Hey all, VERY long time lurker, first time poster.

I have a problem with my 09 MMH, less than 60k miles on it, just got it 6 months ago. I'll try to describe the problem as best I can but I may not have the right words as I can't find similar problems after weeks of googling... 3 problems that seem to be related...

1. Only under certain conditions, the transmission seems to "slip" at a "shift point" and the vehicle loses power. (I know this is a CVT and these are made up terms, just trying to describe). It has almost always been right about 40 mph and under a light/moderate but consistent throttle. When this is going to happen, I can feel it and feel like can cause it. But most times, this doesn't happen. Seems to happen more in cold.

2. On a morning after the car has sat (eg, for an entire day or weekend), the idle starts normal then can shoot up to 3k RPMs. This isn't right, but it isn't horrible. Mostly it seems to indicate problem #1 will occur on this outing.

3. Occasionally, on light, consistent deceleration from about 45 mph, the car will seem to jerk a bit. Almost like problem #1 in reverse. It is very dramatic when it happens. I described this once as almost a antilock brakes problem, but smaller.

My efforts to diagnose/fix have been spotty. I've found very little online that is similar, however I once found a post here that someone described a problem similar, but was told they may not be used to how a hybrid works. If I could go find that post again, I would tell them I agreed with them. I found out that Ford had extended the warranty on throttle bodies for this year, so I replaced that. However, the throttle body looked like it had already been replaced (evidenced by the manufacturing date stamp being 4/17 on that little stamp dial). So I took the unused part back.

HOWEVER when I pulled the throttle body off, I put a flashlight down into the manifold and saw brown milky liquid. Is this normal?? It had a feel of antifreeze, but smelled of gas (obviously everything in there does), and was brown. Do I have a blown gasket?

Please help me diagnose this, as it is my wife's and she is pissed! I know this isn't just a "hybrid newbie" issue, as we have driven an 08 MMH for 6 years, and I also have driven a Prius for 2. We know hybrids.

Thanks for any and all help!

 

1. when cold and cold outside (hybrid battery less than 50°F), assist/regen can be disabled. In the case of assist, the engine revs higher for power.
2. see #1
3. EGR issue?

Brown slippery fluid is certainly a concern. Is your coolant level consistent? If you have coolant seeping into the intake, I believe it could explain all three.

 

Thanks for replying! I don't think this is a disablement of assist/regen, as my experience with my '08 has never given me pause like this does, and I've had that in temps -10 F before... though I'm sure the '09 could be different.

The coolant level is on the bottom side of the fill level, so until now it hadn't been a concern. When I had the throttle body off the other night, the pool of liquid was deep enough to cover the head of my telescoping light, so it was significant. I soaked all that up (confident I got it all) and put another 70-80ish miles on and checked again with the throttle body removed, and some was back, though not as deep at all. Maybe 2 50 cent pieces in volume. If that is seeping in, does that indicate a head gasket? Intake gasket? Would a compression test confirm it?

 

Ford had a very bad run of Throttle Body issues around that time. If your Mariner does not have the "updated" Throttle Body i would swap that out. Some people unknowingly were demanding OEM with the coolant lines these are NOT the updated design and will fail quickly
It is easy to identify the original design which used a coolant line hooked directly to the throttle body itself and circulated coolant through it.

 

Thanks, I do have the latest throttle body as mine looks nothing like your picture, and was manufactured (FoMoCo) in 2017, so I think I'm good there!

 

OK.. Go ahead and Pressure test the cooling system..

 

So, in case anyone was interested, it took until today to get a (final?) answer. The dealership says that it is the hybrid motor, not the transmission. This seems odd to me because I can go whole days with this operating just fine... but I guess I can't complain. Because I got it only 5 months ago, the dealer I got it from (not the same one) is offering a buyback but will not replace the motor as Ford quoted $10,000 for the work, which is as much or more than the vehicle is worth. I haven't yet floated the idea of getting a used or parted hybrid motor from somewhere, but I doubt I should do that anyways.... the one thing I would like to do (as they will probably just auction this off after a buyback) is take the hybrid battery out... it has about 130,000 fewer miles than our other MMH...

Anyone ever talk a dealer into letting them do that?

Thanks for the help all!

 

How did your situation eventually pan out?

 

Thanks for asking. TLDR: It ended up being a problem with the hybrid motor according to Ford. I have no idea how they diagnosed that and I fought them for more details, but it had taken a couple months as it was so I let the details go...

The long story is that I got better and better at reproducing the problem. So much so that I took it to the dealership and demanded that a tech go for a ride with me so I could make sure they were feeling/hearing the same thing. We went for a few miles and I was getting nervous as it wasn't seeming to happen. But then as I decelerated to the turn around point and head back, it kicked in more noticeable than ever. The tech was pretty laid back but even he was taken aback and muttered "that's not good". He guessed that it was the transmission and told his manager they needed to get verification. This was at Carmax and so they were the ones to send it to a Ford dealer.

The good thing about this situation, and I have to share this, is that the dealer bought the car back from me, even though it was purchased 6 months ago without any extended warranty at all. We got this MMH from CarMax and I cannot say enough good about their service to us. Let me repeat we did not buy the carmax warranty and they still bought the car back from us, well beyond the 6 month timeframe. Really good people they are. I would wholeheartedly recommend shopping there and I will do so for every car I purchase in the future. They definitely don't have the best prices, but they have reasonable prices if you are like me and ok with getting a good value with little effort rather than spending hours on the search and negotiation.

I have to say it again: They bought the car back to me at full purchase price, plus refunded interest paid from the loan. Literally the only money I was out was the state taxes, as I owned the car as of Jan 1 and in my state that is who pays the tax.

Thanks for asking, if anyone has any other questions feel free to hit me up.