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?