Coolant flush

[JTMiller13]

Hey guys,
I was hoping someone could tell me the approx amount of coolant I will need to do a full rad/block/system flush on my 92 silverado 454?

 

[k1500 97]

Hey guys,
I was hoping someone could tell me the approx amount of coolant I will need to do a full rad/block/system flush on my 92 silverado 454

Are you planning on doing the flush your self, cuz I do believe you flush it with water at a very low psi, or you asking how much to refill it after the flush?

 

[JTMiller13]

Yes, I'm doing the flush myself, flushing with water, I'm just looking to know how much coolant I will need when I refill it following the flush

 

[k1500 97]

Yes, I'm doing the flush myself, flushing with water, I'm just looking to know how much coolant I will need when I refill it following the flush

About 4 to 5 gallons depending on what radiator you got, but that definitely should be enough for ya, my dad's 95 454 took little over 4 gallons, some one may be more helpful but thought I'd pop in

 

[JTMiller13]

About 4 to 5 gallons depending on what radiator you got, but that definitely should be enough for ya, my dad's 95 454 took little over 4 gallons, some one may be more helpful but thought I'd pop in

Thank you. I appreciate it

 

[Schurkey]

Look in your owner's manual. Cooling system capacity will be listed for your engine/accessories.

Use 1/2 of capacity for minimum anti-freeze quantity. Depending on where you are, more can be better. Put the anti-freeze in first, before you add the distilled water. (Save a little for the overflow bottle.)

PULL THE BLOCK DRAINS--one on each side of the engine--before and after the flush, to remove old coolant, and then remove the flush water. Some guys just pull the drains and leave 'em out during the flush. I replace the original iron/steel block drain plugs with brass draincocks. Makes it heaps easier next time. If this was a small-block, the knock sensor would be screwed into one of the block drain holes, so you'd have to put the knock sensor back in and torqued to spec, no draincock on that side.

I recommend a "Flush and Fill" kit from Prestone or other vendors.
www.amazon.com/Prestone-AF-KIT-Flush-Fill-Kit/dp/B000CCFY5W/ref=sr_1_2?crid=3LCIWSTDXCD2W&dib=eyJ2IjoiMSJ9.SSQ3xAOaJ7Qmif3O8eNs_DmM0ohSAhdFFpR4pRd8RJVEiYzPcf_x02wnIi4ZEfHFPxtfJN58Gfp6uXAxlaw2-Eqg5uAAeu0x4PjLYwr4wdm-0wJ9CHzVwFTgJT8ZBYx0H9imccMXJKmqTthabs2afg.DXmGO_mPtkBJC-FLe-lJJqgH-brcIgym5uW-rMga1rk&dib_tag=se

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[454cid]

I recommend a "Flush and Fill" kit from Prestone or other vendors.
www.amazon.com/Prestone-AF-KIT-Flush-Fill-Kit/dp/B000CCFY5W/ref=sr_1_2?crid=3LCIWSTDXCD2W&dib=eyJ2IjoiMSJ9.SSQ3xAOaJ7Qmif3O8eNs_DmM0ohSAhdFFpR4pRd8RJVEiYzPcf_x02wnIi4ZEfHFPxtfJN58Gfp6uXAxlaw2-Eqg5uAAeu0x4PjLYwr4wdm-0wJ9CHzVwFTgJT8ZBYx0H9imccMXJKmqTthabs2afg.DXmGO_mPtkBJC-FLe-lJJqgH-brcIgym5uW-rMga1rk&dib_tag=se

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If the heater core return line goes to the radiator, the flush kit doesn't really flush the block. I realized this when I tried using one on my truck. The T connects to the hose running to the heater core, and the return line connects directly under the filler neck that has the waste tube from the kit installed. The flushing water exits almost immediately and there would be very little flow through the block.

 

[Schurkey]

Put the tee in the hose between heater core and radiator tank. Clamp the heater hose on the radiator side of the fill kit with a needle-nose vice-grip or specialty hose clamping tool.

Engine off. Flush water from the tee back-flows through the heater core, into the engine at the intake manifold connection, and out through the open block drains--and into the radiator via the water pump passages and lower rad hose back-flushing the radiator (assuming the thermostat is closed.) Coolant can exit the radiator at the filler neck also, but put the cap back on to back-flush the radiator via the radiator drain..

Conversely, release the clamp, re-clamp on the heater core side of the flush tee. Rad cap off to start with. Let the water run until the rad fills up. Install cap, block overflow nipple. Start the engine. Flush water goes to the "cool" tank of the radiator, into the engine via the water pump, out the block drains, and out the upper radiator hose (thermostat open or--more likely--removed) to the "hot" tank of the rad, and then out the radiator draincock.

There is some risk of running the engine low on coolant, depending on how fast it's exiting the block drains, radiator drain, and radiator filler neck.

Directing flushwater flow is a game of providing deliberate restriction here and there, installing or removing drain plugs--or opening/closing draincocks. Use the engine's water pump (engine running) to boost circulation as desired.

I try to remove the overflow bottle, add some HOT water and a little bit of detergent, and some playground sand. Slosh the sand around to "scrub" the dreck off the inside of the bottle.

It's essential to remove block drain plugs (which might be the knock sensor on some engines) so that the old coolant is thoroughly drained, and the flush water is similarly drained.

Folks have cracked blocks in the winter or at high altitude (cold weather) because they failed to remove flush water, failing to account for the trapped flush water when re-filling the cooling system with "50/50" prediluted antifreeze. What they add might be "50/50" but there's already over a gallon of straight water still in the block further diluting the coolant.

Some engines (Lookin' at you, Buick) don't have block drains. So the flush water either gets partially drained with gymnastics of lifting the rear of the vehicle, or dicking with engine core plugs, or just leaving the flush water but adding the full measure of "pure" anti-freeze before final dilution with however much water it takes to completely fill the cooling system.