Rebuilt Jag XK engine - coolant advice
Discussion
We are in the process of building an SS100 replica, the 4.2 engine for which came from a deceased family member's 1970 series 1 XJ6. This engine was completely rebuilt in around 2014 by an old gentleman who specialised in XK engines- who I believe is now sadly deceased. Regardless, as part of the rebuild process the engine was chemically cleaned- with the intention being to run the car with Evans waterless coolant.
In recent years there seems to be a lot of negative comments online around the Evans coolant - poorer heat dissipation, flammability, issues with water pumps not being up to the task etc. I broadly understand the science behind why it would have poorer cooling than a traditional water + coolant mix, but the trade-off being no internal corrosion, much lower pressure, and no boiling off under very high temps. It would be going into an effectively brand new system (rebuilt engine, brand new aluminium rad, pipes, thermostat etc), so we are not looking for it to be a band-aid for a tired cooling system- it's the long term preservation benefits and lower pressure that appeal.
We are rapidly approaching the point where we really need to make a decision soon on whether or not to go with it- so I just wondered if anyone on here had any experience with it specifically in relation to the XK engine, or could offer any thoughts that might better inform our decision?!
In recent years there seems to be a lot of negative comments online around the Evans coolant - poorer heat dissipation, flammability, issues with water pumps not being up to the task etc. I broadly understand the science behind why it would have poorer cooling than a traditional water + coolant mix, but the trade-off being no internal corrosion, much lower pressure, and no boiling off under very high temps. It would be going into an effectively brand new system (rebuilt engine, brand new aluminium rad, pipes, thermostat etc), so we are not looking for it to be a band-aid for a tired cooling system- it's the long term preservation benefits and lower pressure that appeal.
We are rapidly approaching the point where we really need to make a decision soon on whether or not to go with it- so I just wondered if anyone on here had any experience with it specifically in relation to the XK engine, or could offer any thoughts that might better inform our decision?!
Personally I wouldn't bother with waterless - the fundamental purpose of a coolant is to draw heat out of the engine and exhaust it into the atmosphere and nothing does that better than plain old water.... The problem with water is it's propensity to freeze and corrode metals, hence the antifreeze and corrosion inhibitors in coolants.
Back when your Jag engine was made an Ethyl Glycol antifreeze would have been standard - it's good at preventing water freezing and protecting all the sorts of metals found in old cooling systems, but degrades over time, becoming more acidic, hence the corrosion inhibiters and the necessity to change it regularly.
Then came the more modern technologies of IATs and OATs, OATs being by far the most prevalent nowadays. They're better than Ethyl Glycol type antifreezes as they still prevent the water from freezing, have better heat transfer than Ethyl Glycol type antifreezes and are much much longer lasting. The point to note about OATs is that they won't protect certain metals like copper and brass, though they are very good at protecting aluminium and iron.
So, as with everything it comes down to picking the right product for your application. Given that your engine is effectively 'new' so you are starting with a clean, new system, what is the right antifreeze to use? The answer will start with what metals you have in your cooling system - if it's all just aluminium and iron, an OAT antifreeze will be an excellent choice. If you've got a brass heater matrix or copper pipes or there are soldered joints in the system you will want to use a traditional Ethyl Glycol antifeeze, avoid OAT and change it regularly. I suspect this is the point at which you've considered going Evans waterless as you never have to change it. There are several points to bear in mind with waterless - it isn't as good at heat transfer, though it can deal with that by having a far higher boiling point. Its more viscous so doesn't flow around a cooling system in the same way water based does and it may require a different type of water pump. It's expensive and it will find every opportunity to leak! It will creep through microscopic gaps water based coolants won't. Importantly, it won't indicate a problem like a traditional water-based system will. A traditional system will boil off if it gets too hot giving a good visual indicator you have an issue, with waterless coolant it will just get hotter and hotter and potentially risk warping and damage to major components unless you happen to spot on your instruments that you have a problem. Further, if you do have a problem when you are out and about and lose a load of coolant, a traditional system can just be topped off with whatever you can find that has water in it... you can't do that with waterless.
Overall I don't opt for waterless coolant in any of my classics and choose whatever is appropriate for the cooling system, changing it regularly. For me, it's the best compromise between technology, sympathy for old cars and comfort, knowing I can get myself home if I have a problem and the fix afterwards isn't going to be expensive and time consuming. You may have different priorities but hopefully the above might help clarify your options.
I do use Dot5 silicone brake fluid in some brake and clutch applications though, so I'm not a total luddite!
Back when your Jag engine was made an Ethyl Glycol antifreeze would have been standard - it's good at preventing water freezing and protecting all the sorts of metals found in old cooling systems, but degrades over time, becoming more acidic, hence the corrosion inhibiters and the necessity to change it regularly.
Then came the more modern technologies of IATs and OATs, OATs being by far the most prevalent nowadays. They're better than Ethyl Glycol type antifreezes as they still prevent the water from freezing, have better heat transfer than Ethyl Glycol type antifreezes and are much much longer lasting. The point to note about OATs is that they won't protect certain metals like copper and brass, though they are very good at protecting aluminium and iron.
So, as with everything it comes down to picking the right product for your application. Given that your engine is effectively 'new' so you are starting with a clean, new system, what is the right antifreeze to use? The answer will start with what metals you have in your cooling system - if it's all just aluminium and iron, an OAT antifreeze will be an excellent choice. If you've got a brass heater matrix or copper pipes or there are soldered joints in the system you will want to use a traditional Ethyl Glycol antifeeze, avoid OAT and change it regularly. I suspect this is the point at which you've considered going Evans waterless as you never have to change it. There are several points to bear in mind with waterless - it isn't as good at heat transfer, though it can deal with that by having a far higher boiling point. Its more viscous so doesn't flow around a cooling system in the same way water based does and it may require a different type of water pump. It's expensive and it will find every opportunity to leak! It will creep through microscopic gaps water based coolants won't. Importantly, it won't indicate a problem like a traditional water-based system will. A traditional system will boil off if it gets too hot giving a good visual indicator you have an issue, with waterless coolant it will just get hotter and hotter and potentially risk warping and damage to major components unless you happen to spot on your instruments that you have a problem. Further, if you do have a problem when you are out and about and lose a load of coolant, a traditional system can just be topped off with whatever you can find that has water in it... you can't do that with waterless.
Overall I don't opt for waterless coolant in any of my classics and choose whatever is appropriate for the cooling system, changing it regularly. For me, it's the best compromise between technology, sympathy for old cars and comfort, knowing I can get myself home if I have a problem and the fix afterwards isn't going to be expensive and time consuming. You may have different priorities but hopefully the above might help clarify your options.
I do use Dot5 silicone brake fluid in some brake and clutch applications though, so I'm not a total luddite!
100% as per larrylamb11.
I have rebuilt a good number of XK engines and would not consider a waterless coolant. XK engines are very simple, do run 'hot...' and need no added complexity, just good quality traditional coolant that's changed every few years. The added advantage of being able to detect any potential cooling system issues can not be underestimated and makes for simple fault diagnosis.
I remember Roger Williams of Suffolk Jaguar having a thing for the much maligned 2.8ltr engine despite the much free'er rev'ing engine. There used to be a YouTube video of Roger hustling along one of his tremendous Suffolk Jaguar SS100's with the 2.8 engine. Alas, Suffolk Jaguar are no more.
SS100's are great looking cars and owning one is on my bucket list. Good luck with the build / post pics when completed.
I have rebuilt a good number of XK engines and would not consider a waterless coolant. XK engines are very simple, do run 'hot...' and need no added complexity, just good quality traditional coolant that's changed every few years. The added advantage of being able to detect any potential cooling system issues can not be underestimated and makes for simple fault diagnosis.
I remember Roger Williams of Suffolk Jaguar having a thing for the much maligned 2.8ltr engine despite the much free'er rev'ing engine. There used to be a YouTube video of Roger hustling along one of his tremendous Suffolk Jaguar SS100's with the 2.8 engine. Alas, Suffolk Jaguar are no more.
SS100's are great looking cars and owning one is on my bucket list. Good luck with the build / post pics when completed.
larrylamb11 said:
Personally I wouldn't bother with waterless - the fundamental purpose of a coolant is to draw heat out of the engine and exhaust it into the atmosphere and nothing does that better than plain old water.... The problem with water is it's propensity to freeze and corrode metals, hence the antifreeze and corrosion inhibitors in coolants.
Back when your Jag engine was made an Ethyl Glycol antifreeze would have been standard - it's good at preventing water freezing and protecting all the sorts of metals found in old cooling systems, but degrades over time, becoming more acidic, hence the corrosion inhibiters and the necessity to change it regularly.
Then came the more modern technologies of IATs and OATs, OATs being by far the most prevalent nowadays. They're better than Ethyl Glycol type antifreezes as they still prevent the water from freezing, have better heat transfer than Ethyl Glycol type antifreezes and are much much longer lasting. The point to note about OATs is that they won't protect certain metals like copper and brass, though they are very good at protecting aluminium and iron.
So, as with everything it comes down to picking the right product for your application. Given that your engine is effectively 'new' so you are starting with a clean, new system, what is the right antifreeze to use? The answer will start with what metals you have in your cooling system - if it's all just aluminium and iron, an OAT antifreeze will be an excellent choice. If you've got a brass heater matrix or copper pipes or there are soldered joints in the system you will want to use a traditional Ethyl Glycol antifeeze, avoid OAT and change it regularly. I suspect this is the point at which you've considered going Evans waterless as you never have to change it. There are several points to bear in mind with waterless - it isn't as good at heat transfer, though it can deal with that by having a far higher boiling point. Its more viscous so doesn't flow around a cooling system in the same way water based does and it may require a different type of water pump. It's expensive and it will find every opportunity to leak! It will creep through microscopic gaps water based coolants won't. Importantly, it won't indicate a problem like a traditional water-based system will. A traditional system will boil off if it gets too hot giving a good visual indicator you have an issue, with waterless coolant it will just get hotter and hotter and potentially risk warping and damage to major components unless you happen to spot on your instruments that you have a problem. Further, if you do have a problem when you are out and about and lose a load of coolant, a traditional system can just be topped off with whatever you can find that has water in it... you can't do that with waterless.
Overall I don't opt for waterless coolant in any of my classics and choose whatever is appropriate for the cooling system, changing it regularly. For me, it's the best compromise between technology, sympathy for old cars and comfort, knowing I can get myself home if I have a problem and the fix afterwards isn't going to be expensive and time consuming. You may have different priorities but hopefully the above might help clarify your options.
I do use Dot5 silicone brake fluid in some brake and clutch applications though, so I'm not a total luddite!
Thanks for the extremely detailed, informative post- exactly what I was after!Back when your Jag engine was made an Ethyl Glycol antifreeze would have been standard - it's good at preventing water freezing and protecting all the sorts of metals found in old cooling systems, but degrades over time, becoming more acidic, hence the corrosion inhibiters and the necessity to change it regularly.
Then came the more modern technologies of IATs and OATs, OATs being by far the most prevalent nowadays. They're better than Ethyl Glycol type antifreezes as they still prevent the water from freezing, have better heat transfer than Ethyl Glycol type antifreezes and are much much longer lasting. The point to note about OATs is that they won't protect certain metals like copper and brass, though they are very good at protecting aluminium and iron.
So, as with everything it comes down to picking the right product for your application. Given that your engine is effectively 'new' so you are starting with a clean, new system, what is the right antifreeze to use? The answer will start with what metals you have in your cooling system - if it's all just aluminium and iron, an OAT antifreeze will be an excellent choice. If you've got a brass heater matrix or copper pipes or there are soldered joints in the system you will want to use a traditional Ethyl Glycol antifeeze, avoid OAT and change it regularly. I suspect this is the point at which you've considered going Evans waterless as you never have to change it. There are several points to bear in mind with waterless - it isn't as good at heat transfer, though it can deal with that by having a far higher boiling point. Its more viscous so doesn't flow around a cooling system in the same way water based does and it may require a different type of water pump. It's expensive and it will find every opportunity to leak! It will creep through microscopic gaps water based coolants won't. Importantly, it won't indicate a problem like a traditional water-based system will. A traditional system will boil off if it gets too hot giving a good visual indicator you have an issue, with waterless coolant it will just get hotter and hotter and potentially risk warping and damage to major components unless you happen to spot on your instruments that you have a problem. Further, if you do have a problem when you are out and about and lose a load of coolant, a traditional system can just be topped off with whatever you can find that has water in it... you can't do that with waterless.
Overall I don't opt for waterless coolant in any of my classics and choose whatever is appropriate for the cooling system, changing it regularly. For me, it's the best compromise between technology, sympathy for old cars and comfort, knowing I can get myself home if I have a problem and the fix afterwards isn't going to be expensive and time consuming. You may have different priorities but hopefully the above might help clarify your options.
I do use Dot5 silicone brake fluid in some brake and clutch applications though, so I'm not a total luddite!
v8250 said:
100% as per larrylamb11.
I have rebuilt a good number of XK engines and would not consider a waterless coolant. XK engines are very simple, do run 'hot...' and need no added complexity, just good quality traditional coolant that's changed every few years. The added advantage of being able to detect any potential cooling system issues can not be underestimated and makes for simple fault diagnosis.
Thank you - I think this is looking like the route we will go down.I have rebuilt a good number of XK engines and would not consider a waterless coolant. XK engines are very simple, do run 'hot...' and need no added complexity, just good quality traditional coolant that's changed every few years. The added advantage of being able to detect any potential cooling system issues can not be underestimated and makes for simple fault diagnosis.
v8250 said:
I remember Roger Williams of Suffolk Jaguar having a thing for the much maligned 2.8ltr engine despite the much free'er rev'ing engine. There used to be a YouTube video of Roger hustling along one of his tremendous Suffolk Jaguar SS100's with the 2.8 engine. Alas, Suffolk Jaguar are no more.
SS100's are great looking cars and owning one is on my bucket list. Good luck with the build / post pics when completed.
I will certainly post some pictures up at some point!SS100's are great looking cars and owning one is on my bucket list. Good luck with the build / post pics when completed.
That iteration of Suffolk is indeed no longer, but the new Suffolk Classic Services (nothing to do with Roger) are still heavily involved with the SS100 replicas- we speak with them on an almost weekly basis concerning our build and they have been incredibly helpful, both from a technical resource and supplying parts / fittings that were either missed previously or that have since been superseded by superior items. If you do look to get involved with an SS100 they are well worth giving a call.
For several decades I have thought that it is illogical to 'change coolant every few years' as suggested above. Corrosion is caused not by water but by the dissolved oxygen in the water. Once that is used up, no further corrosion can occur. Our rusty old Mk1 Focus went to the scrapyard at 21yrs old and >160,000 miles with its original pink coolant. The last time the coolant was added in my TR7 was in 2002 when I had to replace the water pump, and even then I did not completely drain it. It is now 44yrs old with admittedly only 73k miles but there is no coolant loss and no sign of CHG failure. The corrosion genie is delighted when coolant is changed because with fresh oxygen it can resume its erosive destruction!
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