hey i have a 2007 v6 4.0 mustang. it has recently been leaking antifreeze and i cant exactly narrow it down. it is in the back of the engine on the drivers side below the valve cover. any info helps thanks!

 

Most likely the thermostat housing. Very common failure on the 4.0. It splits on the back and spews under your intake manifold usually, and makes it look like other problems as a result. There are write ups on the site for how to replace. Easy to do, about a half hour job is all.

 

my leak is coming from the back of the engine and the thermostat housing is in the front. any other ideas?

 

I'm not very familiar with the Cologne 4.0L V6 but there might be a freeze plug on the back of the cylinder head, and that could be the source of the coolant leak.

 

Have you checked the thermostat housing though? Start with the common and simple thing first and make sure. When it spews back under your intake manifold it could look like it is coming from further back on the engine. Eliminate the simple problem before you go looking for a big problem --- and then find out after spending a lot of money that it was the simple common thing that you didn't check first.

 

Thermostat housing...
Water channels back to the rear of the block and actually, the whole valley under the manifold gets saturated with coolant.
By that stage it's really bad, have to add coolant daily.

 

My thermostat housing had a small leak. Had the car on a lift to check out the front strut and saw the water pump was leaking. Replaced the water pump, thermostat housing (upper and lower), fail-safe 195 thermostat, Ford coolant ($35), water wetter (has water pump lube in it) and new dayco serpentine belt.

Good to go - for about 3 weeks then the harmonic balancer started to separate and i then replaced that to. Now i'm REALLY ready to go