Changing coolant V12

Talk about the E-Type Series 3
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Mephistopheles
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Joined: Sat Jan 06, 2018 10:00 am
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#1 Changing coolant V12

Post by Mephistopheles » Tue May 03, 2022 3:05 pm

I have found many posts about replacing the coolant, however, I still have the following questions before I want to replace the coolant in my E Type V12 myself:

0. Is there a simple way to analyse whether the anti-corrosion additives in silicate cooling water (that is still clear and of blue-green color) are still effective?

The total amount of cooling water in the V12 engine is approximately 20 litres.
1. How many litres does the "small" cooling water circuit have, i.e. the amount of cooling water in the engine?

There is a tap in the lower part of the radiator as the only intended cooling water drainage option:
2. is it advisable to drain the cooling water by loosening the lowest water hose instead of opening the tap (is there a risk that the tap will no longer close tightly)?
3. Does this drain the entire coolant volume (approx. 20 l), i.e. including the volume from the engine ("small coolant circuit"), or only the coolant volume from the radiator, or do the thermostats have to be open to drain the entire coolant (i.e. warm engine with coolant warmer than 82°C) or do the thermostats have to be removed when the engine is cold?

I interpret from several posts that the ability of the coolant system to self-vent is limited, so when topping up with coolant, park uphill so that the header tank is higher than the heater or bleed manually by disconnecting the heater water hose.
4. are there any bleed valves that can be retrofitted and is this advisable?

5. what else do I have to consider when filling up with cooling water; does a cold engine (cooling water colder than 82°C) with "closed" thermostats prevent complete filling with cooling water?

Thank you very much for the answers!

Regards

Holger
1973 manual LHD OTS E Type
Holger

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Redman
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#2 Re: Changing coolant V12

Post by Redman » Fri Jul 21, 2023 7:51 am

I wouldn't mind having this information too. Anyone?
Gordon James
S3 1971 - Original (JHT) LHD/Auto/Air Con. Re-imported from US via UK in 1994, rebuilt Antwerp. Dk Blue (orig Sable)/Biscuit (orig Beige)
Porsche 911SC 1983
VW T2A Bus 1971
VW Beetle Cabrio 1967 (but bit of a mixture!)

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jagwit
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#3 Re: Changing coolant V12

Post by jagwit » Wed Jul 26, 2023 12:26 pm

Mephistopheles wrote:
Tue May 03, 2022 3:05 pm
0. Is there a simple way to analyse whether the anti-corrosion additives in silicate cooling water (that is still clear and of blue-green color) are still effective?

The total amount of cooling water in the V12 engine is approximately 20 litres.
1. How many litres does the "small" cooling water circuit have, i.e. the amount of cooling water in the engine?
0. No idea
1. No idea
Mephistopheles wrote:
Tue May 03, 2022 3:05 pm
There is a tap in the lower part of the radiator as the only intended cooling water drainage option:
2. is it advisable to drain the cooling water by loosening the lowest water hose instead of opening the tap (is there a risk that the tap will no longer close tightly)?
2. Lowest hose yes. It should be possible to remove the tap and clean/polish it for a good seal. My car has a drain plug in one of the hose mounts that routes coolant through the sump.
Mephistopheles wrote:
Tue May 03, 2022 3:05 pm
3. Does this drain the entire coolant volume (approx. 20 l), i.e. including the volume from the engine ("small coolant circuit"), or only the coolant volume from the radiator, or do the thermostats have to be open to drain the entire coolant (i.e. warm engine with coolant warmer than 82°C) or do the thermostats have to be removed when the engine is cold?
3. It should drain MOST of the coolant but I estimate that 3-4 Liters should remain in the lower hoses and coolant circuit. Thermostats do not have to be open and no need to remove them either. IF they are the correct thermostats, they should have a jiggle pin that would help with drainage although that is not the main reason for the jiggle pin. I would open the filler cap to allow fastest draining.
Mephistopheles wrote:
Tue May 03, 2022 3:05 pm

4. are there any bleed valves that can be retrofitted and is this advisable?

5. what else do I have to consider when filling up with cooling water; does a cold engine (cooling water colder than 82°C) with "closed" thermostats prevent complete filling with cooling water?
4. No bleed valves necessary.
5. No special method of filling cooling system. The jiggle pins in the thermostats would help filling by allowing air trapped under the stats to be purged quickly.

MY METHOD of coolant removal:
1. Run a 3/8" (10mm ID) pipe down the pipe that runs vertically from the expansion tank all the way down to the bottom hose between engine and radiator.
2. Siphon the coolant out. (I have a pipe with marble valve at the one end. Jiggling the pipe rapidly up and down starts the siphoning process. )
3. I recon this method gets at least 18L out of the engine.
4. No need to disconnect any pipes.
5. Very quick to drain the system.
Best Regards
Philip
Jag: 72 S3 XKE, 74 S3 XKE OTS, 80 XJS (Megasquirt + 5sp manual O/D)
Jensen: 74 Interceptor (EFI by Megasquirt + O/D 4sp auto)
Chev: 59 Apache std, 70 C10 (350V8, 700R4)

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Redman
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#4 Re: Changing coolant V12

Post by Redman » Thu Jul 27, 2023 9:06 pm

Many thanks, Phillip. Appreciated.
Gordon James
S3 1971 - Original (JHT) LHD/Auto/Air Con. Re-imported from US via UK in 1994, rebuilt Antwerp. Dk Blue (orig Sable)/Biscuit (orig Beige)
Porsche 911SC 1983
VW T2A Bus 1971
VW Beetle Cabrio 1967 (but bit of a mixture!)

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