desperate for help w/coolant leak

[DC Dave]

2006 explorer 4.6l v8 3v. Just replaced radiator and thermostat. Filled radiator w/ 50/50, filled resovoir to cold line w/50/50. Vehicle on level ground, started up, ran for 10-12 minutes, all seemed ok, then noticed significant coolant leaking from between motor and trans, leaking out more on left side like over the left rear corner of oil pan. Also seemed to be coming from inside the flywheel cover(if I'm describing that correctly), that leak also seemed to be more on the left. Further inspection seemed to show a slower coolant leak coming from below the main pulley that is below the water pump. Any ideas as to possibilities of leak origin would be most appreciated. Wondering if there's a freeze plug in the rear of the block or if a water pump leak could somehow be funneled to the rear of the motor. I'm nearing desperation and any help would be greatly appreciated. Thank you

 

[DC Dave]

2006 explorer 4.6l v8 3v. Just replaced radiator and thermostat. Filled radiator w/ 50/50, filled resovoir to cold line w/50/50. Vehicle on level ground, started up, ran for 10-12 minutes, all seemed ok, then noticed significant coolant leaking from between motor and trans, leaking out more on left side like over the left rear corner of oil pan. Also seemed to be coming from inside the flywheel cover(if I'm describing that correctly), that leak also seemed to be more on the left. Further inspection seemed to show a slower coolant leak coming from below the main pulley that is below the water pump. Any ideas as to possibilities of leak origin would be most appreciated. Wondering if there's a freeze plug in the rear of the block or if a water pump leak could somehow be funneled to the rear of the motor. I'm nearing desperation and any help would be greatly appreciated. Thank you

Apologies for posting this issue twice. Originally mistakenly posted in the new member forum. Not new to the site but new to posting(in the right place)

 

[DC Dave]

Apologies for posting this issue twice. Originally mistakenly posted in the new member forum. Not new to the site but new to posting(in the right place)

Update: There's no fluid leaking from the rear of the motor, but the leak below the main pulley that is directly below the water pump is steady dripping. Very difficult to tell but it seems that this leak is coming from the water pump. I'm ready and willing to replace the water pump but hesitant if the previous leak at the rear of the motor is potentially a much larger repair...

 

[Mr. Alligator]

Did you replace the thermostat housing? The plastic thermostat housings had common failures at several points, and the leaking coolant runs down the valley between the two cylinder banks. Even new, and even OEM, the plastic housings are prone to failure. Simmons Motorsports makes an excellent aluminum thermostat housing that resolves this issue.

The thermostat housing replacement is a reasonable two or three hour project. Sounds like you may have a water pump issue also. In my opinion, the water pump replacement is the more difficult issue, but both can be done yourself.

Freeze plugs are an unlikely source of either problem.

Good luck!

 

[DC Dave]

Did you replace the thermostat housing? The plastic thermostat housings had common failures at several points, and the leaking coolant runs down the valley between the two cylinder banks. Even new, and even OEM, the plastic housings are prone to failure. Simmons Motorsports makes an excellent aluminum thermostat housing that resolves this issue.

The thermostat housing replacement is a reasonable two or three hour project. Sounds like you may have a water pump issue also. In my opinion, the water pump replacement is the more difficult issue, but both can be done yourself.

Freeze plugs are an unlikely source of either problem.

Good luck!

Thanks very much for the reply. My thermostat housing is aluminum and I see no leaks there.

 

[Bill MacLeod]

Have you pressure tested the cooling system? Testers are probably available to rent from Advanced or Autozone. Also a very usefull tool to have in your tool box and not very expensive.
The heater hose lines run down the firewall on the passenger side and crossover to the left rear for the rear seat heating system. The small hose clamps are known to rot/corrode and lose their tension Causes leaks that are very hard to diagnose at times.
T/stat housing cracking is a V6 issue and does not apply to the V8 engine.

 

[Blackhawkxx]

You said that you "Just replaced radiator and thermostat." Unless a really strange coincidence happened, it must be from the area that you worked on. A tester is a good idea.
You also said "but the leak below the main pulley that is directly below the water pump is steady dripping." I would be looking at the lower radiator hose connection. It is stuck up there pretty far.

 

[JDMB]

Did you replace the thermostat housing? The plastic thermostat housings had common failures at several points, and the leaking coolant runs down the valley between the two cylinder banks. Even new, and even OEM, the plastic housings are prone to failure. Simmons Motorsports makes an excellent aluminum thermostat housing that resolves this issue.

The thermostat housing replacement is a reasonable two or three hour project. Sounds like you may have a water pump issue also. In my opinion, the water pump replacement is the more difficult issue, but both can be done yourself.

Freeze plugs are an unlikely source of either problem.

Good luck!

I just replaced the thermostat assembly housing on my 2003 Ford Sport Trac. Mi too was leaking and water was running down the back of the motor. Fixed my leaks. Repaired myself for around 50. dollars.

 

[Explorer_PL]

When you say left, is it driver's side ? 4.6 are famous for leaks from the Y connector for rear heat. But that's on the passenger side by the exhaust manifold.