2016 Explorer Mysterious Coolant Leak

[ClassicFord68]

Hello All,

First post to the forums after browsing around and I have a curious case that needs some extra input.

I’ll start off with Saturday,
I went to back up my explorer and the ‘Check Charging System’ light came on. I let the car idle for a little while and checked the battery to which I noticed some corrosion on the terminals. I cleaned everything up and the light went off but I slapped a battery charger on just for good measures and after a few hours I drove around and there were no more lights or issues. I ran some errands and all was fine.

Sunday, I went to change my oil and while under the car draining the pan, I noticed a liquid on the frame rails under the radiator close to the alternator on the passenger side (which would explain the charging system light). I rubbed a little off to see the consistency and smell and it appears to be coolant. I checked my reservoir and it was lower than the cold fill line almost drained and I also noticed one of the AC lines also had the same liquid running down on it. Naturally I start searching for issues. I do not see anything leaking from the water pump weep hole and there are no puddles on the ground. Also the oil was a nice dirty black and no milky white was observed.

I finished up the oil change and topped off the reservoir and went for a quick drive around the block to see if anything was wrong. There was no change in coolant levels, no warning lights, temp readings were normal, nothing on the ground. A few hours later I went back and checked everything again and there is still no noticeable change in the coolant reservoir and nothing on the ground, I let the car idle for a good 30 minutes and observed no coolant leaking.

The only thing I can think of is that on Friday, I was driving for about 2 hours and gave it some hard accelerations and maintained “higher than lawful” speeds for a good duration. My thoughts is that the coolant boiled after turning off the car and coolant overflowed from a pressure release and soaked the alternator and surrounding areas but I’m not even sure if that’s a thing in these systems. Is there a way that coolant can release from the system when overheating like the older, classic cars would do before there were overflow reservoirs? Any input is helpful, thanks in advance.

 

[peterk9]

Welcome to the Forum.

Hopefully, it isn't the water pump. Do you check the coolant level on a regular basis? If, it was a sudden coolant drop I'd be somewhat concerned as it had to go somewhere. I was told one time that the coolant system is a closed system and coolant loss is very rare.

Peter

 

[Fredfishing]

Hello All,

First post to the forums after browsing around and I have a curious case that needs some extra input.

I’ll start off with Saturday,
I went to back up my explorer and the ‘Check Charging System’ light came on. I let the car idle for a little while and checked the battery to which I noticed some corrosion on the terminals. I cleaned everything up and the light went off but I slapped a battery charger on just for good measures and after a few hours I drove around and there were no more lights or issues. I ran some errands and all was fine.

Sunday, I went to change my oil and while under the car draining the pan, I noticed a liquid on the frame rails under the radiator close to the alternator on the passenger side (which would explain the charging system light). I rubbed a little off to see the consistency and smell and it appears to be coolant. I checked my reservoir and it was lower than the cold fill line almost drained and I also noticed one of the AC lines also had the same liquid running down on it. Naturally I start searching for issues. I do not see anything leaking from the water pump weep hole and there are no puddles on the ground. Also the oil was a nice dirty black and no milky white was observed.

I finished up the oil change and topped off the reservoir and went for a quick drive around the block to see if anything was wrong. There was no change in coolant levels, no warning lights, temp readings were normal, nothing on the ground. A few hours later I went back and checked everything again and there is still no noticeable change in the coolant reservoir and nothing on the ground, I let the car idle for a good 30 minutes and observed no coolant leaking.

The only thing I can think of is that on Friday, I was driving for about 2 hours and gave it some hard accelerations and maintained “higher than lawful” speeds for a good duration. My thoughts is that the coolant boiled after turning off the car and coolant overflowed from a pressure release and soaked the alternator and surrounding areas but I’m not even sure if that’s a thing in these systems. Is there a way that coolant can release from the system when overheating like the older, classic cars would do before there were overflow reservoirs? Any input is helpful, thanks in advance. View attachment 446518View attachment 446519

If you have a grill shutter, check if it work well. Mine was broken and still closed with no check engine. During this time I often to top-off engine coolant which magically disapeared.

 

[peterk9]

If you have a grill shutter, check if it work well. Mine was broken and still closed with no check engine. During this time I often to top-off engine coolant which magically disapeared.

The cooling system is a closed system and coolant shouldn't "magically disappear". It has to be going somewhere. The OP didn't get a Check Engine Light. It was a Check Charging System warning.

Peter

 

[Fredfishing]

The cooling system is a closed system and coolant shouldn't "magically disappear". It has to be going somewhere. The OP didn't get a Check Engine Light. It was a Check Charging System warning.

Peter

I know, but after repairing the grill shutter I no longer had to add engine coolant. Repair done 4 years ago. In fact I’m just trying to help with my experience. Anyway, checking that the grill shutter is working properly takes 2 minutes! Engine with turbo and Platinum version don't have it.

 

[ClassicFord68]

Welcome to the Forum.

Hopefully, it isn't the water pump. Do you check the coolant level on a regular basis? If, it was a sudden coolant drop I'd be somewhat concerned as it had to go somewhere. I was told one time that the coolant system is a closed system and coolant loss is very rare.

Peter

I have noticed in recent times changing the oil that the level was visible just below the cold fill line, like I said I looked behind the alternator and didn’t see anything from the weep hole when I was changing the oil, and the spot that the liquid is on doesn’t seem like it would be from that; the spot on the AC hose is higher than the weep hole. I see nothing dripping while the car is running at temperature, or while off. I drove 50 miles this morning and checked the coolant and it still looks to be at the spot I filled up to, and see nothing fresh on the frame and still no puddles. I didn’t really smell anything through the heat and ac. I don’t see any white smoke in the exhaust.

Just some specs for further reference it’s the base 3.5 V6 non turbo and has roughly 167,000 miles on it. Bought it used from the ford dealer in 2018 with 36,000 on it.

If there’s no external pressure release, the only other think for that area is that maybe top hose spit some coolant out… Thanks

 

[ClassicFord68]

If you have a grill shutter, check if it work well. Mine was broken and still closed with no check engine. During this time I often to top-off engine coolant which magically disapeared.

Yes I had seen some posts about that and checked, they seem to be fine. I’m just not sure where the coolant came from and that’s what is puzzling me.

 

[peterk9]

I have noticed in recent times changing the oil that the level was visible just below the cold fill line, like I said I looked behind the alternator and didn’t see anything from the weep hole when I was changing the oil, and the spot that the liquid is on doesn’t seem like it would be from that; the spot on the AC hose is higher than the weep hole. I see nothing dripping while the car is running at temperature, or while off. I drove 50 miles this morning and checked the coolant and it still looks to be at the spot I filled up to, and see nothing fresh on the frame and still no puddles. I didn’t really smell anything through the heat and ac. I don’t see any white smoke in the exhaust.

Just some specs for further reference it’s the base 3.5 V6 non turbo and has roughly 167,000 miles on it. Bought it used from the ford dealer in 2018 with 36,000 on it.

If there’s no external pressure release, the only other think for that area is that maybe top hose spit some coolant out… Thanks

Just keep an eye on the coolant level and the oil. Not all water pump failures had coolant coming from the weep hole.

Peter

 

[ClassicFord68]

Just keep an eye on the coolant level and the oil. Not all water pump failures had coolant coming from the weep hole.

Peter

I’ll be keeping an eye on it for now. It’s just puzzling as to why the coolant is in the spot it’s in and now there’s nothing. It’s one of those flukes that make you paranoid. This is honestly the first major mechanical mystery I’ve had since owning the SUV, everything has just been DIY routine maintenance and tires. I guess I’ll try to do a pressure test when I can and see if that shows anything.

 

[MAS Tequila]

Just keep an eye on the coolant level and the oil. Not all water pump failures had coolant coming from the weep hole.

Peter

Mine didn't have a drop from the weep hole or any other leaks.

The first sign mine had was the dash lighting up and the alarm bells.

 

[bigdude2468]

Regardless of where this leak is coming from if I was planning on keeping this vehicle for any length of time I would have the water pump replaced asap. 167,000 miles is high mileage. The water pump is going to fail, all water pumps fail eventually. Unfortunately if it fails on your vehicle it will likely resulting in the engine being destroyed.

 

[ClassicFord68]

Mine didn't have a drop from the weep hole or any other leaks.

The first sign mine had was the dash lighting up and the alarm bells.

I’ve marked the level in my reservoir with a sharpie and I haven’t seen it lower than the mark, I’ve driven about 200 miles on it now and I still don’t have any other tell tail signs of a leak. The only thing that lit up on my dash was the battery light because I assume the alternator was soaked in the liquid. Which I’m starting to wonder if it’s even coolant now, I swiped my hand across the spot again last night again and it doesn’t smell sweet like coolant. It almost just smells like oil

 

[knikalaska]

If you have a grill shutter, check if it work well. Mine was broken and still closed with no check engine. During this time I often to top-off engine coolant which magically disapeared.

How do you check the grill shutter?

 

[FordFlintrock]

How do you check the grill shutter?

The grill shutters can be observed through the lower grill at front of car. They open and close allowing air to first go through the radiator looking A/C condensor then to radiator which cannot be seen. With engine off you should be able to see the A/C condensor. When started cold with A/C off they should be closed. Turn on A/C which turns fans ON and shutters should be fully open. With A/C off and driving down the road grill shutters will keep engine coolant temp. between 205-215 degrees with varying open and close. If full open shutter cannot lower coolant temp while driving the cooling fans will kick on.

 

[peterk9]

How do you check the grill shutter?

Welcome to the Forum.
I think the above post explains what you're looking for regarding the grille shutters.

Peter

 

[SoCalBrandon]

Hey OP, I just joined the forum - experiencing the same issue. Apologies if I'm resurrecting an old thread.

Any chance you were able to figure out the source of the leak?

I originally thought this was the dreaded water pump failure, but I also noticed the fluid was all the way up the AC discharge hose. I also used a white towel and it seems like the fluid is green in color. My Explorer has the bright orange coolant, so I'm wondering if it isn't coolant after all. Not seeing any fluid above/around the alternator or dripping down from that area (water pump weep hole).

At this point I think it's leaking AC compressor oil (I've read that green dye was added from the factory) from where the discharge hose goes from metal pipe to rubber as shown in your second picture. I attached a picture of the connection point. The rubber hose is greasy from being covered in this fluid. The AC seems to be working fine and not making any noise, so this leak has me thoroughly confused.

Not sure if anyone else has experienced this?

 

[peterk9]

Hey OP, I just joined the forum - experiencing the same issue. Apologies if I'm resurrecting an old thread.

Any chance you were able to figure out the source of the leak?

I originally thought this was the dreaded water pump failure, but I also noticed the fluid was all the way up the AC discharge hose. I also used a white towel and it seems like the fluid is green in color. My Explorer has the bright orange coolant, so I'm wondering if it isn't coolant after all. Not seeing any fluid above/around the alternator or dripping down from that area (water pump weep hole).

At this point I think it's leaking AC compressor oil (I've read that green dye was added from the factory) from where the discharge hose goes from metal pipe to rubber as shown in your second picture. I attached a picture of the connection point. The rubber hose is greasy from being covered in this fluid. The AC seems to be working fine and not making any noise, so this leak has me thoroughly confused.

Not sure if anyone else has experienced this?

Welcome to the Forum.
FYI, the OP was last seen here on November 18, 2023, so probably is no longer following the thread.
I believe you are correct about the green dye. You may have to take it to the dealer to have checked out unless other members can help.

Peter

 

[Steve8316]

Wash the engine thoroughly (you should be doing that at least 2x a year anyway) to remove all residue, then check frequently for the first sign of the leak to pinpoint it. If you're sure it's coming from that hose joint, but the A/C is still working, then it's not worth fixing until there's some other reason to open the refrigerant system. A tiny oil leak won't hurt it. But if the A/C stops working, order that hose (assembly) before going to any shop to get it evacuated, the hose swapped, and then recharged. Nothing else should be replaced (not the dryer or compressor) - at most, an ounce of oil could be added to the new hose to make up for the leak.

It's not on the maintenance schedule, but the clutch air gap should be checked/adjusted every ~4 years. Spec is 0.3 - 0.6mm, and it's adjusted by removing the center bolt, sliding the clutch off the shaft, and removing/changing the shim washer(s) (19D648) inside. This diagram is just a typical compressor:

 

[FordFlintrock]

I originally thought this was the dreaded water pump failure, but I also noticed the fluid was all the way up the AC discharge hose. I also used a white towel and it seems like the fluid is green in color. My Explorer has the bright orange coolant, so I'm wondering if it isn't coolant after all. Not seeing any fluid above/around the alternator or dripping down from that area (water pump weep hole).

At this point I think it's leaking AC compressor oil (I've read that green dye was added from the factory) from where the discharge hose goes from metal pipe to rubber as shown in your second picture. I attached a picture of the connection point. The rubber hose is greasy from being covered in this fluid. The AC seems to be working fine and not making any noise, so this leak has me thoroughly confused.

A refrigerant oil leak in an A/C system is confirmation that a leak is present. Have it repaired sooner rather than later because at some point the loss of refrigerant will prevent the A/C from working.

 

[SoCalBrandon]

Wash the engine thoroughly (you should be doing that at least 2x a year anyway) to remove all residue, then check frequently for the first sign of the leak to pinpoint it. If you're sure it's coming from that hose joint, but the A/C is still working, then it's not worth fixing until there's some other reason to open the refrigerant system. A tiny oil leak won't hurt it. But if the A/C stops working, order that hose (assembly) before going to any shop to get it evacuated, the hose swapped, and then recharged. Nothing else should be replaced (not the dryer or compressor) - at most, an ounce of oil could be added to the new hose to make up for the leak.

It's not on the maintenance schedule, but the clutch air gap should be checked/adjusted every ~4 years. Spec is 0.3 - 0.6mm, and it's adjusted by removing the center bolt, sliding the clutch off the shaft, and removing/changing the shim washer(s) (19D648) inside. This diagram is just a typical compressor:

View attachment 462896

Thank you! I'm wondering if it lost most/all of the oil since the whole front crossmember was coated (just like in the image the OP shared). I read that the compressor only holds around 8 oz. of oil, and I would imagine it would take several ounces to coat the frame and leave a few spots on my driveway as well.

A refrigerant oil leak in an A/C system is confirmation that a leak is present. Have it repaired sooner rather than later because at some point the loss of refrigerant will prevent the A/C from working.

I'm thinking the same. Going to order the hose and take it over to my mechanic to evacuate, replace hose, add oil, and recharge the system. I normally do most service on my vehicles, but I don't have the equipment for servicing the AC system. Thankfully this will be much cheaper than replacing the water pump as I initially suspected.

Thank you everyone for the help and helping me validate I'm not going (too) crazy!