Radiator leak / coolant disappearing

[DavidC]

Hi, I have a 2018 with 62,000 miles. My coolant is going somewhere but I can't determine where. I fill the overflow so that it's between the min and max lines and I can drive 50 miles, let the engine cool off, and my coolant has dropped 1.5 to 2 inches, which is about an inch below the min line. I've let it idle for 8-10 minutes and there are no visible coolant leaks. Engine temperature gauge isn't increasing beyond it's normal temp, but the fan will turn on, which is something new and which is how I knew something was wrong. It drives normally, there's nothing abnormal with the exhaust color, no burning smells, nothing odd that I can detect. But that coolant is going somewhere...hopefully not past the head gasket and into the engine oil. Any advice or help?

 

[Don Hall]

You can tell immediately if coolant is entering the oil system .... milkshake colored oil. Start with pressurizing the radiator. Simple test tool that replaces the rad cap. A deformed rad gasket will allow coolant out, and not be noticed due to evaporation. Check to see if coolant siphons back to the reservoir during cool-down. If not, there is a break in the closed system. An additive to coolant will show under a UV light if there is a leak.

 

[99WhiteC5Coupe]

Hi, I have a 2018 with 62,000 miles. My coolant is going somewhere but I can't determine where. I fill the overflow so that it's between the min and max lines and I can drive 50 miles, let the engine cool off, and my coolant has dropped 1.5 to 2 inches, which is about an inch below the min line. I've let it idle for 8-10 minutes and there are no visible coolant leaks. Engine temperature gauge isn't increasing beyond it's normal temp, but the fan will turn on, which is something new and which is how I knew something was wrong. It drives normally, there's nothing abnormal with the exhaust color, no burning smells, nothing odd that I can detect. But that coolant is going somewhere...hopefully not past the head gasket and into the engine oil. Any advice or help?

I’d bet your water pump is leaking slightly, while the engine is running.

The vehicle may have to be put on a lift to examine the pump and see if there is dried coolant residue.

 

[DavidC]

 

[DavidC]

Thanks for the replies. Points of interest:
1. That’s my current coolant level and it does not go below that level.
2. After 10 minutes of idling, my exhaust drips once every 6 seconds. My sister’s Chevy Captiva dripped twice in one minute. Exhaust pipe angle could play a role.
3. I can’t discern a change in oil color. Looks normal to me.
4. There are two 8 inch diameter wet marks under the vehicle. One presumably is from the AC and the other? Water pump as someone suggested, perhaps? Both were clear, not orange.

 

[99WhiteC5Coupe]

Thanks for the replies. Points of interest:
1. That’s my current coolant level and it does not go below that level.
2. After 10 minutes of idling, my exhaust drips once every 6 seconds. My sister’s Chevy Captiva dripped twice in one minute. Exhaust pipe angle could play a role.
3. I can’t discern a change in oil color. Looks normal to me.
4. There are two 8 inch diameter wet marks under the vehicle. One presumably is from the AC and the other? Water pump as someone suggested, perhaps? Both were clear, not orange.

Although you have a 4th generation and I have a 3rd generation with the 3.5 Ecoboost - the cooling system, hoses, water pump and degas bottle are very similar.

I had leaking coolant hoses (replaced under Ford’s ESP) and a leaking degas bottle (replaced under Ford’s ESP). The bottle had a crack at the point where the rubber hose connects to the bottle (where there is a metal reinforcement insert). The bottle would only leak if the hose was wiggled at the fitting.

The water pump later leaked slowly, and only while driving. The coolant level went down very slowly, and I had no residue on the ground when parked.

It took two trips to the Ford dealer for a correct diagnosis and repair. The first trip they pressure tested the coolant system with the engine off - and declared there was no leak.

The second trip I insisted the engine be examined from underneath (I had four surgeries and can no longer crawl around under cars). The service advisor said the mechanic quickly found the leak, as there were coolant residue marks around the water pump. This was at 70,*** miles (purchased new).

From other posts on this forum, it seems the Ecoboost water pump is prone to failure between 65,000 - 80,000 miles.

 

[studabaker]

An indication of a head gasket failure is if there is oil in the Coolant, so I would say that does not appear it. Also the leak could be anywhere until it is found... the water pump on my 2nd gen is right in front and it would have to break the seal to the block which may have happened. The weaker points are hoses, resevior, even thermostat. You should replace your thermostat every once in a while. It should be easy and cheap. If that is not opening... You could have gotten it kinda hot once or taken some damage from debris that could have punctured a hose. A punctured hose seems most probable and could leak under load and not at idle... if you got it hot the water pump seal could have failed. Mine is behind the alternator, and runs on the same belt. Take the belt off and the alternator and there it is... condensation on hot surfaces is normal. exhaust condensation may be nothing. If your exhaust pipe is getting hot the moisture in the air is condensing on it... you would have white smoke if you had Coolant in your exhaust pipe.

The uv thing and the pressure test are promising. Get it hot and then check for uv stuff. Check that the connection points are tightened such as from radiator to hose, the hose clamp, the hose to the block.

You could drain your Coolant and pull the hose and put it back on with a sealant. Let that dry at least 4 hours prior to testing it. And the thermostat are all pretty cheap. The lower hose may have taken damage. Have someone crawl under there with the pressure cap on (rental tool at parts store) PUMP IT UP Carefully when you suspect a leak. Avoid hot Coolant to the face, or anywhere else.

 

[ExpyNole]

coolant won't drip out the exhaust. It'll come out as whispy steam and dissipate. That drip out your exhaust is the cat converters working.

 

[HISHONOR]

2018 with 88,450 miles and just had to replace two heater hoses. Same symptoms as you describe. Coolant level decreased slightly daily. Couldn’t see anything until put up on a lift.

 

[99WhiteC5Coupe]

Thanks for the replies. Points of interest:
1. That’s my current coolant level and it does not go below that level.
2. After 10 minutes of idling, my exhaust drips once every 6 seconds. My sister’s Chevy Captiva dripped twice in one minute. Exhaust pipe angle could play a role.
3. I can’t discern a change in oil color. Looks normal to me.
4. There are two 8 inch diameter wet marks under the vehicle. One presumably is from the AC and the other? Water pump as someone suggested, perhaps? Both were clear, not orange.

What have you determined or resolved?

 

[DavidC]

I think it goes like this:
Coolant was legit low and auxiliary fan turned on, which was my indication.
I put coolant in so that it was between the min and max lines as seen in the overflow reservoir.
Coolant went out such that it was below the min level.
I re-filled so it’s between min and max lines again.
Again coolant went out such that it fell below the min line.
I think the excess coolant after both refills went out both times through the overflow hose until it “had what it needed” (even though it appears low).
Fan has not turned on again.
So if the fan doesn't turn on then I’m fine with coolant being below the min line.
I may stop at a Ford dealership and ask to pop some hoods and see what others look like.

 

[Bmanxx13]

I had the same issue and had it fixed under warranty a couple months back in my '18. Dealer replaced a bunch of parts. From what I remember they replaced water pump & gaskets, cooling/radiator hoses, thermostat housing, and probably some other stuff that I can't remember. Haven't had any coolant issues since.

 

[DavidC]

Thanks for the info. Do you happen to know the mileage. I'll have to see if I'm still under warranty.

 

[mr_dave]

I had a similar issue twice on my 5.4L. Once was because the (plastic!) coolant crossover gasket was broken and leaking coolant into the engine block valley, under the intake.

The other time was a bad radiator cap that would leak a decent amount of coolant under hard acceleration when the engine was hot. New cap fixed the issue.

I know it's a different engine but the cause could be similar.

 

[Matthew Jenkins]

Mysterious coolant leak. Look under your oil fill cap. a little creamy substance is normal if you don't drive much, but that forms over a few thousand miles. If you have quite a bit in a short time that can mean coolant in the oil. That could mean a head gasket or cracked head. This is an extreme case. Search for source first. If it is leaking near something hot it could be evaporating before dripping.

 

[coyote-dogfish]

I am having identical symptoms with my 18 Expedition MAX Platinum with 52k miles. I haven't gotten under it yet to see where it's leaking, but I'm losing some each time I drive. My car has had an alarming number of problems and has lived at the dealership. Had the 10A transmission replaced (warranty thank God) about 10k miles ago due to complete failure. A/C problems (evap leaking in the rear? dealer still troubleshooting), electrical problems, had the crazy mirrors and seat memory position problem (fixed with a reprogram), rear defroster failure, buggy electronics interface, etc. Recently I was driving and the phone was ringing in the car and kept ringing no matter what I did. I even shutoff my phone. Car was still ringing... had to stop the car along the road and restart! Random error codes one day saying "See Manual" "Pre Collision Assist not Available" - ran in limp mode the rest of the way home... cleared on its own after a restart?? Rear Parking brake failure, sunroof guide rail broken wouldn't close, rear defroster broke, etc. All with under 55k miles! Ughh sorry to rant but I'm just so disappointed in the car overall. I want to love it - but we're beginning to hate it!

 

[DavidC]

Sorry you've had bad experiences. Overall, I really like my '18 Exp Limited. I'd buy another one. As for my original post on the coolant leak...my coolant goes somewhere. When I got the oil changed a few months ago, I asked them to look for the milkiness and they said the oil was normal looking. So I put coolant in to raise it to the MAX line and in about 8 weeks it will reach the MIN line and I'll add coolant to raise it back to the MAX line and I'm fine with doing that.

 

[coyote-dogfish]

Sorry you've had bad experiences. Overall, I really like my '18 Exp Limited. I'd buy another one. As for my original post on the coolant leak...my coolant goes somewhere. When I got the oil changed a few months ago, I asked them to look for the milkiness and they said the oil was normal looking. So I put coolant in to raise it to the MAX line and in about 8 weeks it will reach the MIN line and I'll add coolant to raise it back to the MAX line and I'm fine with doing that.

Yeah thanks - as an engineer I know that it's not as simple as just saying it's a "lemon" - there is a root cause for each failure. So far it's all been programming/software and faulty components and/or design issues. My favorite was hitting the memory seat preset and having the mirrors start going in and out endlessly like they are in panic mode, and then ratcheting/clicking endlessly??! haha Like... ... really??? There are many posts here about that one and sure enough a reflash of the DDM/PDM (there's a TSB I forget what it is now) fixed that. I'm a lifelong Ford fan and I have a Mustang with a Coyote that I built, but between my Flex, and my last expedition, and this one... man... Come. On. Ford.

 

[DavidC]

Well, there are other girls in town. I bought mine, since at the time, it was the most technologically advanced full-sized SUV available. None of the other automakers had refreshed or redesigned their large SUVs. Though I said, I'd buy another one, and I would, I would start my research over again since Chevy has since re-designed the Tahoe/Suburban/Yukon and by now one of those, or some other SUV, may be better than today's Exp.

 

[mr_dave]

Yeah thanks - as an engineer I know that it's not as simple as just saying it's a "lemon" - there is a root cause for each failure. So far it's all been programming/software and faulty components and/or design issues. My favorite was hitting the memory seat preset and having the mirrors start going in and out endlessly like they are in panic mode, and then ratcheting/clicking endlessly??! haha Like... ... really??? There are many posts here about that one and sure enough a reflash of the DDM/PDM (there's a TSB I forget what it is now) fixed that. I'm a lifelong Ford fan and I have a Mustang with a Coyote that I built, but between my Flex, and my last expedition, and this one... man... Come. On. Ford.

Unfortunately, this is what happens when companies try to manufacture very complex things as cheaply as possible on a global scale. Just look at the Boeing 787 debacle.