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Flushing the coolant

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Old Jan 2, 2012 | 06:52 PM
  #1  
Synyster's Avatar
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From: New England
Year: 2000
Model: Cherokee
Engine: 4.0L
Default Flushing the coolant

Plan on doing this shortly before the snow starts. Water Pump inlet hose is rusted so I think I am gunna need to take that off and replace the waterpump as well. How hard is it to remove the waterpump? Also want to make sure I get flushing the system steps correctly.

Plan to release the petcock underneath the radiator and let all of the fluid drain into my 5 gal bucket. Then remove the upper and lower hoses and replace with new ones. Also replace the thermostat. Once all that is done put the petcock back on and then pour some distilled water and radiator cleaner into the radiator via the radiator cap up top. Let the car run for 10-15 minutes with heat on high. Shut car off and allow it to slightly cool. Drain the water/cleaner out via petcock then put petcock back on. Add 50/50 mixture to radiator and overflow tank.
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Old Jan 3, 2012 | 02:14 AM
  #2  
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From: Indianapolis Indiana
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sounds like a plan
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Old Jan 3, 2012 | 06:08 AM
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Not sure where the petcock is on a 2000, it's kind of hidden on my 99. I don't use petcocks as they can break and then you've got bigger problems. I strictly use the lower hose to drain the coolant. I recommend you do the same.

Be sure to use a high quality thermostat. I buy mine exclusively from Jeep for the best reliability. Well worth a couple of extra bucks.

Definitely replace the water pump while you're digging in. New only; no rebuilt or remans here. Consider installing a new radiator too. If yours is original, you are on BORROWED time. Don't forget about your heater hoses too!!

Also know that if you fill the system up with distilled water and cleaner and then drain it, you will NOT be at a 50-50 concentration if you add just 50-50 mixture. Don't forget that you will still have quite a bit of plain distilled water in the engine. You will need a stronger final concentration of antifreeze to GET to a final 50-50 mixture. Be sure to verify with a hydrometer (available at any parts store) Use conventional (green) antifreeze.

Dollar for dollar, no better money spent than that spent on your cooling system.

Last edited by tjwalker; Jan 3, 2012 at 06:12 AM.
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Old Jan 3, 2012 | 07:19 AM
  #4  
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Originally Posted by tjwalker
Not sure where the petcock is on a 2000, it's kind of hidden on my 99. I don't use petcocks as they can break and then you've got bigger problems. I strictly use the lower hose to drain the coolant. I recommend you do the same.

Be sure to use a high quality thermostat. I buy mine exclusively from Jeep for the best reliability. Well worth a couple of extra bucks.

Definitely replace the water pump while you're digging in. New only; no rebuilt or remans here. Consider installing a new radiator too. If yours is original, you are on BORROWED time. Don't forget about your heater hoses too!!

Also know that if you fill the system up with distilled water and cleaner and then drain it, you will NOT be at a 50-50 concentration if you add just 50-50 mixture. Don't forget that you will still have quite a bit of plain distilled water in the engine. You will need a stronger final concentration of antifreeze to GET to a final 50-50 mixture. Be sure to verify with a hydrometer (available at any parts store) Use conventional (green) antifreeze.

Dollar for dollar, no better money spent than that spent on your cooling system.
X2 on all this, just a tip to save some $$, instead of the radiator cleaner use a 50/50 solution of water/vinegar. X100 on not using the petcock on the radiator, plastic and years of heat do not mix well.
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Old Jan 3, 2012 | 08:46 AM
  #5  
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From: New England
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Won't all of the distilled water drain out when I am flushing it? Where will it remain?
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Old Jan 3, 2012 | 09:09 AM
  #6  
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From: The Republic of TEXAS
Year: 1998
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Engine: 4.0L HO
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The cooling system, mainly the block, will retain +/-1 gal of water unless the block is drained. The block plug(s) can be very difficult to remove and it's not really necessary to drain the block. The 1st gal of coolant added should be 100% straight coolant, then finish off with 50/50.

The best way to flush the block is with the t-stat cover and water pump removed.......stick a garden hose in the t-stat hole (head) and flush the head/block until clear water runs out the water pump hole (block). Use the garden hose to flush the heater core and as tj suggested, install a new rad. Using this method to flush, u won't be pushing chemicals/crud from/thru one component to another.

Last edited by djb383; Jan 3, 2012 at 09:20 AM.
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