over heating

[silleluap]

hi everyone my name is Paul new here I have a 99 xlt 4x4 3.0 v6 flex and a question about it over heating . my truck is blowing the top off the overflow bottle and not drawing it back. the hoses are clear new instaled a new cap and throstat did a pressure check hold 12 lbs 2.0 hrs. no leaks no sign of water in exhust pressure check on cyl. was good and water pump is good?. at a loss any ideas?
any help will be good thanks

 

[joecrna]

Does it actually over heat and then blow the cap off the overflow bottle or does the cap blow off without overheating? The only time mine has blown the top off the overflow tank, my water pump was not working. Though it did draw all of the fluid back to the radiator when it cooled.

 

[silleluap]

no it has never fully overheated when it got high on the gage I shut it down and added water but temp climbed real fast

 

[Rosscup]

if it is just gargling in the resivore then its a head gasket if you really want to make sure that it is a head gasket get a block test done that will show you if you are getting a exhaust gases in the cooling system. ussaly the first thing that goes when you over heat is the head gasket.

 

[MustangP51]

Also check for antifreeze in the oil.

 

[silleluap]

missed the block check will be next step
ya forgot to say that oil was clear also thanks much

 

[silleluap]

Thanks again for the help turns out it is a block leak , droping a rebuilt next week end