Hi,

In the Spring I will do the waterpump on our 2009 Ford Flex with the normally aspirated 3.5L V6. This will be a pro-active replacement, the waterpumps in this engine have shown enough evidence of failure that leads to coolant contamination of the oil, if it doesn't show leakage from weep holes located on intake manifold valley or behind alternator at bumper side of engine.

Presently the Flex is a 200,000 km (125,000 miles) and shows no leaks and runs fine. I've been running PP 5W20 or 5W30 for the last 100,000 km and this car has always been well maintained.

My question:

I plan to replace the following parts with this project, item and source:

- Waterpump - Motorcraft
- Main Timing Chain - Motorcraft
- Main Chain Guides 3pc - Motorcraft
- Crank Sprocket - Motorcraft
- Main Chain Tensioner - Motorcraft
- Crank Seal - Whatever brand RA is carrying??
- Full Valve Cover Gasket Set - Felpro?
- Intake manifold gasket set - Felpro?
- Stretch Belt for PS - Continental
- Main serpentine drive belt for accessories - Continental
- Harmonic Balancer Bolt (TTY type) - Motorcraft
- Oil & Filter, PP 5W30 and Motorcraft FL500S
- Ford sealant 357 ?? for the front cover to engine
- Ford Specialty Green Coolant
- distilled water for mixing with new coolant
- Partial flush of PS fluid - this has been partially flushed with turkey baster before.

I do not plan to replace:
- 2 smaller Camshaft Chains
- 2 Cam Tensioners
- Cam sprockets

Reason for not feeling need to replace above cam chain related item: The engine will have about 207,000 km when I do this work, the reason is to have some peace of mind about a ticking time bomb of a WP, there is no real issue with the timing chains stretching on this engine, and with use of good quality oils, I should be able to skip the replacement of the cam chains. Am I an idiot?

The plan is that we will have the car for maybe 5 more years, the body is good. The end of plan would have the car at 310,000km if the current use pattern is played forward, all future maintenance will be to the same high level as the first 10 years.

The scope of this work is going to be big for me, but I've done this kind of thing before with good results. I started getting the special tools for last Christmas

Do you agree with my concept of leaving the cam chains out of the project?

And they say bitogers have too much time on their hands....IIRC the tensioner for the chain you’re thinking of replacing extends out to take up any slack the chain may have gained. A quick inspection of it will tell you if your chains are shot or not. If it’s hardly extended you might to chance it. But then again a new chain isn’t that much more....project creep city!

125k miles and you're changing all that for no reason? lol

your choice for sure + prolly not a bad idea, but if the Stealer was doing it you could prolly buy another car! many engines today go very long miles, + my 200,000 mile 2001 jetta 1.8T ran great at trade time with 20" on the vac-boost gauge i installed. i put 2 complete timing belt kits on it costing about $700 in parts for both times. most chains are better but they stretch as well + can cause issues as the tensioners only have so much take up.

I need to ask what does the oil used in the engine have to do with the water pump?

Does it make any rattling noises at startup? I understand the WP replacement, but I’m not sure I would do the chain unless something is wrong with it. My MGM could use one, but I would have to buy the special cam locator tools & crankshaft holder tool to do it-& I’ve heard a lot of 4.6s sound a lot worse than mine!

Does not sound unreasonable at all to all the work you are doing.

Pretty sure there is still class action lawsuits going on because of the water pump destroying engines.

Chain is sitting right there staring you in the face doing the pump.

It might seem like that, but the net is now showing that many of the Ford 3.5V6 engines are failing due to the internal Waterpump leaking coolant to the oil. The Mazda CX9 is also affected - same engine for some years.

The failure mode is usually while driving on the highway. The Waterpump is driven by the main timing chain and is not accessible for replacement without removal of the main timing chain system. Pretty labour intensive process to get in there and change the WP.

Some people would say, leave it until it starts to fail, but I prefer to do my wrenching when the weather is nice, and my schedule supports taking the time needed to do the work carefully. I've done head gasket work in February in an unheated garage and that SUCKS.

It doesn't. However, if the all the chains are stretched due to abuse of proper oil maintenance, then the smart person would replace ALL chains and ALL tensioners.

The WP is going to be replaced, I can save myself some time and about $200 if I don't bother replacing the 2 cam chains, 2 cam tensioners, 2 cam sprockets - the reasoning being that if these items show little stretch, they should be fine for at least another 150,000km.

I guess I could just do the WP and keep all the existing timing parts original, but that's squeezing the buffalo a bit too hard for me

As an owner of a Ford 3.5 with this waterpump design that has 129k I'm not planning on any changes to the pump. We all have no idea what the failure rate of these pumps is vs the millions of transverse 3.5's in the wild. Remember it was used on volume Ford, Lincoln, Mercury, and some Mazda vehicles since 2007. So literally millions and millions of them on the road. Say there are 1 million on the road - 1% failure rate is 10,000 engines. Enough to trip the Internet meter but not enough to worry about it.

You replace it, there is no guarantees that the new pump doesn't have some odd defect and wipes out the engine. Then you're back with what you are trying to avoid.

IMHO best to run it for the extra 103,000 km (64,001 miles) on the existing waterpump and keep a watchful eye on it. While the 6f50 is a great trans I'd be more concerned about it or the PTU as they near 200k.

Also do the spark plugs. NGK Laser Iridium or Denso Iridium TT. The new rutheniums from NGK don't seem to be offered for your Flex yet, otherwise that would be my top pick. Transverse V6's are impossible to do plugs on, so you want something that will last a long long time so you don't have to go back there again.

If you can still get the Continental Elite cogged belts, get them! Otherwise, Bando.

Timing chains don't normally need to be replaced unless they are known to be problematic on specific engines (such as GM's Quad 4), or on some recent GDI/TGDI engines that have had problems with timing chains, or if your car never had an oil change. However, replacing the tensioner is still a good idea.

My parents have over 360,000kms kms on their 2010 Taurus same engine. No issues so far but I think they should do at least the water pump for peace of mind. I also know of one with 440k plus with no work done but its a 2012 I believe. Lots of highway miles. I don't think the failure rate is high but it wouldn't hurt to do it at 200k if you definitely need it to last over 300k.

I feel the same way about my 370,000km (230k) timing chain in my Caprice even though many have put 400-600k or more without a timing chain apparently. I'd feel better if it was replaced.

*The position of the exhaust cams is not monitored by the ECM, So you don't have to worry about dreaded Cam/Crank correlation codes due to the secondary timing chains.
*I'm guessing you don't have Cam/Crank correlation codes due to main timing chain stretch/wear?
*The main timing chain is MUCH more likely to stretch than the secondary timing chains due to it's MUCH greater length.

No correlation codes........I wouldn't mess with the secondary chains!! But would definitely replace the main TC, guides, & tensioner while doing a water pump.

An '83 Caprice (Chevy 305) would have a Nylon Clad Aluminum camshaft gear from the factory, I have never seen one make it to 200,000 miles.....Most would be heavily worn by 80,000 miles. I almost guarantee your car has had a timing set installed at some point in it's life! Not something you could make better by over maintaining either.
The HD set used in the trucks on the other hand could go forever....Usually EOL of the engine.

Well we will find out when I take it apart I guess. It could have been done years before I bought it (the previous owner didn't) at 165k miles.

Garak on this site has experience with a fleet of cabs, lot of them with this engine and he doesn't recall having any timing chain issues.

Lots of them went over 200k. Most that did fail wore through the timing cover before jumping.

One of my previous Caprices was an 87 with the Olds 307. I replaced it's timing chain at 160k miles and it had some stretch but the original nylon gears were still intact with some minor stress cracking starting. I hear lots of people say they only went 80k but in my experience that hasn't been the case. My friend who was a ford mechanic back in the 80s said a lot of Ford's were wear out by that mileage but it doesn't seem to be the case for the Chevy or Olds engines.