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