Sudden coolant leak from rear of engine

[762mm]

I hate my luck! I just came home from work (using my other car) and noticed a puddle under the engine of the Expedition that wasn't there a few days ago. I parked it there after a long drive yesterday evening. I went under the truck and could see droplets of coolant all over the cross members and rear sway bar at the front wheels. Is there any common / known rear coolant leak issue with these 3 valve Tritons?

I don't have time to put the truck up on ramps for a complete inspection until at least the weekend... I looked under the hood with a flashlight and can't see any leaks from the top of the engine.



Pictures of what I was able to see so far. You can see orange droplets and wet areas all over the place. It definitely smells and feels like coolant :

 

[762mm]

Extra info : I noticed the coolant being a bit low when I bought the truck and had to fill it with about 1 quart of distilled water (temporary solution until I flush / change it completely before winter). I figured it must've evaporated over time and use. I took a peek into the reservoir and it's low again... radiator is a bit low too.

The other thing I noticed is that I can hear bubbling coming from the heater core whenever I start the truck cold and also can sometimes hear water rush when I give it some gas, as if the thermostat was stuck open. I checked and it's not bubbling in the reservoir or under the radiator cap with the engine on, however (knock on wood!)

 

[Hans Schroeder]

I have 2 guesses, both have happened to me, though both on my old 1998 Expedition (5.4). The newer 2010 has had no coolant issues. First was a leak / crack at the heater core to hose interface at the firewall. That required removal of the entire dash (would as well with the 2010). The other issue was a blown head gasket - rear passenger side of the engine. The other thing I can think of that could happen is a freeze plug partially coming out on the back of the engine (noticed you are from Canada and likely face very cold winter temps). Sorry, none of those are easy fixes.

 

[762mm]

Thanks for the info. I read a bit about the other issues and am hoping it's not a head gasket. I don't really know what the freeze plug is, but someone on another (F150) forum mentioned the transmission needs to come out for that... ?

I will try to take a look at it as soon as I can. Some people have had quick disconnect hoses go bad under the water pump and then the fans blow the coolant towards the back on their F150's. Keeping my fingers crossed for an easy fix!

https://www.f150forum.com/f38/coolant-leak-rear-engine-393517/

 

[Adieu]

Heater hoses, 2 of em, one like a Y one like a T, passenger side past the cylinders and into the firewall

They're your likely suspects

Also, watch for coolant pooling in plug wells #2 and #3, that often happens and then two coils go bad you get rotted plugs and misfires

 

[Flight-ER-Doc]

My '15 Ecoboost is at the shop right now for a similar problem...waiting to hear what the issue is

 

[Flight-ER-Doc]

Just got the word from the shop, my issue was a leaking WP (85k miles)....

Well, not that big a deal, I guess.

 

[762mm]

FOUND IT !


I managed to find time to put it up on ramps today after work and take a closer look. I followed the coolant trail from the back to the front and it ended at the front of the oil pan. I then proceeded vertical and noticed this:













My guess is either the seal on the water pump gone bad or the weep hole ******* everywhere. I have a new Motorcraft water pump that I was going to install before winter anyway, so this is really not much of a problem (best case scenario in my case, I guess).

Now the concerning part : despite having the truck on for only a minute, the coolant was POURING out of this stupid thing when engine was running! I don't even want to think what would happen if the pump seal or weep hole failed like that on the freeway on a long trip. The only way you'd find out is when the engine stalled from having overheated, I guess.... because engine temp is measured in the coolant, it probably wouldn't even alert you to the problem.



Here's the puddle after only a minute of the truck running to drive up on ramps :

 

[762mm]

Just got the word from the shop, my issue was a leaking WP (85k miles)....

Well, not that big a deal, I guess.

Ha! What are the odds... we should go for a beer, haha!


My 2014 has 132,000 miles by the way (ex-police truck).