i already searched on the forum, but since i do not have any knowledge about repair, i need you guys help.

just bought 2nd hand 06 mustang coupe auto, 100k milage, the coolant level in the reservior was very low (however no overheat for driving 150 miles), i added it up, couple days late, low again, when they do oil change they found the green coolant is leak, seems not from any tube, from somewhere from the engin house. so far no coolant found in oil. pic uploaded, need suggestion, thanks.

seems leak from the circled area

 

I would check the Thermostat housing. They are made from hard plastice and I have read that they crack easily. Can't tell from the picture but I would also check the water pump for a leak.

 

+1 on the thermostat housing being the 1st possible culprit. It's a chronic issue with the 4.0. Ford made them out of plastic. Attaboy, Ford...

 

thanks for reply.
it should not be sth about head gasket, right? cause mavis tire guy (i did oil change there) told me it is gasket problem.
anything about O-ring (actually what is O-ring)?
if just thermostat issue, i will be happy, cause that would not much. (how much cost normally?) in this case, can i get it replaced myself? i have some tools, but i can't lift the car up.

 

The t-stat housing is a DIY (Do It Yourself) job. BUT, we state that the t-stat housing is the LIKELY culprit. You'll need to inspect for the source of the leak a little harder. If you're not comfortable with repairing it yourself, find a good mechanic (or a reputable Ford dealership, if possible) and be sure to tell them about the t-stat housing.

 

There are a couple of YouTube vidoes on how to change the Thermostat housing if you wish to review them. You can also get a Chilton's manual on your car which has step by step instructions on servicing the car. The only thing is there are both an upper and lower part of the Thermostat housing. Either one could be the issue and you need to look it over really good to determine where it might be leaking.

 

My thermostat housing leaked for over a year. It started as a very slow leak and worsened over the years. The plastic starts expanding due to the heat and starts warping, thus causing the coolant to leak out. I purchased the Upper/lower thermostat housing and the sensor from Autozone. The old sensor's rubber bushing was squished down so much, it would not hold in the new thermostat. I paid around $114 or so. I also bought a couple bottles of coolant and flushed the old coolant out. I had a neighbor friend helpe me install, since he was an ex mechanic and had all the necessary tools. I gave him $40 and a 12 pack of beer. It was a WIN WIN! LOL

 

guys, after research i know what is t-housing now and took this pic from my t-housing, so pretty sure the leak is from t-housing, or at least one leak source is t-housing.



so now that parts to buy? the whole thing incl. T itself also?
buy oem part from dealership or aftermarket? i see aap has it for 38 and aap has always at least 40% off cpn but now sure the aap one fits the oem 100%?
if i get this done by a dealership, how much labor they usually charge (NYC)? or anybody who lives around LI/Queens can do this? i pay for that.

thanks guys for your replies and help.

 

I would check to see if they make an aftermarket t-stat housing made out of aluminum or cast iron. Also, try going with a 180 degree t-stat.

 

Im looking for a metal thermostat housing to fit my 08 mustang 4.0 suffering from the same problem as above. Anyone here of one, please let me know.