Coolant drain question

I am attempting to replace the green stuff in my LP400S with Evans NPG coolant. When I rebuilt the engine in my LP5000S I noticed how much metal had eroded from the steel liners in the block; I am going to try the Evans NPG as it does not run under pressure or cause corrosion. I also hate changing coolant every 2 years and like the idea of long life coolant.

 

To achieve the desired result, residual water should be less than 3% of the total volume when the NPG is added.

 

The stock coolant capacity of a LP400S is 17 liters. To get it out I pulled the hoses off the water pump, removed the plugs on eitther side of the block and pushed a lot of compressed air through the system from the coolant tank cap.

 

I drained 15 from it this way and added 12 liters of "prep fluid", something which is supposed to absorb the remaining water and remove residue.

 

After running the engine up to temperature with the heater valve open (the thermostat opened up) I drained the prep fluid and retrieved about 9 liters of the stuff using both the water pump hoses and by removing the plugs on the sides of the block. The prep fluid turned green so there must have been some leftover coolant somewhere in the system.

 

I then blew compressed air through the heater core and got about another 500cc out it.

 

What makes me curious is where the remaining water might be hiding. The spigot at the bottom of the water pump housing should be the low point of the system, but I realize that the hoses which run from the engine to the heater core go under the door sill on the right side. One thought is to undo the hoses where they connect to the heater core in the front of the car and blow compressed air through it.

 

Anything I am missing? Having completely disassembled a LP5000S to the last nut (and reassembled about 60% of it) I thought I knew the Countach anatomy pretty well. Perhaps not.

 

 

I can not say for sure. I do know there are areas of nook and crannies that you won't get out. I do not know if this is the amount missing. As you can imagine, if you had the motor on a stand and spun it, that fluid will all come out. It's in there. Hopefully NOT in the oil via head gaskets (which I doubt on your motor).

I've always learned to keep flushing.

 

I am always nervous when blowing compressed air in a cooling system. I seen many times heater cores and maybe some other thing go. Especially in old cars.

 

Sorry, I could not be more help. Maybe Vic or someone has more insight.

I am attempting to replace the green stuff in my LP400S with Evans NPG coolant. When I rebuilt the engine in my LP5000S I noticed how much metal had eroded from the steel liners in the block; I am going to try the Evans NPG as it does not run under pressure or cause corrosion. I also hate changing coolant every 2 years and like the idea of long life coolant.

 

To achieve the desired result, residual water should be less than 3% of the total volume when the NPG is added.

 

The stock coolant capacity of a LP400S is 17 liters. To get it out I pulled the hoses off the water pump, removed the plugs on eitther side of the block and pushed a lot of compressed air through the system from the coolant tank cap.

 

I drained 15 from it this way and added 12 liters of "prep fluid", something which is supposed to absorb the remaining water and remove residue.

 

After running the engine up to temperature with the heater valve open (the thermostat opened up) I drained the prep fluid and retrieved about 9 liters of the stuff using both the water pump hoses and by removing the plugs on the sides of the block. The prep fluid turned green so there must have been some leftover coolant somewhere in the system.

 

I then blew compressed air through the heater core and got about another 500cc out it.

 

What makes me curious is where the remaining water might be hiding. The spigot at the bottom of the water pump housing should be the low point of the system, but I realize that the hoses which run from the engine to the heater core go under the door sill on the right side. One thought is to undo the hoses where they connect to the heater core in the front of the car and blow compressed air through it.

 

Anything I am missing? Having completely disassembled a LP5000S to the last nut (and reassembled about 60% of it) I thought I knew the Countach anatomy pretty well. Perhaps not.

 

 

 

 

You can disconnect the heater hoses at the engine and lightly blow air into one of the hoses and it will exit the other

I thought about that, to reach the end of the hose near the firewall would be a tough job, especially with the engine lid in place.

 

I will continue to experiment - fwiw I do not use a powerful compressor to push out the water, rather a Bosch shop air blower thing.

 

Maybe I need some more prep fluid and must do the whole rinse once more. A real pain, to run it the exhaust must be on. To remove the block plugs the rear half of the manifolds come off. Do that a couple of times. Not to mention that prep stuff is kinda pricey here.

Very interesting, thanks for sharing. Standard antifreeze coolant fluid durability without wearing aluminium is four years, so if you drain the cooling system every three years (or even four) you may not care about 500 cc of old coolant hided somewhere. Just wash the cooling system with demineralized water before adding the new coolant mixture. Those erosion you saw is probably due to 10+ years old coolant.

I cannot help you about this issue, i never did nor saw this operation done.

 

ciao

My guess is the heater core still has some coolant in it. I am trying to undo the hose which connects to the header core at the firewall but it is very hard to reach it with the engine in place.

 

I always replace the coolant every 2 years (brake fluid too) but removing all of the coolant is much harder. I have been testing the NPG on my R1 and my MX bike and it seems to work well. No overheating, no pressure in the system.

My guess is the heater core still has some coolant in it. I am trying to undo the hose which connects to the header core at the firewall but it is very hard to reach it with the engine in place.

 

I always replace the coolant every 2 years (brake fluid too) but removing all of the coolant is much harder. I have been testing the NPG on my R1 and my MX bike and it seems to work well. No overheating, no pressure in the system.

 

This time i learned something: thank you very much.

 

Will do it next time.

 

 

ciao