4.6 overheating

[global2957]

Hey guys this ones got me baffled please help. my 96 Lincoln 4.6 V8 needed two oxygen exhaust sensors, changed them then the car started to overheat when changing coolant. bled the air out seemed to run fine took it for a drive and the heat went thru the roof. let it cool down got more air out of it and seemed to be fine. let I run several times for an hour or so no problem, took it to the store short trips again no problem. the other day we took it on the highway at 60mph heat shot up thru the roof. waterpump ? I am totally lost. please some input would be appreciated thanks in advance Ralph

 

[MooJohn]

I'd have the radiator checked for clogs. If the radiator hoses are old they could be collapsing under the load.

I hate to mention it but you may also want to rent a head gasket leak detector kit. Stores like AutoZone will loan you the tool and you buy the chemicals needed to do the test. There are youtube videos that show how to do it but basically you drive the car some, park, and use this syringe to pull air from the overflow tank through the chemical (just air, no coolant). If it changes color it means there's a headgasket leak that is causing the overheating.

http://www.autozone.com/loan-a-tools/block-tester

 

[bradyelich]

Make sure the coolant is filled thru the round port in the 'H' pipe not the overflow tank. The warnings are there but nobody regards them.