radiator bubbles?

66StangGuy · 06-05-2002, 03:07 AM

ever since i got my mustang iv had this problem. i will fill the radiator with proper coolant and everything. runs cool and no problems but when i turn the motor off i get foam out of the overflow tube. i was told this was because my hose clamps werent tight and letter air in and making bubbles. tried making sure they were all tight but still bubles. if i run my radiator with just water i have no problems. i know its not just extra excaping because it will continue to do that untill half of my coolant is gone. this only happens when i turn the car off. i also have a new rad. cap thats a 13 pound. iv ben told to go to a 16 pound but it will still foam. any ideas?

PKRWUD · 06-05-2002, 05:27 AM

Two points to understand here:

First, coolant retains heat, and raises the boiling temp of the fluid. Loosely translated, that means the fluid will be hotter, but will resist boiling.

Second, In order for the cooling system to avoid boiling over, it must be sealed. Loose hose clamps are a possibility, but a weak cap is more like it. The lower the pressure rating of the cap, the sooner the fluid will overflow.

Now, since the coolant allows the fluid temp to be higher, more pressure is created. With more pressure, you need a higher rated pressure cap. I would go too a 16 or 17 pound STANT LeverVent cap, and make sure you don't have more than 20% coolant (w/ 80% water) in the system.

Take care,
-Chris

66StangGuy · 06-05-2002, 11:07 PM

ok those are good points. but my problem is the coolant foaming up not coolant leaking out. maybe i didnt explain this enough. its not actually liquid its just foam. also any reason why this only happens after i turn the engine off?

PKRWUD · 06-06-2002, 07:27 PM

Okay. I still think you should replace the cap, but you should also run a compression check. Foaming is often a sign of a head gasket failure or a crack.

Take care,
-Chris

06-05-2002, 03:07 AM	#1
66StangGuy Registered Member Join Date: Feb 2002 Location: Diamond Bar Posts: 258	radiator bubbles? ever since i got my mustang iv had this problem. i will fill the radiator with proper coolant and everything. runs cool and no problems but when i turn the motor off i get foam out of the overflow tube. i was told this was because my hose clamps werent tight and letter air in and making bubbles. tried making sure they were all tight but still bubles. if i run my radiator with just water i have no problems. i know its not just extra excaping because it will continue to do that untill half of my coolant is gone. this only happens when i turn the car off. i also have a new rad. cap thats a 13 pound. iv ben told to go to a 16 pound but it will still foam. any ideas? __________________ 66 mustang-292-Holley 4160-World Castings Windsor Sr.-Hooker super comp headers-MSD box & Coil.3.55 gears. B&M Z-Gate-Black leather racing seats with 4pt harnes.

06-05-2002, 05:27 AM	#2
PKRWUD Junior Member Join Date: Mar 1999 Location: Ventura, California Posts: 8,981	Two points to understand here: First, coolant retains heat, and raises the boiling temp of the fluid. Loosely translated, that means the fluid will be hotter, but will resist boiling. Second, In order for the cooling system to avoid boiling over, it must be sealed. Loose hose clamps are a possibility, but a weak cap is more like it. The lower the pressure rating of the cap, the sooner the fluid will overflow. Now, since the coolant allows the fluid temp to be higher, more pressure is created. With more pressure, you need a higher rated pressure cap. I would go too a 16 or 17 pound STANT LeverVent cap, and make sure you don't have more than 20% coolant (w/ 80% water) in the system. Take care, -Chris __________________ Webmaster: Rice Haters Club Jim Porter Racing Peckerwoods Pit Stop Support Your Local RED & WHITE!

06-05-2002, 11:07 PM	#3
66StangGuy Registered Member Join Date: Feb 2002 Location: Diamond Bar Posts: 258	ok those are good points. but my problem is the coolant foaming up not coolant leaking out. maybe i didnt explain this enough. its not actually liquid its just foam. also any reason why this only happens after i turn the engine off? __________________ 66 mustang-292-Holley 4160-World Castings Windsor Sr.-Hooker super comp headers-MSD box & Coil.3.55 gears. B&M Z-Gate-Black leather racing seats with 4pt harnes.

06-06-2002, 07:27 PM	#4
PKRWUD Junior Member Join Date: Mar 1999 Location: Ventura, California Posts: 8,981	Okay. I still think you should replace the cap, but you should also run a compression check. Foaming is often a sign of a head gasket failure or a crack. Take care, -Chris __________________ Webmaster: Rice Haters Club Jim Porter Racing Peckerwoods Pit Stop Support Your Local RED & WHITE!