hi all
i recently bought a 1999 2 door mustang with the 3.8 v 6 for my granddaughter 17th birthday present. or curse !? haha

any way any help would be appreciated:

it has high miles 150k +

runs real well, but is loseing anti freeze , found one leak and replaced hose,
i cant find any other leaks or even traces of a leak, but it will use a gallon every
200 miles , sometimes faster,,, no signs of it being in the oil,,, or anywhere

sugestions of where to look will be appreciated

thanx in advance

jba

 

Welcome, if you see no signs of external leaks and no "milky" oil, then about the only other place for it to go out of the exhaust.
Its not that uncommon for a motor to burn coolant along with the gas and air mixture, you could have a small leak into a cyl and as long as its not a lot of coolant the engine will burn it just fine, until the little leak gets bigger.

 

tuff4.6
thanx for the reply
no milky oil,, i kind of was thinking it may be burning the coolant,

would you think it be a head gasket ? or is it possible that the intake manifold gaskets bad or the manifold is cracked ?

any suggestions on how to proceed to isolate this ????

 

Yes sir, I would start first with pulling the plugs and check each one for signs of anti-freeze or water. Next, rent a radiator pressure tester from auto parts store and pressurize the cooling system to about 15 psi with the engine COLD and check for leakage, then start the motor and get it up to operating temp and then presusize it again and see if there is a noticable different in leakage. If there is a big difference then I would say its a gasket (either head or intake)

If you stand at the rear of the car with it running do you smell anything like anti-freeze? Do you smell anything inside the car or are the carpets wet on the passenger side (heater core?)

Try this and let us what you find and we go from there. Don't add anything into the system like "stop leak" or anything like that right now until we find the problem.
Good Luck!

 

tuff4.6
thanx again for replying

carpet is not wet,,,, but she says her heater will blow hot then cold then hot...?
looks like the lines run from the intake to firewall---- need thermostat?? or maybe just from coolant lose ???

we live 70 mile from town so running in to town dont happen often

i set my compressor to 10 psi and hooked it to the over flow hose, no leaks that i could see.. so i started engine and the service light came on .. it did start running a little rough till it warmed up. still no leaks,
a friend has a code reader and it read 1 code--- #6 injector , so i am guessing it caused a miss from antifreeze going into cyl. ????? after reset the light has not come on.
so now i am guessing it is a head gasket ? or cracked head ?
but would a cracked head leak worse when hot ?
and a bad gasket seal when hot ??
i am thinking of trying to retourqing the head..! ?
she had to take it to work today, so tomarrow i will let her take my truck..
and do some more checking.

any more help and ideas are greatly appreciated

thanx
jba

 

Sure sounds like coolant is getting into the cyliners. That was very smart on using the air compressor for the pressure test.

Yes, leaks will become worse when the motor is hot because the metal expands and opens up "cracks" and contracts as it cools.

I don't think you have too many options from here, either try some "snake oil" like "stop leak" (not recomended) or pull the intake (check gaskets there) and reassemble and add 10 more foot pounds of torque to head bolts and hope that fixes it or just go ahead and pull the heads and replace gaskets and know for sure. Good Luck!