I have a 2008 with a 4.2 in it. I’m not having any issues with the cooling system. However the truck had been basically sitting still for about 5 years. They did start it a few times a year during that time. I’ve worked on it to make it drivable and have been using it for a few months now.
My question is, should I just leave the cooling system alone or give it a flush and fill? I don’t want to open up a can of worms if it’s not necessary.
Thanks.

 

Depending on the mileage that is on it you might want to just do a drain & refill.

 

search youtube for: fordtechmakeuloco coolant diy flush


if you are due for a water pump, it makes sense to do the flush as he describes, but install pump/pulley/tensioner belt, before filling back with fresh coolant.

 

.

Definitely would change after 5 years to better protect the radiator, water pump and head. Not that expensive for the peace of mind.

 

FWIW
If you are going to do a fill and drain with multiple fill and drains or continuous fill/drain you need to be aware about 50% of the final flush water will remain in the cooling system. This means the water used for the final couple of flushes needs to be distilled water. You need to know the system volume and for a 4.6 it is right around 20 qts but you need to confirm this before you drain for the final time. Why do you need to know the system volume? Because to end up with a 50% mixture you need to drain out at least 50% of the system volume so that you can put the proper amount of 100% coolant into your system to bring the total system concentration to 50/50. In my case I drained 9 qts (I did not drain the lower radiator hose but you should) and my system volume was 20.6 quarts giving me a 43% mixture so not a freezing problem for me in Mississippi but I will continue to top off with 100% as level permits to provide additional corrosion protection.
OK it's time to drain in preparation for the new 50/50 mix. Put your empty drain container in place and drain the distilled water until it stops draining and measure the amount you drained and if necessary, drain the lower radiator hose to ensure you empty out enough to provide room for the 100% coolant you are going to be adding. If possible, I would avoid removing engine block drain plugs since in my opinion you may create more problems than it's worth. Things break.
Mine is a 2007 F150 4.6L 2v 4x4, 20.6 quarts

 

I would only do a drain and refill too
Unless you get a bunch of rusty coolant out of it
Enjoy that 4.2

 

Thank you all for the replies and advice. The truck only has 77,000 miles on it. I was planning on having a shop do a flush and fill, but now I think I will do just a drain and refill on my own.

 

did you watch fordtechmakeulocos video?

 

No, not yet but I will. I’ve seen his videos before on YouTube. Good stuff.