Coolant leak

[glo81]

This past weekend, I noticed a rather moderate sized puddle of coolant underneath my car in the garage. Attached are pictures from underneath the car where it seems to be coming from (blue arrow). The coolant seems to drip down from where the blue arrow is to the bar in the second picture (yellow arrrows). Any ideas what is likely the culprit? Bad hoses? Radiator issue?

 

[SyberTiger]

The leak could be coming from a lot of places...could be hoses, could be water pump, could be radiator, could be intake manifold. You're going to need to to inspect a lot closer to see if you can discover the leak. I'm guessing you have a 4.6L V8. Have you changed out any of those component before and how many miles on your vehicle? I've replaced the radiator and intake manifold because of leaking that was visible.

 

[imp]

@glo81 My leakage was exactly the same. I have the 4.0L. Could not confirm that it was the water pump until the belt and pump pulley were removed. The top of the pump is then exposed, revealing a large "weep" hole on the top. There was evidence of lots of evaporated liquid there. But since the puddles came and went over several month's time, and no liquid coolant visible, I concluded at 160K the pump ought to be replaced, which I did. No puddle for a number of days, then it reappeared. Very close inspection revealed the original leak source: the gasketed seam between the two halves of the thermostat housing, where wetness was definitely present, and coolant was present standing in the "Vee" behind the housing. The whole story is here: Coolant Leak Screw-up '04 4.0L

 

[glo81]

@glo81 My leakage was exactly the same. I have the 4.0L. Could not confirm that it was the water pump until the belt and pump pulley were removed. The top of the pump is then exposed, revealing a large "weep" hole on the top. There was evidence of lots of evaporated liquid there. But since the puddles came and went over several month's time, and no liquid coolant visible, I concluded at 160K the pump ought to be replaced, which I did. No puddle for a number of days, then it reappeared. Very close inspection revealed the original leak source: the gasketed seam between the two halves of the thermostat housing, where wetness was definitely present, and coolant was present standing in the "Vee" behind the housing. The whole story is here: Coolant Leak Screw-up '04 4.0L

Thanks for the info, imp. I took my car to my family's long-time mechanic across the street from my work this morning and he said it was indeed the thermostat housing (as well as the lower hose on the bottom that needed replacement because it was cracked/cracking, which I knew because coolant occasionally drips from there). He quoted $190 for the repair (parts and labor), which seems reasonable from my cursory searches. We've known him a long time so he's not one to mark up prices for a job (at least I don't think).

Edited to add: Mine is a 4.0L as well.

 

[IIGood]

The problem with coolant leaks, at least in my experience, is that you never really know where it's truly coming from just by looking at it.

On my '03 GT a few years ago, there was a coolant leak. I didn't know it but the car overheated on me one day in the middle of August. Found the reservoir to be bone dry and even after dumping in a gallon of coolant, there was still nothing in the reservoir. Turned out that there was a small crack on the intake manifold where the plastic met the crossover passage for the thermostat housing.

Then a few years later, I thought the radiator had a leak...it just decided to spew it's contents on the road. When I would go to pour some coolant in, it would just drain right out of the bottom of the radiator, or so I thought. I replaced the radiator but upon inspection of the old unit, I didn't see anything to indicate there was something that would cause a leak...no cracks on the end tanks, no holes, nothing. It's been fine ever since, fortunately, but still odd.

Now I just let the shop deal with any leaks that come up. They've got the tools to find it.

 

[IIGood]

Thanks for the info, imp. I took my car to my family's long-time mechanic across the street from my work this morning and he said it was indeed the thermostat housing (as well as the lower hose on the bottom that needed replacement because it was cracked/cracking, which I knew because coolant occasionally drips from there). He quoted $190 for the repair (parts and labor), which seems reasonable from my cursory searches. We've known him a long time so he's not one to mark up prices for a job (at least I don't think).

Edited to add: Mine is a 4.0L as well.

Sounds about right. The housing on my previous Explorer, a 4.0L as well, was replaced and it was around the $200 mark P&L. The part itself is fairly cheap from what I saw but factor in the replenishment coolant, labor, etc.

 

[glo81]

The problem with coolant leaks, at least in my experience, is that you never really know where it's truly coming from just by looking at it.

Now I just let the shop deal with any leaks that come up. They've got the tools to find it.

Yeah at this point, the Explorer is 15 years old and has 172,000+ miles on it (no major issues during its run--knock on wood), so I'm perfectly okay with having the shop deal with leak problems and then deciding if the repair is worth the cost.

That's really strange how your GT ended up dumping all that coolant mysteriously. I have a '14 GT and hopefully that isn't something that happens to me in the future (and that this car is as trusty as the Explorer has been).

 

[Tech By Trade]

That sucks, the 4th gen you can change it by 3 bolts. Its a 15 minute job. The intake manifold is farther back so you don't have to remove it to get at the housing.