Good evening, folks.

Finally decided to do a coolant flush after finding what looked like slightly oily brown sludge in the expansion tank (degas tank?), plus a New England winter is coming.
I've owned the truck for 12 years (2nd or 3rd owner) and have driven 40k or so in that time. She gets oil changes etc and has never given me a wink of trouble.
So, I ran her up to warm with a local drive around, and then drained it via the petcock. Then I ran the garden hose through it for a while and it almost ran clear. I filled it with plain water and went for a drive. Came back and drained it again, still murky, but better. Temp. gauge is fine, cabin heat works fine. But..... strikes me as odd that even after running for almost an hour, the bottom radiator hose is cold. The top hose from the thermostat is hot, and the hose to the cabin heater is hot, so the 'stat is probably working.

Am I overthinking it? Is this just normal? I'm reluctant to refill with new coolant if there is actually a problem that I should address first (partially blocked radiator, heater core, that sort of thing). Or maybe a big pocket of old coolant that is stuck in there somewhere.

Any advice would be greatfully received.

Thank you.

2001 Super Duty 5.4l gas, totally stock.

 

Did you flush from the heater hose with the lower radiator hose removed?

 

Nope, just from the expansion tank to the petcock, but that just made me realise that I was only flushing straight through the radiator. Except that after that I ran it for ages with plain water in there and it still didn't get hot down below.

 

So maybe I should be asking about the best method to use for a complete engine flush, rather than what I appear to have done so far? 😎

 

Best method is to pull the heater hose and remove the lower radiator hose. Flush through the heater hose and flush from the manifold nipple. You can also pull the upper hose and flush the radiator. Suggest replacing the thermostat also with a genuine motorcraft part.

 

Thank you. Would you use a flushing additive or just go with plain water? I have some, but if I don't need it then I won't use it. I suspect that the engine flush is LONG overdue.

 

The only flush I use and recommend is the heavy duty engine flush from Ford. Don't bother with the parts store stuff. Is there any rust in the system?

 

Fair enough. Rust in the system, probably. I have done basic maintenance since she came to me, oil, air filter, plugs, fuel filter, plus consumables like ball joints and exhaust systems.

I'm going to attack it again tomorrow using your advice, and will no doubt have a cleaner system 😁

 

BG makes an excellent coolant flush that I've used in multiple cars. Can't find it in parts stores, they only sell direct to garages, but you can find it on amazon/ebay too usually. Truck that old, I'd use it.

 

Do a search for Gooch's radiator method. Actually, I found it here:

https://www.powerstrokenation.com/fo...procedure.html

Great procedures and knowledge on which coolant you need, and other recommended things to replace on there. My F350 has over 215K miles and I replaced the thermostat, thermostat housing, water pump and ALL hoses for peace of mind. Take your time to read all of Gooch's method TWICE before proceeding or purchasing anything. I probably should have replaced my fan clutch while I was in there... Advance auto had the fan clutch tool you can rent for free which worked great for me. Good luck!

 

unsure why I can't delete my post when I accidently posted on the wrong page.