Questions about radiator flush 94 Ford Ranger

[Jason30]

Hey all. New to the forum. Any advice or help you all can give me will be very appreciated. I'm not very repair savvy and have some questions about flushing the radiator. It's been sitting for a while and inside the radiator is full of sludge and rust. At first I thought the head gasket was blown or cracked so I picked up the chemical test block but the test passed.

First question, is the attached picture the petcock valve? And if so how exactly should I flush the radiator. I've been reading a lot and want to be very thorough so I don't mess anything up.

Should the steps go....Turn on car, turn on heater until it heats up then turn off, open radiator cap, open peacock, let drain fully (or do I leave car and heat on while it's draining?) Then turn car back on, turn heater on, put in coolant flush fluid with water, open radiator cap, turn petcock, let it drain...then fill back up with 50/50 while car is running with heater on?

I'm just a bit confused as to when the car and heater should be on during the flush. If anyone has a step by step in detail that would be great! Thanks for reading and I look forward to being an active member now that I'm a Ranger owner!

 

[adsm08]

Well you certainly don't want the engine running for any period of time without coolant in it.

All proper flushes consist of two parts, the running of a solvent to break up and free deposits from the system, and a fluid exchange to remove said deposits. The best type of exchange is when the new fluid is used to push the old out of the system.

The best way to go about it at home without real equipment meant for coolant exchange is to drain a bit, maybe half a gallon or so, replace it with CLR and then run the engine until it gets good and hot, then let it run for a little while longer. If things are really bad it wouldn't hurt to just drive it for a day or two with the CLR in there.

Once you have run your solvent (the CLR) drain the coolant from the radiator, pull the heater hoses off at the water pump, and remove the radiator and thermostat, reinstall the thermostat housing. Run a garden hose through the heater hoses, switching direction of flow, until both directions run clear, then blow through one of the hoses to remove the water. Run more water through the upper rad hose until the stuff coming out the bottom hose runs clear. You can try blowing on the rad hoses to remove water, I doubt you will have much luck unless you have impressive lung capacity. Then do the same thing with the radiator, prop it up against a wall and run the hose through it until it starts running clear. Turn it over and repeat. Dump as much of the water out as you can.

That is the "flush" part.

After all that is done I would throw a new thermostat in it, they are only $5-10, but you can reuse the old one if you like, just put a new gasket on it, hook up your heater hoses, put the radiator back in, and add one gallon of quality (reads "Not Peak") concentrated coolant, because you probably have a good bit of water still in the system. Then begin adding 50/50 mix to the radiator until it is full. Next remove on of the heater hoses at the heater core (the opposite end from where you took them off the last time) and pour your 50/50 mix in the hose until stuff starts coming out of the heater core. Reconnect the hose, make sure all your connections are tight, and start it up. Take it for a spin around the block, 4 or 5 miles, check and top-off the coolant, being very careful when removing the cap as you can easily be burned at this point.

This would also be a good time to install a new radiator cap since they are also cheap insurance.

Do your best to catch as much of that coolant and water as you can and have it disposed of properly. The ethylene-glycol in engine coolant is a powerful neuro-toxin and can go quite a bit of damage if allowed to get into the water table.

And yes, your picture does show the radiator drain cock. Open it up and THEN remove the rad cap. It will make less of a mess.