Originally Posted by ruxpin22
Hi I have a 98 F 150 Have had it at the dealer for a rad flush also had a new rad put in and a new water pump as well as replaced the thermostat twice. Also replaced the cap
The truck when you start it up cold and drive about 2 - 3 km the temp guage spikes and fluid spray's out the cap, I sut it off for about 10 sec and restart and everything is fine. It seems when it pressureizes before the thermostat opens it blows out the rad cap. with having the thermostat changed twice it still does it. There is no coolant in the oil nor coming out of the tail pipe so I know the block is not cracked. Checked the heater core and all is fine there.
I am at my wits end on what to do is there a simple way to reverse flush the system as the only thing I am thinking is wrong is that maybe a port inside the engine is clogged as when I go to drain the rad I only get about 2 litres of fluid from the rad. I have replaced just about everything and still overheats and blows at the cap the overflow bottle is the rad cap as there is no other cap for the rad. Only does this when cold and once shut off for 10 seconds and restarted is fine and can run all day until it is cold again. It has all the symtoms of a bad thermostat but I have replaced this twice already and the thermostat has been checked for opening temp. is there a way of reverse flushing as this would be the only thing left to do that I know of
Can anyone help. winter is almost here and I am sure if it keeps this up I might end up with a cracked block and dont need the expense of that.
Sounds like there is an air pocket in your cooling system. Also make sure the thermostat has a air release porpet in it. The air release porpet looks like a little giggle pin in the outer edge of the t-stat itself. If I were working on this vehicle and had to re-fill the rad I would use a vacuum refill procedure(we use a special "OTC" tool for this) to refill the rad and engine with fluid, This will ensure that all air pockets have been removed from the cooling system, (it can be a real problem getting the air out of a 'Fords' cooling system without this tool). A call to several local garages will help you find out if they have a vacuum refill tool. Hope this helps