Coolant Pump on Hybrid May Fail and Cause CEL/Engine Shutdown on Mercury Mariner Hybrid

The hybrid models have a coolant pump that cools control electronics. The pump can fail or spin slowly, which causes a Check Engine Light to illuminate and complete engine shut down.

RepairPal Verified
Average mileage: 97,015 (36,700–185,000)
5 model years affected: 2006, 2007, 2008, 2009, more2010
50 people reported this problem
Get Your Car Fixed at a RepairPal Certified Shop.
We certify shops based on expertise, quality work, and verified customer reviews
Viewing 1 - 20 of 27 problem details
Having the same problem. What I don't understand is why is it not giving me a wrench to tell me something is wrong. In fact, it is saying the opposite, that everything is working fine and as it should. I had cruise control on, it happened about 50 miles from home. Just surged a bit, then completely shut down and gave me the PULL OVER SAFELY NOW message. Each time it happened I stopped and shut it off and restarted it and it never gave me any indication there was a problem until I got back on the highway and it happened again. and again. I had it towed to a dealer where it is now.
2007 Mercury Mariner Hybrid 78,000 mi,
car completely shuts down while driving...have to pull over and restart...will go for awhile and then have to keep doing this...we thought we had bought bad gas
2008 Mercury Mariner Hybrid 90,444 mi,
Coolant pump went out. Same issue with sudden shutdown and needing to pull over for a while. Repair was $560 including a new bracket. The only problem I have ever had with 90k miles. I read this website before going to dealer, told them it was likely the coolant pump, and their diagnosis was exactly the same. Thanks!
2009 Mercury Mariner Hybrid 96,000 mi,
this is the second time in less than a year . shuts engine down not safe on highways should have been a recall they all do it .what makes this coolant pump fail
2006 Mercury Mariner Hybrid 103,000 mi,
Same as previous, Shut down on interstate with limited exits available. Very scary as we were a long way from home. Recall should take place, very dangerous if in the wrong place when it shuts down. We had just purchased the vehicle, so we had anther car following, A 2 hour rip took 9hrs and ended up driving home in the Prius to get truck and trailer to retrieve it on , arriving at 11:15 pm. This msgboard has been a big help, will also follow up with Ford
2008 Mercury Mariner Hybrid 108,000 mi,
Was driving on freeway, engine shut off with alert to "Pull Over Safely Now". Was able to restart the vehicle, but it shut off again. Had it towed to a Ford dealership and confirmed it was the hybrid mechanical pump for cooling the hybrid system.
2007 Mercury Mariner Hybrid 92,000 mi,
This same problem happened to my 2007 hybrid. Check engine light came on and engine quit. After pulling over the car was able to restart. We did this on backroads continually for our 80 mile drive home, the car ran a little less time after each restart. The coolant pump was replaced - I'm thinking it was in the $400 range.
2008 Mercury Mariner Hybrid 75,900 mi,
Thanks to all of you sharing your experiences. I too was having my vehicle shut off while driving. Would pull over and wait a couple of minutes and back on the road I was. Two minutes later it shuts off and tells me to pull over safely. No wrench or anything telling what the problem is. I too had it towed but to my house. The next day the wife used with no problems for the next two days. I then drove it and off it goes again. Made it home and left it alone. Got on this web site and read that the same problem occurred with my car. I bought the Coolant pump myself and replaced it ($182.00). Problem solved...for now.
2007 Mercury Mariner Hybrid 107,500 mi,
My mercury mariner hybrid stalls on the interstate. Just prior to the stall, the vehicle seems to lunge forward slightly, then the engine quits. We have to pull over and restart. One day this happened to me twice, within a few hours apart of each other.
2007 Mercury Mariner Hybrid 90,000 mi,
Engine shutdown suddenly on interstate at 70 mph. VERY dangerous and scary. Dealer replaced fan, but I was on vacation and the wait for parts and service used up time I had planned for other things. Other than this problem, vehicle has been reliable.
2006 Mercury Mariner Hybrid 109,000 mi,
Hey guys, I'm not sure if this has been posted yet but to anyone else who is having this problem... ** A recall HAS been announced for this ** Ford will pay for the repair free of charge, it is recall # 14S19. I'll link to the page detailing the information. Thank God.
2006 Mercury Mariner Hybrid 78,000 mi,
Complete shutdown on freeway with "pull over safely warning". Had to leave car 4.5 hours from home and complete trip in rental car. Will have to drive back and forth for a total of 9 hours to get truck back home...
2007 Mercury Mariner Hybrid 62,000 mi,
I had a problem with my coolant pump. Car was undrivable and part had to be replaced.
2006 Mercury Mariner Hybrid 129,000 mi,
Identical problem. In our case, just two weeks after purchasing the car, which passed a mechanic's check with flying colors. Dealer charged about $400 in parts and labor. Dealer says these cars (including Escape Hybrid) have been so trouble-free that this is their top problem. I had seen notice of a possible class-action suit. Delighted to see Ford's announcement of recall today, referring to a new, brushless pump -- ideally a real solution!
Between 65 -70 mph the engine cuts off and a message pops upsaying pull over safely. I cannot believe they haven't issued a recall on this yet
2008 Mercury Mariner Hybrid 91,000 mi,
going 70 on the highway...truck surged...then engine cut out. told to safely pull over. no warning, no wrench. this should be a safety recall!!!!
They replaced the coolant pump. Then 300 miles later same problem!
2006 Mercury Mariner Hybrid 120,000 mi,
Came to a stop light and when I went to step on the gas the car was completely shut off, and didn't move, and the Safely Pull Over indicator came on. I couldn't pull off the road because I was at a stop, but a guy came along and pushed me over to the side of the road. I turned the car off, then back on and nothing happened. I shut it off, waited a minute, then turned it on again, and it started, and I drove home. Taking the car in for a diagnostic. The guy that pushed my car said it had a burning smell. I couldn't smell it sitting in the car. I am sure it is the Coolant Pump, but will have it checked out. THERE SHOULD BE A RECALL ON THIS PROBLEM BEFORE ANYONE GETS KILLED ON THE ROAD!!!!!!!!!!!!!!!
2007 Mercury Mariner Hybrid 68,000 mi,
My engine shut down when I was driving and I lost the ability to steer or brake. The mechanics couldn't get the problem to happen again so they reset the computer and said it was probably ok to drive.
2008 Mercury Mariner Hybrid 114,799 mi,
shortly after purchasing used 2008 mariner it shut off on the frwy, "triangle w/!" went on but nothing else except "pull over safely now!" did so, turned car off then on & conteniued on my trip. months later it happened again then just last week it turned off several times during a very short trip. a day or two later with this pattern continued finally the "temperature indicator" lit & said "motor temp high!" took it to aamco had "motor electronic cooling system pump" replaced for $573.25! I will soon find out if its been fixed!