Ok I am putting a new block heater on my truck and want to flush the cooling system befor I put it on. Would you guys use any cleaners or just water?

 

Water

 

50% white vinegar (5% acidity)/50% distilled water, followed by a second flush with straight distilled. I never use commercial flushing products -- the last classic I owned still had the 30 year old factory-installed radiator in place when I sold it. Maybe I did something right, maybe I've just been on a lucky streak. But it works fine for me.

 

How long would you run the white vinegar / water mix?

 

vinegar? never heard of that.

anyway - be sure and remove the block drain plugs. they hide on each side next to the engine mounts. little hex head plugs that are probably tighter than hell. also difficult to get a socket on. use a 6 point socket or good vice grips to prevent round off. when reinstalling use teflon tape or liquid or antiseize or something. also don't overtorque when installing, its just a plug.

 

To operating temp plus five minutes or so, just idling in place. Same for the second (DW) flush.

What I usually do is drain the flush before it's fully cold, not so soon that residual heat in the block or getting scalded might be a problem, then let the block cool (to prevent stress cracks) before starting the second flush. During the DW flush, I usually run it with the radiator cap off and watch for floaties in the radiator, and if I see too many I'll repeat the whole process. It's a good lazy Saturday afternoon kind of project.

If I strongly suspect that the system is gunked up, I'll let it get completely cool after draining the 50/50 flush, remove the thermostat and lower radiator hose, stuff a garden hose with a rag wrapped around it into the reattached water neck, and flush the bejeezus out of it with a few short (30 second or so) runs of the engine to get the water pump moving around a bit. Then the water hose goes into the radiator, but not cranked way the heck up, and that gets run until the water is clear for a good while. Then I'll follow that up with the straight DW flush after putting it all back together, then fill and burp the coolant.

 

Well I am going to replace the top and bottom rad hose and all the heater hose so I will use the water hose to clean the rad out.

 

Bump!

 

Well I drained the cooling system today I got both drain plugs out. I was not to bad getting them out but I have been spraying blaster on them for the last month. I refilled with water and ran that for 10 or 20 min and drained that flushed the heater core out and flushed the rad and block good and left all the plugs open till tomorrow.
Also which heater hose is the heater core inlet the one on the pass side or the one coming from the driver side

 

The one on the passenger side. The one with the coupling in it.