Strange coolant leak issue, any ideas?

[TheDoug]

So my 2018 platinum 4x4 has done this a total of three times. Once over a year ago an twice within the last three months. I get home, park it and come back hours later (or overnight) and there is a puddle of coolant on ground. It seems to dump a certain amount and then it stops. I fill the reservoir and drive and the level stays constant until this thing happens again.

The puddle appears to be coming from the middle skid plate, maybe near the heat exchanger for transmission?? Never get a good look because of all the skid plates.

Anyone come across this before?

Edit: attached puddle size pic

 

[professorfrey]

I have this same problem with the same vehicle, except mine is now leaking daily and quite a lot. Following this thread in hopes that someone has an answer. I've had the water pump and thermostat replace and it only seems to have gotten worse.

 

[TheDoug]

I have replaced the thermostat as well and it's not coming from that.

Is your leak toward the front of vehicle or more middle where engine and tranny meet?

 

[professorfrey]

I believe more toward the front. It's hard to tell where it's coming from because the fluid slides down through who-knows-where and then drips to the ground right around the area where the oil filter is located. I don't really know part names, but there is an iron shield on the very bottom of the truck and that's where it's dripping from.

Another thing that I find strange is that something it just doesn't leak. Like I can drive it for 10 minutes and park it and have nothing. Then later in the day, I'll drive a similar distance, park it, and and discharges over half of the reservoir.

 

[TheDoug]

Sounds like it's the same spot... Metal shield with the little square cut in it...

Luckily mine is not dumping that much but it's the same scenario... Drive for 6 months no issue... Then one day I park and it dumps. So strange

 

[GlennSullivan]

Could be cracked or leaking hoses going to the turbos or heater core. Doug you are going to need to temporarily remove those skid plates to find.

Professor you may have to remove the soft covers under the engine to find your leak.

Read this thread. Solution starts at post 6

Bad Radiator Cap? / Coolant Disappears

I encountered a coolant disappearing issue with my 2019 Expedition Max with 50,000 miles. I routinely check my fluids, and two weeks ago, I noticed the coolant reservoir was low and had to add about a quart of coolant. Today, I checked it again, and to my surprise, the reservoir was almost...

www.expeditionforum.com

 

[TheDoug]

Good info on the video. Gives me some places to look but mines so weird that it doesn't leak all the time. I feel like the tech in video is saying these problems spots just leak constantly when the wear out.

 

[bobward757]

Have you had the Shop do a pressure test yet? If it’s the fittings on the hoses that go into the radiator pressure test will show those instantly.

Good luck. Keep us informed

 

[Jerald Cook]

I had a leak in the coolant tube that connects to the driver's side turbo. Could be dripping down the turbo/exhaust and migrating from the actual source of the leak.

 

[md540i]

I didnt have time to look at that link yet, but I had a very similar issue with my 2018 Exp Max Limited.

Mechanic told me that it was a cooling pipe to the turbo leaking, there was a small crack in the pipe...the pipe is about $700 or so but the issue is that you basically need to pull the engine in order to replace this pipe as it is one contiguous y pipe that feeds both turbos from underneath the motor.

He suggested to sell the truck asap. To be honest I was looking to replace the vehicle anyway as I had about 60k miles and was having other issues with it. So that's what I did, he put sealant in the cooling system and I traded it in on a new 23 Exp Max Platinum leftover that I got a really good deal on.

Side note, found out the hard way that the 23 platinum's are missing a bunch of features due to supply chain issues, the Multicontour seats, kick to open tailgate, auto park and a few others.

Anyway just wanted to report my experience, luckily I was already on the fence for replacement so it wasn't a huge issue for me. Hope you have better luck.

 

[ROBERT BONNER]

Many of these trucks have experienced a "cab off" service of VCT, 10R80 or turbos in their history. When the body is separated from the frame and then reattached, one of the most difficult connections to reattach is the rear heater connections located on the passenger side, cleverly hidden under the PCM connections and behind the under hood fuse/distribution block against the dash panel (firewall). My neighbor's 2019 developed a leak as described above that went on for years before we found it and fixed it by replacing the "Y" hoses. The Dealer hadn't quite clicked the positive retainer on one of them. The hose sealed well enough to prevent leaking until "afterboil" once the truck was shut off.

Best way to check is to wait for 30 minutes after hot shut off and feel the hoses (blindly) for dampness.

Good luck.

 

[JimmyC]

I had a similar problem on a F-150, found out the O-rings in part of the coolant system was leaking. When the tech did pressure tests it would push the O-ring onto the surface a seal the leak. Replaced all the O-Rings and problem solved

 

[BlackBetty]

Looks like someone already mentioned it, but I’ll chime in as well. Had a mystery leak on my 2016 on the passenger side. Found coolant residue on my passenger turbo coolant line.

Bought new O-ring, snap-ring, and fitting to replace faulty parts. However, got everything apart only to find no sign of leaks from the coolant line/ turbo mating surface.

After careful inspection found that coolant was actually coming from the driver side turbo fitting and running down the line and dripping on the passenger side line. SMH!!!

Anyway, got the line, fitting, O-ring, and turbo removed. Replaced the faulty components. Never had any more issues until I got rid of it. Think I did it around 2020/21 timeframe.

Not too fun. Not too hard either if you have the right tools, and a lift. I had both.

 

[TheDoug]

Thanks for the info on your experience.

 

[ManUpOrShutUp]

He suggested to sell the truck asap. To be honest I was looking to replace the vehicle anyway as I had about 60k miles and was having other issues with it. So that's what I did, he put sealant in the cooling system and I traded it in on a new 23 Exp Max Platinum leftover that I got a really good deal on.

I get not wanting to deal with the issue, but dummying it up to hide it from the buyer is not only really scummy, it's actual fraud. Some other person is now going to get saddled with it.

 

[VBreithaupt]

You may not have the leak if the vehicle doesn't reach normal temp. and pressure. I had a common hair line crack in one of the plastic hose unions ( search forum) that didn't have a noticeable leak. You could smell it but no puddles. A pressure test would help identify the leak. The turbo cooling lines had more issues in the older models. Not sure if its as much an issue now that they reengineered the lines.

 

[TheDoug]

Found my issue

Water pump has really really slow leak and it doesn't do it all time... But finally caught it today

At top of picture you see the coolant drops

 

[20EBXLT]

Check the "Y" fitting at the heater core hoses. This is where mine was leaking from. I kept noticing that the overflow tank was running low but would never see coolant on the ground. I found out it was basically leaking down onto the turbo and burning off!

That Puddle Under Your Expedition? Here's Exactly What's Wrong | DIY Fix Heater Hoses

Struggling with a coolant leak on your Ford Expedition with the 3.5 Ecoboost engine? In this video, we show how to diagnose and fix heater core hose leaks. F...

youtu.be

Edit: just saw you posted that you found it @TheDoug. had this thread up for a little bit but never hit reply.

 

[Calidad]

The fittings used on cooling lines related to the turbos have been a known problem. 2019’s got a updated connector but it sounds like the updated fittings were still a problem but not as bad. I read somewhere that there’s an even newer fitting design being used since the 2019 revision.

My understanding is that three things done and the 3.5 is pretty solid.

The crap cam phaser issue the new version is apparently solid
Replace the known leaky coolant fittings with the new upgrade versions

And swap out the plastic timing chain guides for the 5L Coyote metal guides apparently the same exact part only metal.

Then the 3.5 is pretty much bulletproofed.

The 10spd? Yeah I got nothing it seems like parts quality inconsistency is a big factor in the 10spd problems.

GM is having problems with it also but shift selinoid related lost gears fixed with new bits replaced in the
transmission etc.

All of these issues between both brands seem to be parts quality issues with some design factors that enhance the parts quality issue.