Need some help!

archerman0531

Registered User
Ok, I know this isn't a mustang forum, and I'm not a member of one.

My wife has a 1994 mustang with the 3.8in it. It started pushing coolant out into the over flow and running the radiator dry. After about a month of doing this I finally got tired of it and started lookin into it. The antifreeze smelled like exhaust gas. So, I knew I had to do a set if head gaskets in it.
I had the heads machined, used fel-pro head gaskets, brand new head bolts. Everything was torqued to factory specs.

My problem is, it's still pushing coolant into the overflow an not sucking it back in. I can't figure out why. It has brand new thermostat, the radiator cap is new(15-16psi, checked it with a cap tester). Correct mixture of coolant to water, water pump seems to be workin fine, new radiator.

Needing some help with this please!
Thanks!
 
You either still have a leak somewhere, or the radiator cap is bad.

I'd do the cap first (why, yes, they CAN be bad out of box. If stuff never was, why would anything have a warranty?) and then batten down and see if I could find the coolant leak (and it could be leaking INTO the coolant only, not OUT)

RwP
 
Thanks for the reply. I actually checked the cap with a cap pressure checker pump tool thing(whatever it's really called). I forgot to add in the order post. The whole cooling system will hold 16psi for over 2 hours without leaking as well. I'm just at a loss at this. And really getting tired of messing with it.
 
- Use a straight 16# cap - new. No lever-cp or something that claims a range from something to 16#.

- Be sure the hose to the overflow tank isn't plugged.

- Be sure the airflow thru the radiator isn't plugged and the radiator isn't junked up inside.

- If that engine has one, consider replacing the ECT sensor. Check the codes to see if there are any hints concerning engine management/cooling. Electric fan?

- Check the water pump to see if it is leaking under the snout. If it's old, it might be sucking air and/or have a worn impeller.

- Were the heads crack checked? Did that job show a clear gasket etc. failure? Was the car blowing steam out the exhaust? Did you add any kind of stop leak when putting it all back together?

At least on the Super Coupe's, it can take a while (few hundred miles?) to get all the air out of the cooling system and for the draw back from the overflow tank to stabilize, etc. You might want to add WaterWetter for that extra bit of help.
 
- Use a straight 16# cap - new. No lever-cp or something that claims a range from something to 16#.

- Be sure the hose to the overflow tank isn't plugged.

- Be sure the airflow thru the radiator isn't plugged and the radiator isn't junked up inside.

- If that engine has one, consider replacing the ECT sensor. Check the codes to see if there are any hints concerning engine management/cooling. Electric fan?

- Check the water pump to see if it is leaking under the snout. If it's old, it might be sucking air and/or have a worn impeller.

- Were the heads crack checked? Did that job show a clear gasket etc. failure? Was the car blowing steam out the exhaust? Did you add any kind of stop leak when putting it all back together?

At least on the Super Coupe's, it can take a while (few hundred miles?) to get all the air out of the cooling system and for the draw back from the overflow tank to stabilize, etc. You might want to add WaterWetter for that extra bit of help.

I do have a pressure checked 16psi cap(actually pops at 17-18). No lever.

Overflow tube is not plugged. Cleaned it out.

Radiator is brand new and has less than 300miles on it

It has a brand new ECT sensor(checked resistance they pins at different temps and shows its within range

Electric fan kicks on and does have both fan speeds.

Water pump appears to be good. No leaking from weep hole and it circulates, but I was thinking that it might be worn and not working correctly.

Both heads were milled and pressure checked. One head had a VERY slight crack on the outer water jacket that just ended into the casting. It was not making its way off towards the combustion chamber or anything like that. The guy I had do the work has done machining for 40+ years and didnt seem worried about that. He said he has put on heads with worse cracks and haven't had a problem with them. And he does alot of 3.8 heads.
Car was NOT blowing steam. But there was clear evidence of a bad head gasket.
No stop leak was added.


I will try the water wetter.

Thanks for the reply!
 
And once you close it up, sit on your hands - let it continue to heat cycle without removing the cap, cracking the bleeder over & over, etc...be patient while all the air is bled out - don't let the overflow tank run dry. I think you'll be fine.
 
Back
Top