Engine Light went on ...

My Mazda CX-9 [2015 and 85k miles] engine light went on. I noticed that coolant was empty. I filled it and the light went off but the next day it was on again.
I took to the dealership and they say it needs a new engine and it costs $11,000 (nailbyt)
Does that make sense? I had done all the scheduled maintenance and had no problem with the car till now. What could have been the problem and should I show it to another dealership or repair shop?
 
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2017 CX-9 Touring
Sounds like a water pump failure... what happen is the water pump failed caused the coolant to leak internally while driving. Coolant leak and got mixed with motor oil. You may want to look into getting used engine from total loss vehicle for cheaper price.

Good luck.
 
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2010 CX-9 GT
My Mazda CX-9 [2015 and 85k miles] engine light went on. I noticed that coolant was empty. I filled it and the light went off but the next day it was on again.
I took to the dealership and they say it needs a new engine and it costs $11,000 (nailbyt)
Does that make sense? I had done all the scheduled maintenance and had no problem with the car till now. What could have been the problem and should I show it to another dealership or repair shop?

When you say the coolant was empty, what do you mean? The overflow bottle or the entire system?

If you added water and it disappeared but didn't see any on the ground, that's pointing to a head gasket or water pump failure. I'd be hoping for a gasket failure, but, unfortunately, the water pump is a known design issue with these cars. The water pump is driven by the timing chain. The pump can leak through its input shaft/bearings, letting water into the timing chain area, which is lubricated by engine oil. The water mixes with the oil and eventually destroys the engine.

Did the car still run normally when you took it to the dealer? Did you happen to check your oil at any point when this started happening?

IF it is the water pump, that's a $3k-4k repair job. However, if enough water gets into the oil, it destroys the bearings, and it's new engine time.
 
Thanks for the replies.

Update is that I talked again with the dealer and they found no leak an no sign of water and oil mixing -not sure how they tested it. So they say they dont know why the water was empty. and I think it was only the overflow bottle was empty.

Car was driving OK when I took it to the dealer. The test shows TDC error P0016. Dealer changed oil and filter did crank case cleaning, and said the pump is OK. They initially quoted to inspect the timing system for $560, but later after changing the oil and cleaning they thought there is no point. Not sure how they came to this conclusion.

I wanted to get another person opinion, so I drove it to another nearby garage, only 1 mile from the dealer. Still, it was driving normally at this short distance. They said, since the car is driving normally it is probably a faulty sensor, and they would replace it with $300 and while they do that they can check the timing system also if there is something wrong with that.

Any chance it could be only the sensor?
 
As I precaution, I would look to confirm that the water pump seals are ok (to prevent the very costly water pump problem mentioned above). I don*t think a timing mechanism inspection would give much indication, since the issue is usually behind the mechanism. (The chain drives the water pump on the front, but it leaks *behind* the pump directly into the engine oil). A simple thing to do is to get your oil analyzed to confirm if there is coolant. There also wouldn*t be any leaks, because it leaks directly into the engine.

If you google water pump problem for ford 3.5 (3.7) you will find a lot of information on this known (but costly) problem. Better to catch it early if it is a water pump problem because the repairs are costly if it is.
 
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2010 CX-9 GT
Thanks for the replies.

Update is that I talked again with the dealer and they found no leak an no sign of water and oil mixing -not sure how they tested it. So they say they dont know why the water was empty. and I think it was only the overflow bottle was empty.

Car was driving OK when I took it to the dealer. The test shows TDC error P0016. Dealer changed oil and filter did crank case cleaning, and said the pump is OK. They initially quoted to inspect the timing system for $560, but later after changing the oil and cleaning they thought there is no point. Not sure how they came to this conclusion.

I wanted to get another person opinion, so I drove it to another nearby garage, only 1 mile from the dealer. Still, it was driving normally at this short distance. They said, since the car is driving normally it is probably a faulty sensor, and they would replace it with $300 and while they do that they can check the timing system also if there is something wrong with that.

Any chance it could be only the sensor?

Just so we are clear here, is the following timeline correct?
1. You took it to the dealer because the light came on.
2. They read the code, found P0016.
3. They changed the oil and filter and cleaned the crankcase and recommended a timing inspection.
4. After changing the oil, they said "don't bother with the timing, you need a new engine"

I'm having trouble with #3 and #4 if they didn't find any water in the crankcase. It is OBVIOUS when water gets into oil. The only way their actions make any sense is if they drained the oil and it had water in it, yet you say that they didn't find any sign of water in the oil? There's no reason to clean the crankcase unless they found water.

To me, it sounds like they made a quick diagnosis of the problem initially - maybe they looked into the overflow and didn't see any sign of oil and coolant mixing. However, they changed their minds after seeing the engine oil when it came out. Did they save a sample of the oil to show you? Is the water level in the overflow dropping as you continue to drive it?

P0016 is a camshaft/crankshaft timing error. The ECU thinks the camshaft(s) in bank A are rotated out of their ideal position relative to the crankshaft. Sometimes this can be caused by the variable valve timing actuators going bad (which has happened to others on this forum) or a bad sensor. However, these VVT actuators use oil pressure to run, so if water gets in the oil, the VVT mechanisms can malfunction. I recall a few threads on this forum where a P0016 code ended up being related to water in the oil.

You need to get the story straight from the dealer. If they found water in the oil, I understand why they said you need a new engine.
 
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Just so we are clear here, is the following timeline correct?
1. You took it to the dealer because the light came on.
2. They read the code, found P0016.
3. They changed the oil and filter and cleaned the crankcase and recommended a timing inspection.
4. After changing the oil, they said "don't bother with the timing, you need a new engine"

I'm having trouble with #3 and #4 if they didn't find any water in the crankcase. It is OBVIOUS when water gets into oil. The only way their actions make any sense is if they drained the oil and it had water in it, yet you say that they didn't find any sign of water in the oil? There's no reason to clean the crankcase unless they found water.

To me, it sounds like they made a quick diagnosis of the problem initially - maybe they looked into the overflow and didn't see any sign of oil and coolant mixing. However, they changed their minds after seeing the engine oil when it came out. Did they save a sample of the oil to show you? Is the water level in the overflow dropping as you continue to drive it?

P0016 is a camshaft/crankshaft timing error. The ECU thinks the camshaft(s) in bank A are rotated out of their ideal position relative to the crankshaft. Sometimes this can be caused by the variable valve timing actuators going bad (which has happened to others on this forum) or a bad sensor. However, these VVT actuators use oil pressure to run, so if water gets in the oil, the VVT mechanisms can malfunction. I recall a few threads on this forum where a P0016 code ended up being related to water in the oil.

You need to get the story straight from the dealer. If they found water in the oil, I understand why they said you need a new engine.


Thanks again for the reply. Yes, the timeline is correct.

They did drain the oil, at least they did not tell me if there was water in the oil - in their paperwork they mention specifically that they did not see a sign of mixing oil and water, how accurate their test was is difficult for me to judge.

My feeling was they they were trying to push me for a trade-in and get a new CX-9 that I cannot do at the moment.

Anyway, if they found water in oil ---> I need a new engine
If they did not find water in oil, not clear why they say why it needs a new engine, correct?

The car is at a different garage now to change the sensor, check the timing, and pressure test for the leakage. When I drive, I dont see noticeable change of water level, may pressure test can tell if there is leakage directly into engine? Anything else you recommend the garage should look into or try?
 
As I precaution, I would look to confirm that the water pump seals are ok (to prevent the very costly water pump problem mentioned above). I don*t think a timing mechanism inspection would give much indication, since the issue is usually behind the mechanism. (The chain drives the water pump on the front, but it leaks *behind* the pump directly into the engine oil). A simple thing to do is to get your oil analyzed to confirm if there is coolant. There also wouldn*t be any leaks, because it leaks directly into the engine.

If you google water pump problem for ford 3.5 (3.7) you will find a lot of information on this known (but costly) problem. Better to catch it early if it is a water pump problem because the repairs are costly if it is.

Thanks. So pressure testing for leak cannot tell if water is leaking into engine and the only way is to analyze the oil? Is it a normal test that repair shops do?
 
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2012 Mazda CX-9 Grand Touring FWD
So, if this were my vehicle I would: Top off both oil and coolant (with Mazda coolant) and monitor them very closely. If the coolant level is going down and the oil level is going up: most likely water pump BUT could be another internal leak. Watch under the vehicle carefully to see if there is an external leak. See what happens. If it all seems normal, I would run an oil analysis (such as Blackstone labs) to see if there is any slight amounts of coolant in the oil. Keep us posted.
 
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Mazda CX-9 Grand Touring 2016
the water pump is a known design issue with these cars. The water pump is driven by the timing chain. The pump can leak through its input shaft/bearings, letting water into the timing chain area, which is lubricated by engine oil. The water mixes with the oil and eventually destroys the engine.
(a) Have a new water pump installed.
--or--
(b) Top off the fluids and trade-in the car to a Mazda dealer.

The pressure test should be able to tell if the leak continues, but engine heat causes things to expand and move. An oil analysis ($28 DIY...https://www.blackstone-labs.com/tests/standard-analysis/ Will show if there is coolant in the oil at the time the oil sample is taken and if there are excessive wear metals in the oil showing engine damage.

I took to the dealership and they say it needs a new engine
The service writer is NOT an expert on everything automotive. The service writer is a commission salesman. He properly should have charged you a diagnostic fee and let a technician investigate your problem. Only then would he have known what he is talking about. A commission on an $11,000 job would be great--for him. For you to put $11k into a car that is worth only $11k isn't so great for you.
 
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Thanks for the comments again. Here is an update:
The repair shop (not dealer) changed the sensor, the engine light went off, they took it for a test drive. He said that although the light was off he felt something was wrong and took it back, checked the engine and found that there is a significant amount of oil and coolant mixing visible, the oil color shows that there is water in it and that the coolant level had dropped. The leak according to him is through engine and not directly under it.

He said that this has happened because of head gasket failure when the engine overheated. This agrees well with comments you all have given.

So now, he is quoting $3800 to do the repairs which includes water pump replacement - with one year of parts and labor warranty. Would this make sense to do? I am OK to pay that if I know that the car would be functional after the repair and there is not permanent damage to other parts of the engine. According to him, this is unlikely as he didn't feel that when he was test driving it.

Any suggestions?
 
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2010 CX-9 GT
Thanks for the comments again. Here is an update:
The repair shop (not dealer) changed the sensor, the engine light went off, they took it for a test drive. He said that although the light was off he felt something was wrong and took it back, checked the engine and found that there is a significant amount of oil and coolant mixing visible, the oil color shows that there is water in it and that the coolant level had dropped. The leak according to him is through engine and not directly under it.

He said that this has happened because of head gasket failure when the engine overheated. This agrees well with comments you all have given.

So now, he is quoting $3800 to do the repairs which includes water pump replacement - with one year of parts and labor warranty. Would this make sense to do? I am OK to pay that if I know that the car would be functional after the repair and there is not permanent damage to other parts of the engine. According to him, this is unlikely as he didn't feel that when he was test driving it.

Any suggestions?

Fixing the existing motor is kind of a crap shoot. Once water gets into the oil, you have no idea if there was any damage done to the crankshaft bearings. I'd look into buying a used engine and swapping that in for that much money.
 
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2019 Mazda CX-9 Signature, Machine Grey Metallic
This water pump issue is the exact reason why we traded in our perfectly running 2010 CX-9 GT. Our vehicle wasn't experiencing the water pump issue yet, but with 103K miles, we felt it was a matter of when it was going to happen and felt that we didn't want to go through the hassle and expense. We started to minimize use of the CX-9 to mitigate the probability of the water pump failure until we traded it in this weekend for a 2019 CX-9 Signature.

If you have the option of trading it in, cut your losses and do that. Replacing the water pump (which requires pulling the engine since it is inside the engine) doesn't guarantee that the vehicle's engine is unaffected and, I agree, is a crapshoot. Either replace with a used/rebuilt engine (which will still have the engine design defect of that water pump) or trade the vehicle in.
 

helbigtw

T-Rav
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PA
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08 CX-9 GT FWD
This water pump issue is the exact reason why we traded in our perfectly running 2010 CX-9 GT. Our vehicle wasn't experiencing the water pump issue yet, but with 103K miles, we felt it was a matter of when it was going to happen and felt that we didn't want to go through the hassle and expense. We started to minimize use of the CX-9 to mitigate the probability of the water pump failure until we traded it in this weekend for a 2019 CX-9 Signature.

If you have the option of trading it in, cut your losses and do that. Replacing the water pump (which requires pulling the engine since it is inside the engine) doesn't guarantee that the vehicle's engine is unaffected and, I agree, is a crapshoot. Either replace with a used/rebuilt engine (which will still have the engine design defect of that water pump) or trade the vehicle in.

Man, I am exactly where you were at. 103k miles on my 08' GT. Perfect vehicle all these years but the thought of the water pump going, and on top of that, all these brake booster failures I'm seeing here are giving me the heebeegeebees. Seriously eying the 2020 Toyota Highlander, still has a V6, and killer electronics & ergonomics. We also drive our CX-9 2 or 3,000 miles per year. Hate to get rid of it, but its time.
 
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Mazda CX-9 GS AWD
Thanks for all the responses to this post. I learned about the likely source of my problems here.
I just got my 2010 CX-9 back from my mechanic and it's fixed! Here's my story. With about 210K KM (130K miles) on it now.
The CEL went on about 6 months ago at 200K. I checked it with a scanner/app and learned it was the cam position sensor - fault code P0016, cam out of position. I had a few oil changes done in that time and no mention of water in oil. The engine ran fine, so I left it as I suspected it was just a sensor. Then a few weeks ago, I noticed an odd 'rattle' sound at idle from the top end/under valve cover. It went away when revved, but then I saw the coolant overflow tank was empty. There was water on the dipstick and a bit of 'milkshake' under the oil filler cap. I stopped driving it, and figured it was the waterpump and timing chain system problem. Dealers and other shops quoted between 12-17 hours to do the water pump replacement, dropping the motor. Likely about $3k worth of work. Others said don't bother fixing it as you never know what else has been damaged.

I took it to a retired mechanic friend to do the work in his home garage (with all the tools from his business). He researched the waterpump fix and determined he could do it without dropping the motor. Overall he said it wasn't too bad, but had the luxury of time to do it at his leisure over a week. Probably about 10-12 hours of work at a methodical pace, with lot of cleaning. There was fair amount of sludge, but not much water evidence. It was the pump leaking, and the timing chain tensioners were at the end of their adjustment range, which likely triggered the sensor. Luckily I caught it early enough.

He replaced the pump, long timing chain, two camshaft transfer chains, chain guides & tensioners, gaskets, spark plugs and miscellaneous bits. Parts cost was about $1000, plus his discounted labour. He did two oil changes after the fix to flush out any goop leftover. He didn't do a flush with solvents or anything, as he said that can cause other problems with hydraulic acutators etc.

The car sounds great now, and I'm happy to have it running. I'll keep it through the winter, and then trade-in next spring. I still think its risky to keep much longer. The list of problems is getting longer: The transmission torque converter is weak, the AWD light is on again (hopefully just the wire to the rear diff solenoid), the transfer case is time bomb. We replaced the windshield recently and found the source of leak, and wet drivers side carpet - rusted windshield frame. That rust isn't going away.

Overall, most of the problems with this generation of CX-9 are related to the FoMoCo supplied engine and drivetrain. If yours is running well, and can get a decent trade-in, get rid of it now.
 
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2019 Mazda CX-9 Signature, Machine Grey Metallic
Overall, most of the problems with this generation of CX-9 are related to the FoMoCo supplied engine and drivetrain. If yours is running well, and can get a decent trade-in, get rid of it now.

Glad you got it fixed. I agree with your statement that the Ford DNA of the previous gen CX-9 is what's causing all its issues. I traded in our 2010 CX-9 GT FWD late September and got $5400 for it. I just didn't want to deal with the hassle of replacing the water pump and thought to just trade it in while it ran well. We don't regret getting the 2019 CX-9 Signature that we traded it in for. Drove about 150 miles roundtrip yesterday and got 26mpg in mixed driving. I would have been lucky if I got 20mpg on the previous gen. While we liked our 2010 CX-9, we don't really miss it much.
 
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2010 CX-9 GT
Overall, most of the problems with this generation of CX-9 are related to the FoMoCo supplied engine and drivetrain. If yours is running well, and can get a decent trade-in, get rid of it now.

Aside from the terrible brake rotors, disposable power window motors, HVAC drain that repeatedly clogs and destroys a $450 blower motor, rusting control arms, bad airbags, questionable wheel bearings, rear power liftgate that destroys itself, and all the other minor but annoying crap that has gone wrong with mine, I agree, it's all Ford's fault.

Seriously, though, it's hard to figure out what the failure rate is on these engines due to the water pumps. Is it 1% of all engines or 0.1%, or 0.01%? I have no idea. It is not hard to find forum posts on the Edge, MKZ, and other forums talking about this issue, but Ford and Mazda put this engine in a lot of vehicles.
 
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