Flushing cooling system for C4
Safety Car
Joined: Jul 2008
Posts: 3,966
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From: Made In America
St. Jude Donor '10-'11
Thanks for the compliment -- I wrote-up those instructions for a different post based on our 1994 LT1.
The one improvement I've discussed with other members since, was to also use the shop-vac in blower-mode to push additional coolant/debris out of the engine, after each draining -- blow air into the black pressure tank where the radiator cap goes, it will help remove additional debris that might remain in the engine near the 'knock-sensors', eliminating the need to remove them to completely drain the block.
Regarding the cost/quantity of distilled water, I also have well water so can't use, but considering the 12-16 gallons of distilled-water only cost $12-$16, it's well worth it to assure nice clean water in the block.
The one improvement I've discussed with other members since, was to also use the shop-vac in blower-mode to push additional coolant/debris out of the engine, after each draining -- blow air into the black pressure tank where the radiator cap goes, it will help remove additional debris that might remain in the engine near the 'knock-sensors', eliminating the need to remove them to completely drain the block.
Regarding the cost/quantity of distilled water, I also have well water so can't use, but considering the 12-16 gallons of distilled-water only cost $12-$16, it's well worth it to assure nice clean water in the block.
Race Director
Joined: Mar 2006
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From: Sherwood, Arkansas
Race Director
Joined: Apr 2003
Posts: 17,699
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From: moraga ca
Where are the drain plugs on an L98? And can those be removed without having to lift the car or use ramps?
And when flushing, instead of running it till it gets to operating temp, could you just remove the thermostat and run it? Or is there another purpose of letting it get to operating temp with regards to a flush?
And when flushing, instead of running it till it gets to operating temp, could you just remove the thermostat and run it? Or is there another purpose of letting it get to operating temp with regards to a flush?
The drain plugs are above the oil pan on each side of the block. On the earlier c4s the passanger side has a knock sensor, the drivers side has either a plug or a fitting for the oil cooler/heat exchanger. The car does need to be in the air to access these. If the thermostat is out, the motor only has to run for a couple of minutes so the fresh water can mix with any undrained fluid or gunk and then drained out after shutdown.
Safety Car
Joined: Jan 2004
Posts: 3,759
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The drain plugs are above the oil pan on each side of the block. On the earlier c4s the passanger side has a knock sensor, the drivers side has either a plug or a fitting for the oil cooler/heat exchanger. The car does need to be in the air to access these. If the thermostat is out, the motor only has to run for a couple of minutes so the fresh water can mix with any undrained fluid or gunk and then drained out after shutdown.
Then I'd drain it and fill it with distilled and flush with that a couple times to get all the water from the hose out. Then do 50/50.
Does the throttle body coolant hoses drain through the block. I'll be pulling the throttle body, and figured I could spray some water down the hoses to clear that all out. I've got some sludge in the radiator which is while I'm wanted to flush everything out and make sure there is no gunk build up anywhere.
Safety Car
Joined: Jan 2004
Posts: 3,759
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After you drain the block via removing the knock sensors. When you bolt everything back up to refill it the last time, do you just put coolant in the radiator? I figured that would leave the block empty. I'm guessing you also put coolant in the thermostat opening?
And instead of draining/refilling with water, what about just removing all the hoses and drain plugs, and running water through the thermostat opening, and through the heater hoses going into the block? I figured that would flush everything better.
And instead of draining/refilling with water, what about just removing all the hoses and drain plugs, and running water through the thermostat opening, and through the heater hoses going into the block? I figured that would flush everything better.
