Changing the water pump to be on the safe side

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08 cx9 grand touring
I have a 2008 cx9 (3.7) I'm wondering if it's worth it to be proactive and change the water pump and timing chain to be proactive. Everything seems to be working fine now but I'm reading horror stories about water pump failures and catastrophic engine failure after 100K miles

Is it worth it?
Major project that I won't be doing myself and I'm guessing around $2000 at a shop
In the real world how often do they fail?
 
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The problem I'd have with proactively replacing the WP is the questionable quality/longevity of replacement parts. And buying an 'OEM' pump directly from Mazda is not likely to guarantee success here either, because who knows what 3rd party outfit has taken over making this part after so many years. It would be a total kick in the A$$ to have the engine croak in a year or so, due to a failed replacement pump (or some issue with the work that doesn't show up right away). And if something like that did happen after whatever warranty the shop gives, good luck trying to get any compensation from them.

If I owned one of these internal pump vehicles, I'd add UV dye to the coolant and examine the oil with UV glasses regularly for the presence of the dye. And as a cross-check, a sample of the oil can be sent to a lab for testing, when the oil is changed.

If coolant is immediately found to be present in the oil, then you might have a tough decision, because you wouldn't know how long coolant has been leaking, and how much damage has already been done. However, if no coolant is currently found in the oil, then you can relax and just keep monitoring going forward.
 
Is the 3.7 known for water pump or chain problems? If not, I wouldn't change them. JMO. ED
 
I have a 2008 cx9 (3.7) I'm wondering if it's worth it to be proactive and change the water pump and timing chain to be proactive. Everything seems to be working fine now but I'm reading horror stories about water pump failures and catastrophic engine failure after 100K miles

Is it worth it?
Major project that I won't be doing myself and I'm guessing around $2000 at a shop
In the real world how often do they fail?

Nobody but Ford and Mazda knows what the failure rate on these pumps are, and neither of them has shared it publicly. To be honest, the rate seems relatively low given the sporadic nature of the posts here and on the various Ford message boards. Looking around, there are engines with 200k+ miles still on their original water pumps, while some of the reports of failure here were with under 50k. This is one of those issues that seems relatively uncommon but can be a catastrophe should it occur.

Ford still makes a derivative of this engine with the same water pump design, and there are probably a million+ of these motors in use right now, so I wouldn't worry about the part quality or availability. The decision really comes down to how long you think you are going to keep the car and if it's worth it to you to spend $2k (or more, that estimate is from a few years ago) on a maintenance item, or if you should just save that money as part of the down payment on your next vehicle.

If you don't plan on doing it yourself, I'd probably lean towards leaving it alone. You can get in the habit of checking the coolant level in the overflow bottle in the morning when the engine is cold. I check mine once a week or so - it's filled to exactly the "L" mark on the coolant overflow when cold, and I park it in the same place all the time so it's pretty unambiguous. This will alert you to a slow leak, but doesn't protect you from a sudden failure.

Good luck.
 
I wouldn't. There is no guarantee that the replacement won't fail.

The best thing is to be aware of the problem, check the coolant on a regular basis, and watch the temperature gauge. If driving and the temp gauge is anywhere but normal, shut her down immediately and investigate.
 
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How many miles are on your CX9?
How much longer do you plan to keep it?

My wife's 09 CX9 was at 185k on original water pump and coolant when we sold it a few years ago.
I think I added a total of 1/2 qt coolant to the reservoir in the ~10 years we owned it, so it really didn't lose any considerable coolant. I kept an eye on the reservoir to make sure it didn't just drain one day.
 
I have a 2008 cx9 (3.7) I'm wondering if it's worth it to be proactive and change the water pump and timing chain to be proactive. Everything seems to be working fine now but I'm reading horror stories about water pump failures and catastrophic engine failure after 100K miles

Is it worth it?
Major project that I won't be doing myself and I'm guessing around $2000 at a shop
In the real world how often do they fail?
did you ever change the water pump?
 
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