What exactly is leaking here? (pics)

[Wheel jack]

This is on the 05 explorer v6 xlt that i bought about 6mos ago to be our family kid hauler. I haven't done any repairs on it yet (and i was hoping i really wouldn't have to) but here we go again...

i found some spots in the driveway - oil/coolant - and assumed it was my 99 ex which leaks pretty much everything. until one day last wk i saw a trail of fresh coolant trickle out from under the center of the engine after my wife pulled her out of the snow.

ugh.

It was almost completely out of coolant and after i refilled it, it leaked about another quart in 100 miles or so. If it wasn't 10 degrees for the last 3 months, i would have noticed this sooner, likely by overheating the engine.

I've got a puddle of coolant and oil sitting under the plastic intake manifold piece. there also looks to be some dried corrosion around that sensor plug near the main line.
any pointers in the right direction would be a huge help. like i said i'm new to this engine but not new to broken fords, haha

 

[bizzs]

The pictures are blown up quite large, but it looks like a freeze plug leak or maybe a cracked block. Try reducing the size of the image and I will take another look.

Bizzs

 

[Wheel jack]

yeah one sec. i re uploaded them.\

 

[swshawaii]

Most common cooling system failure with the 4.0L SOHC is the plastic lower thermostat housing. Usually splits and leaks from the rear facing seams. Use a small mirror and flashlight to check. Confined space but a simple fix. Only parts required for basic repair are a Motorcraft RH148 one sensor housing, upper and lower seals, and replacement ECT sensor o-ring.

http://www.explorerforum.com/forums/showthread.php?t=390690&highlight=lower+thermostat+housing

 

[bizzs]

I reduced the picture and it appears that it might be a freeze plug in front of the motor. I just replaced freeze plugs on a chevy blazer and they were a pain. I had to lift the motor out to replace all of them.

The best advice that I would give is to rent a pressure tester from your local advanced auto parts. My local store just required me to leave a deposit and refunded me in full upon return of the tool. Fill the cooling systems back up with water and pressurize the system and you should see the leak instantaneously. (Just remember to drain the water out completely after the test is complete because the motor block could crack and you would be fubar. )

My Explorer had a faint antifreeze smell and when I pressure tested the system, I found the leak to be a cracked thermostat housing. If it is the front freeze plug, it is not an expensive fix, but can be time consuming and nerve racking getting the plug out and back in. There are some good reference videos on u-tube the can guide you.

good luck
bizzs

 

[Exproblems]

Most common cooling system failure with the 4.0L SOHC is the plastic lower thermostat housing. Usually splits and leaks from the rear facing seams. Use a small mirror and flashlight to check. Confined space but a simple fix. Only parts required for basic repair are a Motorcraft RH148 one sensor housing, upper and lower seals, and replacement ECT sensor o-ring.

]

I second this one above ^! The coolant puddle you have in the pics, is the exact same place where I found the coolant building up after my T-stat housing cracked and split last year. The crack tends to be small at first, leaking slowly, then continues to get larger and spread, leaking greater amounts of coolant.

 

[goodmojo]

I second this one above ^! The coolant puddle you have in the pics, is the exact same place where I found the coolant building up after my T-stat housing cracked and split last year. The crack tends to be small at first, leaking slowly, then continues to get larger and spread, leaking greater amounts of coolant.

One more for the cause. I'm no pro, but I had the same issue these guys are talking about and that's the first thing I thought when I saw the pic. Good luck!

 

[Wheel jack]

thanks for the tips - I replaced the same type of plastic t-stat housing on my 03 focus for the same reason

I cleaned up some of the puddle as far as i could reach under the manifold and i had the truck idling for about an hour with the hood open to have a look around. Although it did not seem immediately obvious that this is where the leak is originating from - I'm going to drive it as normal this week and keep an eye on it for more signs of leakage.

 

[Wheel jack]

I reduced the picture and it appears that it might be a freeze plug in front of the motor. I just replaced freeze plugs on a chevy blazer and they were a pain. I had to lift the motor out to replace all of them.

The best advice that I would give is to rent a pressure tester from your local advanced auto parts. My local store just required me to leave a deposit and refunded me in full upon return of the tool. Fill the cooling systems back up with water and pressurize the system and you should see the leak instantaneously. (Just remember to drain the water out completely after the test is complete because the motor block could crack and you would be fubar. )

My Explorer had a faint antifreeze smell and when I pressure tested the system, I found the leak to be a cracked thermostat housing. If it is the front freeze plug, it is not an expensive fix, but can be time consuming and nerve racking getting the plug out and back in. There are some good reference videos on u-tube the can guide you.

good luck
bizzs

Just our of curiosity, where are all the freeze plugs located in this engine so that i could inspect them?
I just had to go and research what they are.

 

[bizzs]

wheel jack,

there are many locations of those freeze plugs on the engine block. The purpose of those plugs are designed to crack if the block freezes up from having the wrong antifreeze mixture. Before putting the cart before the horse; I would do a pressure test on the coolant system. I would rent the pump so you can diagnose exactly what is leaking. Attach the pump to the coolant bottle and pump air to specs. I guarantee that you will hear a hissing sound of air and detect where the coolant is leaking from. It will save you a lot of time and guess work.

I hope for your sake that those freeze plugs are not the problem because that is a job replacing them. Usually when one is cracked open you will find another one that is deteriorating, or cracked too.

Those chevy blazers have no room to work and I actually had to lift the motor out. I had one hell of a time with that project getting them out. The good part is that the freeze plugs were only 2 bucks a piece, but I probably would of had to pay 1000 or more in labor time.

Good luck,
bizzs

 

[Blacksheep Josh]

Thermo housing broski!

 

[Rickademus]

My 05 Explorer is leaking in the same place.
Is you explorer still leak free after you fixed it?