rj Posted May 14, 2019 Share Posted May 14, 2019 But I thought that you were looking at alternative specs because of problems with availability rather than any advantage.+1 Link to comment Share on other sites More sharing options...
CageyH Posted May 14, 2019 Author Share Posted May 14, 2019 I was. It just so happens that the G13 is the updated version of what the Comma G30 is, and the G13 is readily available, being used by the VAG group. Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted May 14, 2019 Member Share Posted May 14, 2019 Thanks.From the limited amount of information I've been able to find on the composition of G13 I'd want to know about the following before putting it in my Seven:The change in heat transfer capacity and viscosity following the replacement of some ethylene glycol with glycerine. But I haven't seen any adverse comments about this and I don't know that Sevens are different from anything else.The corrosion protection for the block, head etc. Ditto.The risk of corrosion to copper and brass components, lead solder etc. Possibly highest in the radiator, heater, heater valve, brass T pieces etc. VAG would have total control over avoiding those in their new models whereas our Sevens have all sorts of bits and pieces.Jonathan Link to comment Share on other sites More sharing options...
rj Posted May 14, 2019 Share Posted May 14, 2019 I'd be very surprised if there was any lead even in my 1995 car except from in the electronics. Link to comment Share on other sites More sharing options...
CageyH Posted May 14, 2019 Author Share Posted May 14, 2019 The corrosion protection for aluminium is good. It is what it is designed for. Link to comment Share on other sites More sharing options...
Wrightpayne Posted May 14, 2019 Share Posted May 14, 2019 I think Jonathan was referring to other types of metals in a typical seven cooling system - copper soldered rad and heater rad, steel submarine pipe etc Link to comment Share on other sites More sharing options...
rj Posted May 14, 2019 Share Posted May 14, 2019 My radiator is plastic and aluminium. The submarine is steel, but would it have been soldered with lead? (And of course the same question for the water rail).Next generation Silllylight will have alloy tubes as well. Link to comment Share on other sites More sharing options...
CageyH Posted May 14, 2019 Author Share Posted May 14, 2019 G13 is also good for cast iron and ferrous aluminium.Not sure about copper. Link to comment Share on other sites More sharing options...
CageyH Posted May 14, 2019 Author Share Posted May 14, 2019 However, G13 is not ideal for older cooling systems with copper/brass radiators and heater cores (it doesn’t integrate well with the lead solder). Antifreeze with G11 or G12 specification should be used instead.I guess it’s not a good idea then if you copper or brass in the system. Link to comment Share on other sites More sharing options...
CageyH Posted May 14, 2019 Author Share Posted May 14, 2019 My car has a Clayton heater fitted which dates from 1997. Is this likely to be brass and copper or aluminium and plastic? Link to comment Share on other sites More sharing options...
Wrightpayne Posted May 14, 2019 Share Posted May 14, 2019 Brass - they use a ‘proper’ mini heater matrix IIRC Link to comment Share on other sites More sharing options...
CageyH Posted May 14, 2019 Author Share Posted May 14, 2019 I guess I will be changing the coolant out sooner rather than later then. What is the Prestone stuff based on? Link to comment Share on other sites More sharing options...
Wrightpayne Posted May 14, 2019 Share Posted May 14, 2019 Just had a look on ebay and lots of ally / plastic heater cores available for the classic mini (if it is in fact from a mini - not 100% sure) Link to comment Share on other sites More sharing options...
CageyH Posted May 14, 2019 Author Share Posted May 14, 2019 If you google Motor rads they offer a high quality matrix, which is brass and copper as a replacement for the Caterham, and they state it is based on a mini. Link to comment Share on other sites More sharing options...
CageyH Posted May 15, 2019 Author Share Posted May 15, 2019 A little further reading also reveals that OAT coolant is not good for copper or brass either. So I don’t see G13 coolant being any worse than Comma G30. However, if you have a heater, I would try and avoid both. A traditional coolant (the old Comma blue or green) or maybe the Prestone is looking like the best choice. Link to comment Share on other sites More sharing options...
CageyH Posted May 15, 2019 Author Share Posted May 15, 2019 I have dropped Holts an email to see if Prestone is compatible with brass and copper radiators. If it is, then I would suggest that this is the best coolant for cars with heaters fitted. Link to comment Share on other sites More sharing options...
CageyH Posted May 15, 2019 Author Share Posted May 15, 2019 Holts have replied. It is compatible with brass and copper, so it will be goodbye OAT, hello Prestone.Thanks DaveJ for bringing the Prestone to my attention. Link to comment Share on other sites More sharing options...
Wrightpayne Posted May 15, 2019 Share Posted May 15, 2019 Their screenwash is my current brand of choice - I try and stick to one make as I had an unfortunate slime blockage incident a few years ago needing the whole inner arch stripping out to get to the reservoir. Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted May 15, 2019 Member Share Posted May 15, 2019 Holts have replied. It is compatible with brass and copper, so it will be goodbye OAT, hello Prestone.Which Prestone coolant was that for, please?ThanksJonathan Link to comment Share on other sites More sharing options...
revilla Posted May 15, 2019 Share Posted May 15, 2019 Just make sure that whatever you choose, it is not only compatible with all of the metals individually but will suppress the galvanic corrosion which would otherwise occur where for example the steel liners sit in contact with the aluminium head. Dissimilar metals in contact in an electrolyte are just looking for trouble.I recently had to put a lot of time into rebuilding somebody's engine after they used pure water for just a short time. The corrosion pitting of the head face and the block deck in close proximity to the liners was shocking. It had actually eaten quite deeply into the metal, leaving it spongy and porous and needed aggressive peening and skimming to recover it.It eventually ate the aluminium around the fire rings to the point where the head gasket failed. It left the head with what looked superficially like the normal indentation caused by annealing of the alloy, but on Dave Andrews' tester the metal was still as hard as the day it left Longbridge. It was just the galvanic action at the point of contact that did the damage in the absence of corrosion inhibitors. Link to comment Share on other sites More sharing options...
CageyH Posted May 15, 2019 Author Share Posted May 15, 2019 If JK, This is the one I asked about - https://www.holtsauto.com/prestone/products/coolant-antifreeze-ready-use/ but I ordered 4 litres of concentrate for €24. The electrolytic corrosion caused by copper and aluminium is something that is concerning, so I may look to see if I can find a high quality aluminium matrix when my current matrix fails. Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted May 15, 2019 Member Share Posted May 15, 2019 Thanks.Holts have replied. It is compatible with brass and copper, so it will be goodbye OAT, hello Prestone.According to Holts that Prestone coolant is an OAT.Jonathan Link to comment Share on other sites More sharing options...
CageyH Posted May 15, 2019 Author Share Posted May 15, 2019 Yes, I have just found that out. Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted May 15, 2019 Member Share Posted May 15, 2019 Just make sure that whatever you choose, it is not only compatible with all of the metals individually but will suppress the galvanic corrosion which would otherwise occur where for example the steel liners sit in contact with the aluminium head.Definitely. But how can an individual owner know?The suppliers don't disclose the formulation, except in general terms for safety compliance. And the chemistry of corrosion inhibition is very... complex. And they don't disclose the results of even medium-term tests. And probably don't do them, or anything beyond ASTM compliance or similar.That ignorance pushes me towards being very risk averse. Which is why I use what the engine manufacturer/ supplier recommends and a lot of other owners use.Jonathan Link to comment Share on other sites More sharing options...
CageyH Posted May 15, 2019 Author Share Posted May 15, 2019 In reality, it is probably only slightly different from the G13, so I am just going to use the G13. Link to comment Share on other sites More sharing options...
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