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Cat Man
Cat Man, Cat Engine Expert
Category: Medium and Heavy Trucks
Satisfied Customers: 8916
Experience:  I am ASE Master Truck Certified.
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Ford f650: 04 ford f650 with cat c7 acert (kal13079) cooling

Customer Question

04 ford f650 with cat c7 acert (kal13079) cooling system over pressure as soon as its started slowly goes to 30 psi +,we bypassed the air compressor to rule that out! installed new thermostats then removed them,same result, flushed system multiple times. when running hot i noticed even tho the system is over pressurized, the top hose that connects to the radiator is soft and empty and this is with no thermostats,what could the problem be before jumping in to engine rebuilding or replacing major engine components? (fyi 4th water pump and it changes color just like an exhaust manifold does)
Submitted: 1 year ago.
Category: Medium and Heavy Trucks
Customer: replied 1 year ago.
Also just removed the belt to see if water pump causing the problem. System still over pressurizing immediately.
Expert:  Jeremy replied 1 year ago.
My name is ***** ***** I will assist you with your question today. I'm an independent contractor and I don't get paid until a rating has been made. We can go back and forth as needed to help resolve the issue you are having. Follow ups are free after ratings, so rate in confidence! If the system is building pressure that fast, you have either a injector cup leak issue or you have a head gasket issue. Pull the valve cover, then the injectors and pressurize the cooling system. See if you can see any leaking around the cups. If not, head gasket is the most likely cause. I state this becasue you ruled out the air compressor and water pump. With the pump getting hot and looking like a exhaust manifold that you have a lot of pressure in there and are getting hot from the engine compression.__________________________________________________________________________________________________________________________You want a 5 star service and I want to provide a 5 star service. Please consider that I don't know your skill level as well as I can't see, touch, smell, hear the vehicle/machine in question. Please provide as much detail as possible and I will provide as much back. Once an answer is provided, you should see a rating screen. Please rate my personal service to you. The ratings are my personal feedback,they are not the site feedback. Thank you for allowing me to assist you through Just Answer! Jeremy
Expert:  Jeremy replied 1 year ago.
I see you viewed this and this is still showing as a open question due to no positive (3 stars or more) rating.Did you still need assistance with this?
Customer: replied 1 year ago.
yes, we took the compressor off completely and we are seeing the same problem. In addition to that, we using the diesel block tester to see if the pressure is exhaust coming through the cooling system. It didn't change colors, so where would the pressure be coming from if the compressor is off and according to the block tester test, its not exhaust gases????
Expert:  Jeremy replied 1 year ago.
I'm going to opt out and see if Catman can take over. I am out of town doing training and don't want you waiting.
Expert:  Cat Man replied 1 year ago.
Thanks for asking your question. I will try and help you out.
If the air compressor has been bypassed. All that is left is a blown head gasket, cracked head , or cracked block. Cracked blocks are rare but since the engine has no liners. It's possible. I have seen it a few times.
I know you used an exhaust gas tester but to be honest. I have seen them not be accurate when diagnosing high coolant pressure and head gasket failures. Actually with the air compressor not the problem. There's really nothing else to cause this high of pressure.
Please reply back if you need more help or have more questions. I am happy to assist.
Expert:  Cat Man replied 1 year ago.
Hey. I just wanted to see how things were going. Please let me know if you need more help. I am happy to assist. If my information was helpful, please leave a good or higher rating so that I receive credit. Thanks.