computer, doesn't pinpoint the cause.
I have had it tested and reset 6 or more times now by my local country mechanic and a specialist diesel workshop in town. There is no noticible reduction in engine performance when the warning is on, although the dipstick oil level increases if not reset for a 2000 Km period.
After a reset it typically stays off for 250 to 350km and comes on when the computer changes down a gear to help slow the car. The car does mainly country miles - 2 to 3 hour drives and has had a forced decarb burn done.
Any clues anyone?
A brief history for background understanding.
I am third owner. Purchased at 66,000Km
Previous receipts included - 52k Km replace faulty exhaust pressure sensor and 60,800 Km Fuel hose recall
Had a great run then until 117,000 Km with low oil pressure warning resulting in Mazda Springwood repairing injector seal and oil pump cleanout under warranty
Then at 132,000 Km, a coolant pressure test reveiled a possible blown head gasket or worse. Mazda estimated repair costs of $8000 to $12000. Money I did not have. They said it was not a warranty issue.
Unfortunately I did not find this forum before resigning myself to fixing it myself. However, long story made short, I managed to do it the hard way without a hoist, leaving the engine in place.
In some ways I'm pleased I did it myself as I found 3 valve rockers with worn sockets, which I'd suggest was from the carbon laden oil, due to the earlier injector seal leakage that Mazda fixed. Thankfully the cams and bearings were still in very good condition.
The head gasket was definately the problem, but luckily the head was not warped or cracked, although the machine shop skimmed it to be sure.
During the reassembly, I cleaned all the carbon from the intake ports and EGR bits and tried to blow out the Cat Converter with compressed air as best I could.
I have clocked up almost 20,000 Km since with no problems, except one, and this is where I am hoping someone can shed some light on what might be causing it. The "DPF Inspection Required" warning and engine light comes on and stays on until cancelled out, but when put on the test computer, doesn't pinpoint the cause.
I have had it tested and reset 6 or more times now by my local country mechanic and a specialist diesel workshop in town. There is no noticible reduction in engine performance when the warning is on, although the dipstick oil level increases if not reset for a 2000 Km period.
After a reset it typically stays off for 250 to 350km and comes on when the computer changes down a gear to help slow the car. The car does mainly country miles - 2 to 3 hour drives and has had a forced decarb burn done.
Any clues anyone?
Thread
Thread Starter
Forum
Replies
Last Post
