2009 Lincoln MKX - New engine!?

was told there was water in oil due to a coolant leak. Said we need a new engine.

That’s certainly possible. The more water, and the longer the water was in the oil, the more likely the engine will need major repairs or replacement. I presume the cause speculated by the shop is a head gasket leak? What does the shop cite as evidence for that finding? There are other reasons why there might be small amounts of water in the oil., for example if the engine was idled frequently, or it was mostly short trips, so it seldom reached normal operating temperature.

No, a water pump leak.

It sounds like this water pump is driven by the timing chain . . . ?

Entirely possible. If the water pump (which is inside the engine) develops a leak, it can mix coolant into the oil.

If you drive it this way long enough, it can damage the engine.

How low was the coolant and how long was it being driven that way?

Even if the water pump leak is quite recent and small, many shops would be hesitant to do a partial repair on a 15 year old engine.


What an incredibly stupid design! And this is not unique to the OP’s vehicle. Apparently, there are several Ford engines with this defective design, including, but not limited to the Ford Flex…hence why you rarely see a Ford Flex on the road today. To put this into perspective, the Ford Flex, and Honda Element used to be on the road here in roughly equal numbers. Now, I can’t remember the last time I saw a Ford Flex in public, but I see a Honda Element at least several times per week.

Personally, I would NEVER buy any vehicle with an engine containing an internal water pump, driven by a timing chain. This design makes it impossible to notice that the bearings are going bad, the shaft seal is leaking, or the gasket is leaking, until it is too late.

Many brands of cars use this design. Water pumps perform better and last longer when they are internal to the engine and run by the timing chain. They tend to be smaller and lighter, and allow for better packaging in the engine bay. These are all good things, right?

Funny you mention that car. I see one every day. My 2006 Trailblazer was getting long in the tooth, so last year I sold it and picked up a Ford Flex.

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Water pumps pretty much always leak eventually. It’s a shame if this minor problem would cause major damage to the engine. I wonder if there’s technology available that would tell the owner there’s coolant intrusion into the engine oil? If that’s not possible, maybe there’s something that would at least inform the owner the water pump is leaking. Does coolant from a leaking water pump w/this design always wind up in the oil sump? Or does there have to be another failure somewhere?

Sure does. Even when there’s technically a “drip tube” to allow it to exit externally. A good example is the Chrysler 2.7L V-6. Great on paper, but in reality, the timing chain-driven water pump led to coolant leaks into the crankcase, and jumped timing on this interference engine. Needless to say, very few of these are left, which still run.

Not necessarily, I have seen coolant leak from the weep oil on the 2.7 liter engine, that would be the time to replace the water pump.