Guys,

I just want to get some confirmation before I dive off and replace my head gaskets.

I noticed a coolant leak from the back side of the motor behind the intake. I can't get a real good look at exactly where the coolant is coming from but it appears to be streaming down the backside of the heads. It is clearly not coming from the heater core so my conjecture is that it is either a head gasket or freeze plug.

There is no water in the oil and I can't detect in oil in the coolant.

Is there a sensor or some other plumbing on the backside of the motor that I am unaware of?

The motor has about 150K on it so should I bother replacing the head gaskets or just get the motor rebuilt?

 

It makes me feel bad when someone gets no response for help with something that is really important. I guess you need to upgrade something to get any help.

First, I would not pull the heads and think the worst. Check your water pump and hoses. I know they are not in the back, but so many times people just want to assume the worst. Even a leaky water pump can have water blown onto the heads and run all the way back and leak. Some times you cant find the trail of water because the heads get so hot it evaporats before you can see it. Look for discoloration of trails from your pump to the place where you see the water. Follow it backwards and forwards to the front and rear. Look for any suspicouse marks, trails or discoloration. Good luck and let us know what you find.

 

Thanks for the reply.

One of the main reasons I initiated the thread is for the same reason you bring up. I know I am assuming the worst and was just searching for any other explanation other than what I know it is.

Your advice regarding the water pump is a good one and I'll give the motor a thorough going over before I make the determination to pull the heads.

It seems to leak even before the motor gets very hot so if water is coming from somewhere else and draining back to the rear of the motor then it should be visible.

Thanks again.

 

i was kind of hoping someone would post right away with great insite but it doesnt always happen that way. poffutt has a good point with the water pump. anouther thing to think of is the intake manifold. intake manifolds have cross over tubes that flow with coolant in the front and back of the intake. it is a less costly and much easier repair than removing heads. frost plugs dont usually spray up to the heads but i guess anything is possible. a good way i have checked these things is to get a good flash light and a mirror and reflect the light and image into the mirror and you should be able to get a decent look at the back of the heads and intake.

 

A mirror was my next step.

I'll let you guys know what I find.

Thanks for the replies.

 

i had a similar problem on a truck i used to drive it had a 351w, the rear water passage on the passenger side of the intake gasket was leaking you might check that.

 

I thought the same.

 

A dye to add to the coolant is available that will flourese (sp?) under a black or ultraviolent light. That might help you follow the trail.

 

Did you use a presure tester on it yet.??? Sometimes you just have to get on top of the motor to see ..The miror is a good idea...Lew

 

I am currently going through a similar issue of what appeared to be water leaking from the head, but I found my leak between the timing cover and the block. Make sure you know where your leak is because it take some work to get that all apart.

Also, some of those bolts in the water pump can become frozen in the aluminum pieces to the point that you snap them off. Good luck!

 

Guys,

As it turns out, there is a heater inlet tube that mounts on a fitting that screws into the intake. This presses onto the fitting (I found out) and the seal consist of 3 o-rings (no threads or anything else). I realized when I took a closer look at the top of the intake that the water was indeed flowing from the front of the intake (right behind the thermostat housing) all the way out the back.


I am still not sure whether the leak was coming from the fitting screwing into the intake or the 3 o-rings on the inlet tube but when I dis-assembled the fitting applied teflon tape to the threads and replaced the o-rings it solved the problem.

Needless to say, I am quite pleased to have my Bronco back on the road.

Thanks for the advice everyone.