It seems to be that when you've opened the drain fitting at the bottom of the radiator, once the radiator has drained, the coolant in the block should then flow through the bottom radiator hose and into the bottom of the radiator and out of the radiator drain fitting. Am I wrong in this and if so why?
Does block drain through bottom of radiator?
- Thread starter jmacmaster
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Everything from the pump-down will come out the bottom hose, but there's still quite a bit left in the heads and heater core that has to be pushed out using the engine's water pump. If you're looking for a complete flush, simply remove the top radiator hose and point it in a safe direction...then take the cap off the radiator and fill it with fresh water and keep the garden hose handy.
Turn on the engine and wait for the thermostat to open..at which time hot coolant starts flowing out the top hose. Use the garden hose to keep the radiator full while the engine is running, until the water coming out the top hose runs clear. Next, start pouring in the new 50/50 mix until you see it start coming out the top hose. Have someone shut off the engine. Top off the radiator, reattach the top hose, and put the cap on. Fill the reservior with 50/50 and start the engine again, keeping your eye on the reservior. Keep it filled until the engine stops taking from it.
This is a method used to prevent air bubbles from getting trapped in the heads. Older GM 3.1 V6s and some Dodge V8s have valves in the intake manifold to help bleed air from the top of the engine...other engines don't have these, so any air you pumped in remains there, possibly causing hot spots in the heads which can warp them, leading to head gasket failures, etc.
Hope this helps.
Turn on the engine and wait for the thermostat to open..at which time hot coolant starts flowing out the top hose. Use the garden hose to keep the radiator full while the engine is running, until the water coming out the top hose runs clear. Next, start pouring in the new 50/50 mix until you see it start coming out the top hose. Have someone shut off the engine. Top off the radiator, reattach the top hose, and put the cap on. Fill the reservior with 50/50 and start the engine again, keeping your eye on the reservior. Keep it filled until the engine stops taking from it.
This is a method used to prevent air bubbles from getting trapped in the heads. Older GM 3.1 V6s and some Dodge V8s have valves in the intake manifold to help bleed air from the top of the engine...other engines don't have these, so any air you pumped in remains there, possibly causing hot spots in the heads which can warp them, leading to head gasket failures, etc.
Hope this helps.
JHZR2
Staff member
I never had luck draining out of the radiator. Heck, I never had luck running the vehicle and forcing the hose to flow through.
I think that removing the hoses is the only real way (maybe some purists would say to also remove the block drains)...
That said, for me, who enjoy doing DIY work, doing a full flush and clean isn't good for me - Im not sure enough of myself to do it - though ive done more, more advanced stuff.
So, what I do is maximize the condition of what is in there by draining and fglushinbgthe radiator yearly, then getting the coolant (long-life) replaced every 4 years or so.
JMH
I think that removing the hoses is the only real way (maybe some purists would say to also remove the block drains)...
That said, for me, who enjoy doing DIY work, doing a full flush and clean isn't good for me - Im not sure enough of myself to do it - though ive done more, more advanced stuff.
So, what I do is maximize the condition of what is in there by draining and fglushinbgthe radiator yearly, then getting the coolant (long-life) replaced every 4 years or so.
JMH
There is a huge risk of the block cracking with this procedure. I do the distilled water flush, as advocated by the guru of this forum, Ray H, and many others. There have been numerous discussions on this previously and a search will bring them up. I also remove the block drain(s), it is not a difficult thing to do on most engines when it is not hidden by the starter.
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