I have a 96 Mustang GT 4.6. It has a new intake, fan, water pump, thermostat and thermostat housing. Here is the wierd thing if I drive careful with little of the heavy foot it runs fine. But if I take a long trip or hot rod it, when I shut off the car it boils over and kicks water out of the radiator but the digital thermoter reads 180 going into the motor and 200 coming out. So when I shut it off it acts like it is over heating but never runs hot even on the guages. Please help I have spent alot trying to figure it out.

 

I don't really understand the question...

 

My car is spewing hot radiator fluid into the over flow. I replaced the Water pump, Fan, Intake, Thermostat, and Thermostat housing. It only spews when I shut it off but all guages read the motor is not hot. Why am I spewing hot fluids from a car that is not over heating.

 

Is it spewing out of the actual over flow container? If so did you fill it with coolant to the cold line when the engine was cold or did you just fill it up. Coolant like any other fluid expands when it gets hot and needs to go somewhere once it expands. Dumping into the overflow is completly normal. Make sure you did not over fill the over flow. If all gauges read good and your gauges are not broken you shouldn't have a problem.

 

The mechanic shop did it they are stumped so I just got the car back tired of dumping money into it. Figured I would try the brains of all yall. I do not believe they over filled it

 

maybe the coolant mixture is not correctmust be 50/50

 

All sounds good ideas. I will try all of them but does anyone have any more ideas

 

I once hade a vehicle that did that and it ended up being a line that was narrowed because of gunk. It was a return lineso the coolant temps read good but it was getting hot because there wasn't a sufucient flow. The mechanic shop should have pressure tested it. Maybe flushing the lines would help?

 

also could be a bad radiator cap not holding pressure.
because water's boiling point is aprox. 212 degree's at sealevel. And if the cap is bad and not able to hold pressure in the cooling system the car will overflow the boiling coolant. the radiator cap holds pressure in the system ,andeach pound of pressure increases the boiling point.

 

A pressure test would tell all of that