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Feb 20, 2015 11:53 pm
Feb 20, 2015 11:53 pm
Subject: Re: 4.5 litre engine problems and upgrades
Ethylene Glycol plus inhibitors is the commonly used car antifreeze in older vehicles (usually blue or green) and the thermal conductivity is approx half or less than that of water.
In high concentration levels, as needed for winter protection, it will mean that the engine is more likely to boil as is not able to carry the heat away as well as fresh water.
Personally I run my old cars on a relatively high ethylene glycol concentration (30 to 50% in winter and dump the antifreeze in the Spring, retaining only about 5% to keep some corrosion protection. Dumping this ethylene glycol antifreeze annually also makes sense because it only has approx. 2 year life before the inhibitors are "used up".
When they are "used up" these silicate inhibitors tend to come out of solution and cause wear to water pump seals / bearings.
Nasty gels also form which bung up the system aside from the corrosive nature of gylcol when the corrosion inhibitor is used up.
From Google:
Fluid Thermal Conductivity at 300 K ( + 27 degrees C)
(W/m K)
Ethylene Glycol = 0.258 versus Water, Fresh = 0.609
I am not sure what chemical is actually in the "waterless" antifreeze either.
I tried a particular waterless type in a Mk VI Bentley we had which had been prone to overheating as they claimed that the thermal capacity was better than water but I found that it did two things:
1. It acted as a very good flushing agent and cleaned all the dirt out of the engine, depositing it in the radiator so it was just as well we needed to re-core the radiator anyway!
2. It was far more "searching" than ethylene glycol and found every possible place to leak out of!
so it might work well with systems that are totally clean and leak free but I would not introduce it to an older engine that had previously been used on water unless it had been meticulously cleaned inside ...
So, having cleaned the engine out I re-cored the rad, reverted to ethylene glycol and fitted a new water pump which solved the problem and was what we should have done in the first place!
Hope this helps
Bill
Ethylene Glycol plus inhibitors is the commonly used car antifreeze in older vehicles (usually blue or green) and the thermal conductivity is approx half or less than that of water.
In high concentration levels, as needed for winter protection, it will mean that the engine is more likely to boil as is not able to carry the heat away as well as fresh water.
Personally I run my old cars on a relatively high ethylene glycol concentration (30 to 50% in winter and dump the antifreeze in the Spring, retaining only about 5% to keep some corrosion protection. Dumping this ethylene glycol antifreeze annually also makes sense because it only has approx. 2 year life before the inhibitors are "used up".
When they are "used up" these silicate inhibitors tend to come out of solution and cause wear to water pump seals / bearings.
Nasty gels also form which bung up the system aside from the corrosive nature of gylcol when the corrosion inhibitor is used up.
From Google:
Fluid Thermal Conductivity at 300 K ( + 27 degrees C)
(W/m K)
Ethylene Glycol = 0.258 versus Water, Fresh = 0.609
I am not sure what chemical is actually in the "waterless" antifreeze either.
I tried a particular waterless type in a Mk VI Bentley we had which had been prone to overheating as they claimed that the thermal capacity was better than water but I found that it did two things:
1. It acted as a very good flushing agent and cleaned all the dirt out of the engine, depositing it in the radiator so it was just as well we needed to re-core the radiator anyway!
2. It was far more "searching" than ethylene glycol and found every possible place to leak out of!
so it might work well with systems that are totally clean and leak free but I would not introduce it to an older engine that had previously been used on water unless it had been meticulously cleaned inside ...
So, having cleaned the engine out I re-cored the rad, reverted to ethylene glycol and fitted a new water pump which solved the problem and was what we should have done in the first place!
Hope this helps
Bill