1996 Dodge Avenger Sprays antifreeze out of overflow tank cap?

Question

I drove my 1996 Dodge Avenger ES 6 Cylinder Automatic about 25 miles and then shut it off. I popped the hood and to my surprise it was spraying antifreeze out of the overflow tank cap... i just bought this avenger and the previous owner had blocked the drain hose coming out of the overflow tank. when i started driving the avenger the antifreeze level was within the low and high level on the tank.

when i stopped the tank was spewing out antifreeze out of the overflow cap and the tank was full of antifreeze. but after about 1 or 2 minutes the pressure lowered and the level of antifreeze dropped to under the low line on the overflow tank.

i watched the temp and the oil pressure the whole time i was driving the car and both gauges stayed at the mid level. The temp never passed about mid level. There is no antifreeze in the oil and it does not smoke. the engine has never skipped a beat the whole 330 miles i have driven it

Could this be the pressure cap not using enough pressure to keep the antifreeze in the radiator? It is a 6Lb cap.

thanks for the help

Answer 1

I'm not sure, but a 6lb cap seems to low a pressure. try and replace cap with an OEM rated one. if that doesn't work then you may have some internal engine issues.. such as head gasket or cracked head- compression leaking into cooling system. But that should cause an overheat issue too. Good luck

Answer 2

hi

you need to check your head gasket because coolant systeme use like 7to12 pounds of air pressure but if the head gasket is not ok could be engine air compression mix with coolant systeme and create over 80 or 90lb of air compression. it may be  the reason.

Answer 3

the best place to start is at auto zone.... the website doesnt say... but id say try that first

Answer 4

you should be running at least a 16 pound pressure cap on that one,most run about 17 pounds and then release it in to the reservoir,id try a new cap,and may be ask the old owner why they had the return line blocked off,that's a sign of pressure building up on it,which isn't good,this means they have been having problems from it also,if it continues to do this you might want to consider having a pressure check ran on the cooling system,good luck.

Answer 5

Most cars run a 17lb cap from factory.  It sounds like there is too much pressure building up for some reason.  Most cases this is a head gasket.  Just because there is no anti-freeze in the oil, does not mean that there isn't a head gasket or cracked head issue.  I would take the car to a competent garage and have them run a cylinder compression test on it.  This will tell you if you have a head issue.  From there once you pull the head to check the gasket, you can check the head also.  Good Luck.