CX-9 Timing Chain, Water Pump, and VVT - Engine does not need to be removed

dougtex28 said:

Accessing the timing chain, water pump, and VVT actuators require removal of the timing chain cover which there seems to be some debate on if the engine needs to be removed to accomplish this. The Mazda service manual says to remove it, but I think that is just because it is a tight fit and there is not a lot of room to work with. Most people would not want to remove the engine just to replace one of these components and luckily we do not have to. I just completed replacement of all of these parts in my 2011 Mazda CX-9 and the engine did not need to be removed. I did have to raise and lower the engine as needed to access bolts and remove the timing chain cover, but that is not unusual when replacing a timing chain on most front-wheel drive vehicles. I'm working on the DIY for this, which may take me a week or two, but wanted to start up the thread for this.

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dougtex28 said:

To explain on why/when replacement may be necessary, here is my 2 cents:

If the water pump fails, you'll know it. Coolant will get into your crankcase and turn the oil into mud. This is bad, really bad. From the other threads, it seems cost to have this work done is around $2K (plus or minus). If you have to replace the water pump, you may want to replace the primary chain while you are in there. It is only $30-$40 for OEM replacement and although chains do not typically break the way timing belts do, they can stretch over time. Besides, the primary chain has to come off to remove the water pump anyways.

Timing chain issues on this engine seem to be related to it becoming noisy. It is even possible for it jump in extreme circumstances, such as a collision. If it jumps, you may get a P0016 code for crankshaft and camshaft position correlation (P0016 being for bank 1 - the right side of the engine which is closest to the firewall). A noise condition could be due to the chain stretching or the tensioner failing. So if you are in there for any reason (such as water pump replacement), I would say replace the tensioner along with the primary chain, it is a small investment that may save you pain down the road.

VVT Actuators can potentially fail and they may give you the same type of code as a chain that skips, like a P0016 code. Very difficult to diagnose and this is what brought me to opening up my engine. These are a bit pricey (around $100-$150 each and you need one for the right and one for the left). I had the P0016 code which I think was due to the chain, but have read about these failing so I went ahead and replaced both of them. A bigger price investment, but I did not want to have to go back in.

The parts can really start to add up, so you may need to make some decisions on what you want to replace while you are in there. I went the expensive route and just replaced everything within reasonl, including chain guides, valve cover gaskets, and spark plugs.

I'll do a more intensive DIY, but the basics are as follows:
Disconnect battery
Drain Oil (and leave the plug out)
Drain coolant
Remove airbox
Remove intake manifold
Remove valve covers
Remove belts (AC and Power Steering)
Remove power steering pump
Remove engine mount on the passenger frame (be sure to support engine)
Remove crankshaft pulley
Remove bracket that was attached to the engine mount
Remove Serpentine Belt Tensioner
Remove timing cover

That will get you access to all the items of interest (timing chain, water pump, VVT actuators)

From there, you need to be really careful with aligning the crankshaft and camshafts to the proper position, marking the timing chain, locking down the camshafts if you are replacing VVTs, and of course realignment of everything for when the chain goes back on. There will be a big gush of coolant that comes out when you pull the water pump, so be ready for it and use plastic to block of the oil pan from that rush of coolant. Even after draining the coolant from the radiator drain plug there is a lot still sitting in the engine. When I re-filled coolant after the repair it took a little over two gallons to top it off.

I'll include a list of parts and tools used in the DIY, but it wasn't anything too crazy. It can be done without air tools, although air tools always make it a bit easier. I only used my air tools to remove the crankshaft bolt, but there are ways of doing it without it.

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Pootie Tang said:

After spending HOURS trying to figure out WHERE this water pump is, using Google search, forums, and finally Wikipedia on the CX-9 and the Duratec 37 engine (35 for 2007 models) which I think goes through 2010, the pump is located on the passenger side of the engine (not the driver's side), in between the timing chains. If you are looking at the engine with the hood up from the front bumper, it will be on your left, behind the accessory belt. It is part of the timing chain loop.

Here is a great video of a mechanic having to replace the water pump on a 2010 Ford Flex which uses the same Duratec 37. It is a very involved job. https://www.youtube.com/watch?v=VjMgagyP0SI

Also, I wouldn't touch the headgaskets. Headgaskets are not a regular service item and usually never need to be changed unless the engine overheats severely.

Use Mazda factory coolant and distilled water for the cooling system to minimize your risk of pump failure.

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dougtex28 said:

I didn't go as far as head gaskets, not sure if they have much risk for failure. If you have 168k, you definitely want to replace any of the moving parts in the timing chain section. I only replaced the primary chain as it is the highest risk for stretching due to being much longer than the camshaft chains. I didn't mention the details beyond getting the timing cover off as it is really simple once you get to that point, although I can show it in the DIY. The water pump is easy once exposed, the real trick is getting all three timing chains aligned. I took all of them off because I replaced the VVT actuators while I was in there.

Here is a pic of the actual water pump, it is in the center of the timing chain path and it is driven by the timing chain:
View attachment 215244

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Pootie Tang said:

After spending HOURS trying to figure out WHERE this water pump is, using Google search, forums, and finally Wikipedia on the CX-9 and the Duratec 37 engine (35 for 2007 models) which I think goes through 2010, the pump is located on the passenger side of the engine (not the driver's side), in between the timing chains. If you are looking at the engine with the hood up from the front bumper, it will be on your left, behind the accessory belt. It is part of the timing chain loop.

Here is a great video of a mechanic having to replace the water pump on a 2010 Ford Flex which uses the same Duratec 37. It is a very involved job. https://www.youtube.com/watch?v=VjMgagyP0SI

Also, I wouldn't touch the headgaskets. Headgaskets are not a regular service item and usually never need to be changed unless the engine overheats severely.

Use Mazda factory coolant and distilled water for the cooling system to minimize your risk of pump failure.

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dougtex28 said:

I didn't go as far as head gaskets, not sure if they have much risk for failure. If you have 168k, you definitely want to replace any of the moving parts in the timing chain section. I only replaced the primary chain as it is the highest risk for stretching due to being much longer than the camshaft chains. I didn't mention the details beyond getting the timing cover off as it is really simple once you get to that point, although I can show it in the DIY. The water pump is easy once exposed, the real trick is getting all three timing chains aligned. I took all of them off because I replaced the VVT actuators while I was in there.

Here is a pic of the actual water pump, it is in the center of the timing chain path and it is driven by the timing chain:
View attachment 215244

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GJ-Molestor said:

Thanks very much for this post, this is helpful for anyone who got the v6 engine. I have absolutely no idea why Mazdas engineers placed the water pump where they did, but oh well...

Timing chains are supposed to be good for the life of the engine, but it is more likely to become stretched if you do not change the oil regularly.

Im not sure if th VVT mechanism is oil-pressure related (it likely is) but again, very important to keep your oil nice and clean.

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Thaumaturge said:

I hesitate posting to this old resurrected thread, but the above statements require a response.

While the location of the water pump is a pain for everyone concerned, it is becoming a very common location in transverse-mounted engines with tiny engine bays. The ease of installing the engine during manufacture was clearly more important than ease of service. (the same goes for the right bank of spark plugs)

Regular oil changes have almost zero effect on timing chain elongation/failure - heat does. Yes, bad lube increases friction, but the chain has very small contact points unlike pistons, etc..

If the engine overheats for any reason, the timing chain metal can be damaged on a molecular level just like any other metal part. All metals stretch and timing chains are no exception. If the timing chain alloy was too inelastic it would damage other components so in many respects it is the weakest link (pun intended) by design. That having been said, timing chains do wear out and elongate due to the link pins wearing over many many miles but this unlikely event is the least of your worries in this engine.

The VVT in this engine is dependent on oil pressure. The solenoids activate little 'valves' that are protected by screens and allow the VVT to change the timing when required. Dirty oil can foul these screens and stop the VVT from operating correctly. Note that a faulty VVT will not stop the engine from running but will affect mileage and power response.


For more information and pics of the water pump, timing chain, and VVT go here:
https://www.mazdas247.com/forum/showthread.php?123863307-CX-9-Water-Pump-Replacement-DIY-Guide

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GJ-Molestor said:

thank you for the response, very helpful.

I mentioned the timing chain issue because it's a very common issue with the 2012+ BMW 28i models equipped with the turbocharged 4 cylinder. apparently people were experiencing timing chain failures attributed to BMW's very lengthy oil change intervals, but I suspect this is the case because BMW purposely uses plastic timing chain guides in their 4 cylinder and V8 models which constantly fail.

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Thaumaturge said:

FYI, Just about every manufacturer uses a plastic material on the chain guides including Mazda. The plastic is the wear layer. Metal would be far noisier and would risk metal filings from chain and guide wear.

As an aside, the failures on E38/E39 BMW engines (I used to own a E38, 7-series = expensive junk) were due to the plastic layer coming loose from the metal substructure on the old engines. The newer BMW parts are sometimes all plastic which boggles my mind even more. They solved the "coming" loose problem by eliminating the metal entirely! Similar designs have been used by Jaguar, VW and others with similar bad results. In a lot of these cases, the tensioners failed first and stressed the plastics into failure.

I am happy that only the wear layer is involved in the CX-9 V6 guides and I have yet to hear of anyone with a failed timing chain guide in our engines.

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dougtex28 said:

...Most people would not want to remove the engine just to replace one of these components and luckily we do not have to. I just completed replacement of all of these parts in my 2011 Mazda CX-9 and the engine did not need to be removed...

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