Dave Rothwell Posted February 12, 2003 Share Posted February 12, 2003 re my earlier posting today - I have been passed the outlet this afternoon and whatever the Comma Brand I saw last week was, it seems to have disappeared off the shelves. I'm sure I was'nt going dotty last week - I saw it, I did, mumble, mumble, hysterical laughter. However the good news is - if you live in the Lancs area, and even better somewhere near Rochdale - the town centre Carcraft superstore has litres and litres of Coldstream freshly stocked on the shelves at £9.99 for five litres. Hope this may at least help someone. Who needs a Helmet - Get an Affro ! Clickhere to see Car and AFFRO ! Member 6790 Superlight 0075 - K7 LYT Link to comment Share on other sites More sharing options...
Colin Grundy Posted February 13, 2003 Share Posted February 13, 2003 Thought you might be interested, but Ive just returned from Caterham parts, and while I was there I thought I might as well buy some Coldstream. Unfortunately, I was told, it is no longer manufactured and was also told that it has been superseded by Xtreme, which, as someone has already pointed out is now going in all of the new caterhams coming out of the factory, and presumably all of the customers cars being worked on. I left totally confused and still haven't any antifreeze. SO, what do I buy? Link to comment Share on other sites More sharing options...
Dave Rothwell Posted February 13, 2003 Share Posted February 13, 2003 Colin, As my post above - Carcraft had no Coldstream last week and now they have enough to take a bath in so I can't see that Comma are no longer producing it ( unless this was old stock - the bottles looked new ). Link to comment Share on other sites More sharing options...
V7 SLR Posted February 13, 2003 Share Posted February 13, 2003 Is it so important that you buy a Comma product? There's a Rover garage everywhere. Worcs L7 club joint AO.//Membership No. 4379//Azure Blue SLR No. 0077//Se7ens List Tours Link to comment Share on other sites More sharing options...
Bare Posted February 13, 2003 Share Posted February 13, 2003 This is Silly.. IF you must have the latest variation on Antifreeze. then Try Mercedes Benz (or it's cheaper cousin VW') coolant. Having said that I have heard my local Parts Distributors say that they prefer the "green" coloured stuff cuz they have seen too many perforated cylinder heads on the Merc/VW/Audi stuff... Don't even want to think about "rover" branded coolant .. not much of an enviable track record there :-) Methinks it's Purely a "grass is greener" situation.. changing the stuff is key.. not necessarily the brand name/type Link to comment Share on other sites More sharing options...
Peter Carmichael Posted February 13, 2003 Share Posted February 13, 2003 Well done Bare for intervening on a techtalk discussion that had got to the bottom of all the various types of coolant and reducing it to a brand values debate. Methinks you are missing the point. Link to comment Share on other sites More sharing options...
Chris W Posted February 13, 2003 Share Posted February 13, 2003 I think your condescension, in regard of Bare's remarks, is uncalled for Peter. As a newcomer to this forum, I have noticed it tends often to be your style. Surely everyone's contribution is welcome. Bare isn't missing the point, he's introducing a new one. It's from this pooling of ideas that we all learn. Who can tell what the "correct" answer will end up being on any particular issue. There are a range of right answers usually. 1.8K SV 140hp see it here Link to comment Share on other sites More sharing options...
Tony C Posted February 13, 2003 Share Posted February 13, 2003 Cough 😬 Still waiting for my BRG SV kit. 😬 Link to comment Share on other sites More sharing options...
puremalt Posted February 13, 2003 Share Posted February 13, 2003 Aluminium is amphoteric-ie it corrodes at low and high pH. The safe band that the coolant must work in will be 7.5 to 8.8; this is very tight. Not knowing enough about the antifreeze properties, but being involved in industrial water treatment for years, many metals have very specific galvanic properties. I would guess that the prescribed coolant (damn I've already forgotten the name!) will allow the cooling water to be at too high a pH hence causing corrosion and eating the ali away (I have seen an air conditioning plant in a bank collapse after less than 3 months due to this.) I would certainly not touch a coolant with silicates in it, this sounds like a recipe for precipitation of silicate scale- atremendous insulator. 1/8 " of scale is equal to 12" of metal as an insulator, this can knacker rads blocks etc when you start to hot sopt. Me, I put our own product containing nitrite, hydroxide and molybdate in my car, but then it is an old x flow. But then it is the best inhibitor money can buy, and I only use 10 ml to get a strong reserve. Beat that! Mine Farts and Belches Link to comment Share on other sites More sharing options...
Peter Carmichael Posted February 14, 2003 Share Posted February 14, 2003 My apologies. Sometimes the other pressures in my life mean I answer in haste. Perhaps it is worth summarising the mainstream coolant info that has been trawled up here: Traditional coolant: Ethylene glycol with an inhibitor package, mixed with water Varying level of silicates (and other additives) depending on formulation. Often green/blue. Silicates required to prevent damage to aluminium engines, but cause big problems if the package stability is compromised by overheating/contamination/you name it. Result is silicates dropping out as sludge which requires flushing radiator and block with a caustic flush. Silicates can also cause abrasion problems for the water pump. Sludging causes hotspots, reduced cooling efficiency of radiator. Loss of silicate package stability means it becomes heavily corrosive to any aluminium/soldered components. Toxic. Change frequently Dispose of carefully. Two teaspoons will kill a cat. Not much more to kill a child. OAT: Organic acid technology inhibitor package on top of an ethylene glycol base Typically orange Marketed as longer life, but been demonstrated to cause problems. Really bastard carcinogenic through skin absorption of small quantities. Nasty if you get near the fumes. Incompatible with copper/brass/soldered components (heaters/radiators) Q: Why does this stuff exist? A: Big business made it exist. GMC/Texaco etc. HOAT: Hybrid OAT. Not much better, but Ford avoiding GM patents. Propylene Glycol in 50:50 aqueous solution/Comma Coldstream/Rover 4 year coolant: Not so good at low temperatures (less than minus 10) because of viscosity problems. Typcially blue/green Essentially non-toxic, but keep it away from your liver and kidneys (skin absorption again). Specific properties that make it better for preventing aluminium heat rejecting surface corrosion, which is what kills K-series head gaskets. Inhibitor package doesn't require silicates, so no sludging. Evans NPG/Non-aqueous propylene glycol: An oddball option. All comes down to the inhibitor package. Can ditch your pressure cap, because it doesn't require a pressurised system Will not boil over. Has lower specific heat capacity, so temp gradient across the head will be higher and overall heat rejection of system will be lower at any given flow rate. Can require uprated water pumps/bigger radiators. Has propylene glycol problems of viscosity, so not suitable for ultra low temperatures. Very low vapour pressure, so apparently very good for cooling aluminium heads without hotspotting. Link to comment Share on other sites More sharing options...
Pierre Gillet Posted February 14, 2003 Share Posted February 14, 2003 Incompatible with copper/brass/soldered components (heaters/radiators) I hope you have been a little bit pessimistic there Peter, since I move recently to OAT and I have non ali radiator and heater! The issue I suppose is the rate of corrosion of the lead contained in welds. I figure that all coolants do corrode such welds at some point and that propylene- based coolants are no exception. Now at what rates? Pierre Link to comment Share on other sites More sharing options...
Bill Shurvinton Posted February 14, 2003 Share Posted February 14, 2003 I was thinking of scoring a couple of gallons of the evans NPG+ on my next trip to the US, as they don't sell it here. Not that I believe that the ****el suffers from local boiling problems, but on the last strip down I was horrified by the corrosion and sludge that was there (OK the engine is well over 15 years old, but even so). But my longer term plans also include going to electric water pumps, but that's more a systems thing for my requirements for the car than an engineering necessity. Link to comment Share on other sites More sharing options...
Peter Carmichael Posted February 14, 2003 Share Posted February 14, 2003 OAT is supposed to be particularly bad for copper/brass radiators. You must have an ali radiator to use a pure OAT. Not sure about HOATs. Trying to find a definitive statement. Interesting snake oil ruling on this brand of propylene glycol coolant...legal report ...noting that most of the court ruling is for lack of substantiation of claims. Link to comment Share on other sites More sharing options...
Old Septimus Posted February 14, 2003 Share Posted February 14, 2003 If you don't have an aluminium engine or radiator and frost protection is not an object, is pure water the best option? Link to comment Share on other sites More sharing options...
Peter Carmichael Posted February 14, 2003 Share Posted February 14, 2003 Now I am getting to the bottom of it. It looks like the additive package for some of the propylene glycol based coolants uses the same organic acid technology. I have also read statements on how it works: 5. Heat Transfer Efficiency The carboxylic acid inhibitor forms a single layer of protective molecules on the metal surfaces thus providing a very efficient heat transfer. So it seems that my previous assertions about propylene glycol might well have been all about barking up the wrong tree 😳 The PG is just the anti-freeze agent (and not a particularly good one). The additives package is everything. This means that Comma XTreme Red (a HOAT based on Gysantin g05) will be a very good and acceptable choice. Link to comment Share on other sites More sharing options...
Peter Carmichael Posted February 14, 2003 Share Posted February 14, 2003 Pure water is very corrosive. For racing purposes, you can use water with some of the commercially available additives packages. There are OAT packages available for use with water on its own. Link to comment Share on other sites More sharing options...
elie boone Posted February 14, 2003 Share Posted February 14, 2003 This is weird, 3 pages about antifreeze but only in the last posting there is a mention of water. I use mono ethylene glycol but always with demineralized water because water from the tap is far to acid. Link to comment Share on other sites More sharing options...
Peter Carmichael Posted February 15, 2003 Share Posted February 15, 2003 Mostly it was a debate about the anti-corrosion properties of additives rather than the pro-corrosion properties of pretty much all variations of water. A lot of the coolants mentioned are premixed appropriately with deionised water. Link to comment Share on other sites More sharing options...
Pierre Gillet Posted February 16, 2003 Share Posted February 16, 2003 Still trying to find some credible litterature stating that OAT is really incompatible with copper/brass heaters and radiators. Link to comment Share on other sites More sharing options...
elie boone Posted February 16, 2003 Share Posted February 16, 2003 Peter, If you talk about antifreeze you also have to mention water because you simply can not separete the two from each other. Link to comment Share on other sites More sharing options...
Peter Carmichael Posted February 16, 2003 Share Posted February 16, 2003 Pierre The literature on the OATs that I have looked up shows high corrosion with soft solder, which is a common construction technique for copper/brass radiators. If there is any residual flux present then the coolant takes up chloride ions which are highly corrosive for the entire system. The recommendation not to use with copper/brass all seems to stem from this. If you know the construction technique used for your copper/brass radiator and you know it is not soft solder then you may be OK. I think that is the bottom of the matter. Elie, I don't give a stuff about water when I am using premixed coolants. For mixing your own, I entirely agree. The acidity of any water you use, however, is nothing compared to the acidity developed by the coolant in the course of its use, so it seems to hinge more on water softness/ demineralisation etc. and the recommendations of the coolant manufacturer. Most seem to prefer demineralised/deionised over pretty much anything else, although some North American manufacturers suggest the use of soft tap water (no good if you live in a hard water region). Link to comment Share on other sites More sharing options...
Pierre Gillet Posted February 16, 2003 Share Posted February 16, 2003 All right then Peter. Thanks. I have now a better understanding. My radiator/heater have been run for 5,5 years with a silicate additivated coolant. I have just replaced it by a new long life OAT EG-based coolant ( by the way fluorescent yellow is its colour). I would expect that the remaining flux has already been washed off by the old coolant, and that the circuit is now free of these nasty choride ions. Link to comment Share on other sites More sharing options...
Pierre Gillet Posted April 23, 2003 Share Posted April 23, 2003 You were right Peter, my 6 year old copper radiator is now leaking after 3 months of EG + OA ... many laps at the Bugatti circuit probably also helped ☹️ I have just ordered to Caterham an alloy radiator. Does new generation heater comes in alloy too? Pierre Link to comment Share on other sites More sharing options...
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