What's the best way to flush out the block? This is on a 300 straight 6. I'm in the middle of swapping out the front clip, so the radiator is gone. I've got all the hoses off and t-stat out. I was thinking I'd just stick the garden house into where the t-stat was and cover the opening with a rag, turn the hose on, and then let it come out the other end of the water pump. Will that work?

 

That will work as well as anything. That is what the radiator shops recommend here. jd

 

Bring it to a shop like mine..we use Wynn's Coolant System Flush Machines. It does wonders and you should see some of the coolant/gunk that comes out sometimes.

Ask the shop what they use, Wynn is the BEST on the market in my opinion. We've used a couple different brands and they were the best.

 

Running a garden hose through just the block is stupid because then you don't flush out the heater core or Rad which will contaminate your new Minty coolant

I've heard of people using a little bit of dishwasher detergent into a straight water mix with everything running for 5 or 10 mins, then drain and refill with good stuff.

I've heard of...something else I can't remember too well, Lye? Lime? Lemon? run through while it is running, then drain and replcae with good stuff.

I just take mine to the local crappy tire(CanTire for you Staters or elsewheres)every year or two.

I think it would be better to run it through ANY flushing machine at a shop of your choosing because it will be running through at a higher pressure than your garden hose, and flush the Rad, the Block, and Heater core, and all the lines as well. AND you don't have to worry about what to do with the old coolant.

I swapped an engine from a Granada into an F150 and re-used the coolant after straining it back into the truck rad so I could drive it to the shop so they could flush it and recycle it for me so I wouldn't have to worry about the pets lapping it off the ground and dying, it is poison to them you know. But I ended up driving the truck for a couple months first, good thing it was summer, the old coolant was ten years old!

 

The reason I am asking about the block is because every other component of the cooling system is out of the truck and being taken care of separately. The truck is in the garage without a front clip at the moment (hopefully now that the weekend is here I have time to change that) I am flushing the heater core on its own. As for the radiator, I have to look through it a couple more times but I'm not sure if I'm keeping it. It is 30 years old and has been repaired close to a dozen times, and not all of the repair spots look very good (crustiness, discoloration, etc).

The shop machines sound like an interesting idea, but like I said the truck is in the garage without a front end. I'm just going to stick with the hose. Anyway, thanks for the advice guys!

 

> What's the best way to flush out the block?

You need to build pressure, what you can do is go to Home Depot and get a sewer flushing balloon. Basically a rubber bag on the end of a hose, you stick it into a hole, the water pressure makes the sides expand, then the rest of the water is forced out of the 1/4" hole at the end.

Much better then a rag covered hole.

 

That's pretty much how I do one if the coolant isn't real bad. Disconnect or remove radiator and do it separate. Unhook heater hoses and flush each way through them. Then flush the block through the thermostat opening and some through each heater hose connection. If the block drains are easy to get to I pull them out and flush too.