Massive oil leak on passenger side from under-shield, smoking from engine bay

[tth42]

Noticed a strong smell of burning oil and rubber through the air vents today, pulled over and opened my hood to a plume of smoldering smoke and a pool of oil on the ground. After a look underneath, everything on the passenger side is absolutely covered in oil. No oil pressure/level lights or unusual performance, but it’s been parked for now. Did I get cursed by the Skyactiv 2.5 NA cylinder head issue? (yes my VIN is included in the models with cylinder deactivation).

2018 CX-5 2.5 NA 109k miles

 

[Jmaz]

I assume you checked to see if the oil filter is tight since it's on the passenger side of the car and on the bottom side of the car where the oil is.

 

[tth42]

I assume you checked to see if the oil filter is tight since it's on the passenger side of the car and on the bottom side of the car where the oil is.

Yes, both the filter and drain plug are secure and torqued appropriately.

 

[stickerbush]

That sucks. Are you going to take it to a mechanic or diagnose yourself?

 

[cz5gt]

Remove the engine decorative cover then try to pinpoint where the leak started. Look back at near the exhaust (this is where the head cracks) and on the engine side/passenger side where it has a cover which is known to leak but not that severe.

Try to figure if oil is leaking from top down or somewhere down.

 

[tth42]

Remove the engine decorative cover then try to pinpoint where the leak started. Look back at near the exhaust (this is where the head cracks) and on the engine side/passenger side where it has a cover which is known to leak but not that severe.

Try to figure if oil is leaking from top down or somewhere down.

Haven’t gotten the cover off yet, but I took a look again today in daylight and could see a drip every 3-5 seconds coming from the back of the engine near the top. Will have to take the cover off to see the exact source, but I have a bad feeling that it’s dripping right at the head.

 

[Jmaz]

Haven’t gotten the cover off yet, but I took a look again today in daylight and could see a drip every 3-5 seconds coming from the back of the engine near the top. Will have to take the cover off to see the exact source, but I have a bad feeling that it’s dripping right at the head.

That's not just a leak but a leak with definitely some pressure behind it. Barring a cracked head, the only 2 other things I can think of is if the head gasket blew outward from an oil passage area or maybe related to the VVT actuator for the exhaust camshaft which uses oil pressure and is towards the rear side of the engine, but these don't seem too likely.

 

[tth42]

most likely it could be the head crack issue. that is very bad but the good at least is that Mazda extended the warranty to 10yrs and 100k+ miles.

If this is true, that would be awesome. Are you able to cite a source on this? I did some research and it looks like this only applies to the CX-9 and CX-5 with turbo, not the NA versions.

 

[Lazy2.5]

Why don't you take the engine cover off to see where it's coming from, first?

Could be the valve cover gasket? Though I believe those tend to be slow, gradual leaks.

 

[sm1ke]

If this is true, that would be awesome. Are you able to cite a source on this? I did some research and it looks like this only applies to the CX-9 and CX-5 with turbo, not the NA versions.

There are two separate cylinder head cracking issues.

The one for the 2.5T involves a cylinder head crack near the exhaust manifold, and usually results in an external coolant leak. The one for the 2.5 N/A with CD is also a cylinder head crack, but it results in an external oil leak.

The 2.5T's cylinder head was redesigned in 2021, so only the 2016-2020 cars with the 2.5T are prone to the coolant leak. The 2.5 N/A with CD cylinder head has not been retooled or revised.

 

[cz5gt]

Yes. Totally forgot the Turbo had simillar issue but separate than the non turbo engine. The warranty extension then may be for the Turbo.

 

[N7turbo]

The warranty extension is only for the 2.5T.

 

[tth42]

That's not just a leak but a leak with definitely some pressure behind it. Barring a cracked head, the only 2 other things I can think of is if the head gasket blew outward from an oil passage area or maybe related to the VVT actuator for the exhaust camshaft which uses oil pressure and is towards the rear side of the engine, but these don't seem too likely.

Can confirm the head is cracked. Once I was able to see the back of the head, I noticed a very quick stream of dripping oil coming from either cylinder 2 or 3 straight off the back of the head. Very disappointed to see this happened to my CX-5. I've been meticulous about maintenance, but from what I read, the issue is a structural defect on the naturally aspirated models that had their heads modified for cylinder deactivation. I spoke with a Mazda dealer who confirmed that the naturally aspirated models are not under the extended warranty, so it's going to be an out of pocket repair.

 

[N7turbo]

And I think that's ridiculous. It absolutely should be treated the same as the 2.5T. I'm sorry the dice didn't land in your favor.

 

[sm1ke]

Can confirm the head is cracked. Once I was able to see the back of the head, I noticed a very quick stream of dripping oil coming from either cylinder 2 or 3 straight off the back of the head. Very disappointed to see this happened to my CX-5. I've been meticulous about maintenance, but from what I read, the issue is a structural defect on the naturally aspirated models that had their heads modified for cylinder deactivation. I spoke with a Mazda dealer who confirmed that the naturally aspirated models are not under the extended warranty, so it's going to be an out of pocket repair.

All is not lost (yet). If it's worth your time and effort, I would reach out to Mazda Corporate to voice your concerns and disappointment and pursue a goodwill repair. There is a cracked cylinder head "megathread" for the 2.5 N/A, here's a link. It's 31 pages long, but there's quite a bit of discussion surrounding the issue, along with pictures and related TSBs. Using this information, you may be able to plead your case to Mazda Corporate to ask for a full or partial goodwill repair, based on how well you treated the vehicle and this purported manufacturing defect. Edited to add: Keep a cool, level head. Be polite, but firm. Use reason and logic to argue your case. Patience and persistence go a long way - depending on the rep, you may have to wear them down or keep trying with a different rep, and you may need to escalate to their management team.

Keep all your maintenance records handy, and be prepared for them to ask you to bring the car to your dealer for a diagnosis that you'll have to pay for - this is so they can have their own techs confirm the issue.

Worst case scenario, you fix it out of pocket, but you can just source a used cylinder head and take it to an independent engine shop to do the work, providing Mazda's TSB for guidance if they need it. This would cut down the costs significantly, and wouldn't be much different from a dealer installing a brand new head since as far as we know, Mazda hasn't revised the N/A head to address this issue.

 

[Lazy2.5]

I would pursue this with corporate very persistently.

 

[Nevada CX5]

I got Mazda corporate to contribute $1500 and the dealer another $500 since I had used them for some service.

Good luck, this crap should never happen!

 

[Nevada CX5]

I also filed a complaint with the NHTSB citing a potential fire hazard due to the leaking oil. Hoping for a recall.