Choice of radiators 13/07/2017 and updated 22/12/2020
| Choice of radiator The original article on radiators about heat conductivity, fin design, core, tube sizes, plus design changes with all latest market findings and trends become a thesis, which I then realised was fairly irrelevant, or of no use to most Mini owners who only have a few options or requirements. Original Brass and Copper or Aluminium. See list at bottom of page. If you enter any of the following headings in google you can update yourself on technology. Aluminum Versus Copper Brass radiators. What makes the better radiator- Aluminum or Copper/brass radiators, or Cuprobraze based on the CuNiSnP system (latest radiator technology) For the mini owner you are stuck with the original side mounted 10.5” to 11” square radiator from 1959-to 1996, or front mounted as per the MPI. So, to make choice easy—for originality, fit the Copper fins on brass tubes type radiators always painted black to stop corrosion. The original buzz word in the late 60S was use a radiator with 16 gills(fins) per inch but this is completely outdated now by technical and manufacturing advances. If you have an original embossed Coventry Radiator’s top tank or MK1 with the top hose outlet at the end of the top tank-try getting it re-cored. From the MK2 on they moved the top hose outlet inwards about 1.5” to help reinforce it from breakage/cracking through vibration, especially via the old hoses when they became rigid. There are other factors to take into account to help decide which is the most suitable radiator for your mini as there has been so many changes in radiator caps and thermostats- the first centigrade thermostats were mainly 74c known for summer use, 82c for winter use which then became all year round use on all A plus engines 1980 on, then 88c from 1990 on to make the engine thermally efficient— GTS102 74c GTS104 82c GTS106 88c 11G176 blanking sleeve to reduce engine temp on 3/4 cylinder but by pass hose requires blanking off. The first radiators used a 7lb cap with a 33.6mm tall spring neck which was then replaced by the current height of about 27.5mm tall for the rest unless mentioned. Some Cooper cars had 10lb and then 13lb became the standard until 1990’s when Rover fitted a15lb radiator cap plus an electric fan as standard on 1275cc engines. GRC101 7lb early long 33.6mm neck cap GRC102 7lb short neck 27.5mm long cap GRC111 13lb short neck cap to1980 GRC110 15lb short neck A plus engines without expansion tank GRC207 16lb for radiators with sender unit and expansion tank 1991-96 GRC126 for expansion tanks no pressure spring. GRC1184 screw on rad cap for MPI expansion tank only 1996 on. I would always recommend fitting an electric fan to any Mini which might run hot at any time, as you do not want your engine running to hot or to cool. Likewise never fit an oil cooler to a road car without an oil thermostat for the same reason. Higher the pressure cap poundage, the hotter the coolant has to get to boil. A 15lb cap fitted as standard from 1990 is sufficient as Engines normally work best and more thermally efficient at 180-210 Fahrenheit owing to enforced pollution laws, oil and petrol now available. Having too much pressure in the system can result in damage and to little can cause overheating. Remember anti freeze also makes the engine run hotter! Mini values have increased so dramatically many owners only want to keep their cherished possession in an original standard condition without an electronic fan which is usually fine on standard engines especially 850/998cc. My standard rebuilt Cooper S Mk3 has a 2 core with 13lb cap on the original Coventry header tank and it runs too cool in winter with 82c thermostat and only gets to correct temperature on hot days with normal driving. I only use the car in summer so that’s perfect but all engines run different. Copper fins on brass Tubes as original. For standard engines ARP2000 and GRD172 are sufficient with the later only being different in that it has the twist in temperature sender unit facility for 1275 cars with electronic fans from 1991 on. Both these radiators have 3 offset rows of thin tubes where manufacturers found out thin tubes broke the coolant down into smaller amounts which further improved cooling by lighter material used and heat transfer. Just to confuse everybody in 2020 Mini Spares introduced the first cuprobraze latest technology 2 core alloy radiator ARP1110 looking externally identical to the ARP2000 for standard fitment use, painted black to look original and cover any blemishes from preparation and manufacturing it is the cheapest top quality alloy radiator available and has had rave reviews from race and road users alike for keeping engines at correct temperature. Advantages of this radiator are-it is greener for the environment and cheaper to produce, better thermal performance, corrosion resistance, strength and durability. ARP2000/GRD172 picture Always try to fit an electric fan if you feel that your car runs to hot in the summer. I have been watching radiator design improvements all my life as most of my 1960 to early 70’s tuned cars with high compression ratios and original radiators overheated, especially my 970cc “S” and 8 port well tuned engines. Most modern day cars have an engine coolant temperature of around 90 degrees with the engine oil temperature similar or well above and with the specialist oils they are able to run on much lower oil pressures unlike the mini which absorbs power and lowers BHP-so beware-running your engine to cool causes premature piston and crank bearing wear. In 1978 mini Spares introducedC-ARA4444 known as the 4 core which has 4 rows of offset tubes and 12% larger fluid capacity which was the best radiator available until 1991 when the 2 core with 2 inline rows of tubes was introduced. The C-ARA4442 radiator has the superior cooling V shape fins but can clog up in certain conditions such as Grass track or autocross racing whereas the flat finned 4 core does not and can be cleaned by water hose easier. Therefore the 4 core still has its place in Minis such as the Clubman where there is a greater area for air to move around or hot climates where greater water capacity is required when using overflow/expansion tanks. The 2 core C-ARA4442 is very intricate with the largest brass tube sizes possible without loosing strength or increasing weight and still remains the mini owners favourite for tuned road and race engines albeit in 2014 we found a close contender-namely ARP1106 with 3 inline rows of tubes and V type fins which seems slightly better on some engines by holding radiator pressure on tick over or when the engine is switched off which Historic racers prefer when changing drivers. ARP1106 is slightly cheaper but has no drain plug or screw in sender facility, but any future demands could implement a design change but that will cost us at least £10.50 +vat extra. C-ARA4442 ARP-1106 picture Aluminum-Bright and beautiful If you are not worried about keeping your Mini original looking and want a lightweight/ bright looking or super cooling radiator then aluminum is the answer. The C-ARA5000 is the lightest radiator with V shape fins and 2 rows of inline tubes with about 25-30% more “cooling area” than the standard cores of ARP2000/GRD172 type. It has shown up to 10% better cooling than a 4 core when racing in USA. C-ARA5000 picture Copper fins have about 70% more heat conductivity than the aluminium fins but the copper type have solder that the brass tubes require which acts as a thermal barrier, hence the all brazed aluminium with larger tubes cool much better so we introduced the ARP1110 cuprobraze latest technology radiator, as mentioned at the start of the article. Mini Spares C-ARA5000 was designed after seeing the original ugly ill-fitting cheap imports from China and those with 8 lug nuts welded on the side for the cowling. These fabricated alloy radiators started life by someone as a copy hopefully of our original 2 core radiator. Mini Spares gave the design to a UK company who then set about getting the top tank smaller and sides as original to fit the radiator cowlings properly. The last part was to put a drain plug with same thread to accept our screw in sensor and position the bottom hose outlet in the correct position to fit the Cooper S plus all other minis, similar to all our radiators. As stated before –make sure your engine runs warm enough for both oil and water temperatures but if nothing else has suited your cooling then we have C-ARA4441, the core is 42mm thick with 23 rows of single tubes within the main 42mm x 3mm water tube and 24 rows of 8mm external louvered fins, the core is fully vacuum brazed for durability with V section fins and is the best off the shelf UK made radiator available. Even this was not enough for our Mini Sprint with 1460cc and 8 port fuel injection but they were able to make an off the shelf 68mm thick core special and coupled with an overflow tank and this done the trick. C-ARA4441 picture When changing to an alloy radiator always ensure every part of cooling system is drained down and thoroughly cleansed as they are more prone to suffer from galvanic corrosion. Galvanic corrosion can occur with any electrical faults such as your choke cable becoming your earth wire owing to bad battery connection or early positive earth cars causing any engine and coolant metals to react. Modern day cars are designed for aluminum parts, reducing the risk of galvanic corrosion so when fitting aluminum radiators or other parts to classic minis with cast iron blocks always check electrics and earths, “flush and change” antifreeze regularly as instructed with ethylene glycol, generally a 1/3rd mix is good down to -19c and a 50/50 mix as now often recommended by manufacturers which helps break down contaminates with its chemical additives and is good down to -36c. ALWAYS USE DISTILLED WATER ONLY. Our GS119890 Mini Spares Opticool Antifreeze Blue is a universal engine coolant, suitable for all year round usage. Opticool Antifreeze Blue is manufactured from pure monoethylene glycol, anti-corrosion additives and inhibitors. It has been specially formulated to be truly universal in its application. It provides a high degree of corrosion protection for all engine cooling systems whether they are predominantly of aluminium or ferrous construction. Opticool Antifreeze Blue employs established inhibitor technology and is nitrite, amine and phosphate (NAP) free and includes borate and silicate, plus a bittering agent to prevent accidental consumption. IMPORTANT NOTE-Reducing anti freeze levels in summer will help cooling as it absorbs heat about half as much as water. Aluminium radiators usually last longer in cars designed for them than Copper brass types but regular “flush and change” is required in Minis. |
| ARP2000 Copper/Brass | GRD172 copper/brass | ARP1106 Copper/brass | C-ARA4442 Copper/brass | C-ARA4444 Copper/brass | C-ARA5000 Alloy | C-ARA4441 Alloy | ARP1110 Alloy | ||
| Capacity in Pints | 2.11 | 2.11 | 2.55 | 2.29 | 3.17 | 2.55 | 2.38 | 2.11 | |
| Capacity in Litres | 1.2 | 1.2 | 1.45 | 1.3 | 1.8 | 1.45 | 1.35 | 1.2 | |
| Tube Positions | 3 offset | 3 offset | 3 inline | 2 inline | 4 offset | 2 inline | 1 row | 2 inline | |
| Tube Rows | 19/18/19 | 19/18/19 | 25 | 27 | 21/20/21/20 | 25 | 23 | 25 | |
| Tube Size | 13×1.9mm | 13×1.9mm | 12.2×2.57mm | 19×2.2mm | 13.5×2.2mm | 22x2mm | 42x3mm | 18x2mm | |
| Tube Size Total | 24.7 | 24.7 | 31.35 | 41.8 | 29.71 | 44 | 42 | 36 | |
| Tube Gap | 1/2″ | 1/2″ | 3/8″ | 3/8″ | 1/2″ | 3/8″ | 3/8″8mm | 3/8″10mm | |
| Shape of Gills | Dead Flat | Dead Flat | V shape | V shape | Flat Louvered | V shape | V shape | V shape | |
| Gills per inch | 9 | 9 | 8 | 10 | 14 | 8 | 10 | 10 | |
| Core Depth | 44mm | 44mm | 47mm | 43mm | 55mm | 50mm | 42mm | 42mm | |
| Frame Depth | 45m | 45mm | 50-52mm | 48mm | 62mm | 60mm | 60mm | 45mm | |
| Weight | 2.28kg | 2.35kg | 3.08kg | 2.71kg | 3.27kg | 2.1kg | 2.38kg | 2.02kg |
GRD974 MPI front mounted radiator from 1996 capacity was 1.06 pints (0.06 litres)