MattB Posted April 10 Share Posted April 10 Quote At the top of the rad I see yr2022wk38 - 300C004a My second radiator, same model but built yr2022wk36, started leaking in February after just less than 6k miles. The original unit also did just less than 6000 miles. I’ve just replaced it with a Radtec unit. I had a tuned mk3 MX5 with a 2.0l Duratec pretty much the same as my 420. I used red coolant in it from new for 15 years and never has an issue with a leaking radiator. MattB Link to comment Share on other sites More sharing options...
aerobod - near CYYC Posted April 10 Share Posted April 10 I've had red (Ford red OAT) coolant in my R400D for 11 years and 39,000km / 24,000 miles. It is stored for 6 months of the year without being started. Still on the original radiator, if not the original engine. Just switching to Ford yellow OAT with the new engine due to the Ford red being discontinued. 1 Link to comment Share on other sites More sharing options...
Ainsley Posted April 11 Share Posted April 11 As with any problem that takes time to be noticed and starts small, it not surprising there are lots of theory's, anecdotal reasons and solutions. Basically the leaks have nothing to do with the colour of the coolant, as there are a variety of colours being used with a variety of results. A leak is a hole / crack - that's either poor manufacturing or stress related. Given the radiator is shaken about quite a bit it and the chassis twists when jacking up and some of us build the car and some hose solutions are not perfect - its likely these, or a combination of, are probable causes. Link to comment Share on other sites More sharing options...
Ant2 Posted April 11 Share Posted April 11 10 hours ago, MattB said: My second radiator, same model but built yr2022wk36, started leaking in February after just less than 6k miles. The original unit also did just less than 6000 miles. I’ve just replaced it with a Radtec unit. I had a tuned mk3 MX5 with a 2.0l Duratec pretty much the same as my 420. I used red coolant in it from new for 15 years and never has an issue with a leaking radiator. MattB Well, I guarantee mine will leak as soon as the car warranty expires in 5 months :) Would you mind sending me the link to the replacement radtec you are all using so I have it on hand? Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted April 11 Member Share Posted April 11 1 hour ago, Ainsley said: Basically the leaks have nothing to do with the colour of the coolant, as there are a variety of colours being used with a variety of results. That's my current conclusion. But have you read Radtec's note on the subject? Jonathan PS: This would all be so much easier if the relevant knowledge wasn't scattered across so many threads. Link to comment Share on other sites More sharing options...
Ainsley Posted April 11 Share Posted April 11 No, I've not read Radtec's note - where is it ? Perhaps there should be a summary of issues and solutions curated and kept in the Technical guide section ? Its too easy for quality information / help to be lost as its spread about everywhere and when you search you get several threads, some of which are pages long. Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted April 11 Member Share Posted April 11 3 minutes ago, Ainsley said: No, I've not read Radtec's note - where is it ? which links to: https://www.radtec.co.uk/news/index/coolant-advisory Jonathan Link to comment Share on other sites More sharing options...
MattB Posted April 11 Share Posted April 11 Radtec haven’t updated their website, so this page doesn’t yet show the option of buying just the radiator: https://radtec.co.uk/shop/radiators/caterham/r300420r-road/ Just give them a call when you want to order one, as they also need to know the model number of your fan. Be aware that they don’t have them on the shelf. Mine took 6 weeks … MattB 1 Link to comment Share on other sites More sharing options...
aerobod - near CYYC Posted April 11 Share Posted April 11 Radtec should be specific over which blue coolant they recommend. Blue G48 which was the old BMW spec is slightly different to blue G11 old VW spec and quite different than Asian vehicle blue POAT spec. Link to comment Share on other sites More sharing options...
Handwheels Posted April 24 Author Share Posted April 24 Now I've removed my leaky rad I've had a closer looked at the mounting brackets - and I'm now thinking of ditching the silly Z brackets and welding a small tab on the bottom of the chassis-radiator bracket. This would be aligned with the mounting points on the radiator and set back enough to allow the use of significantly longer & slightly narrower bobbins. It would be possible to fit in 25mm dia. x 30mm bobbins instead of the existing 30mm dia. x 15mm ones. Unfortunately, I can't see a way of using longer bobbins at the bottom of the radiator, but I think it's a case of 'every little helps'! I wouldn't make any other modifications to the chassis-radiator bracket, so in theory I could remove the new tab and return to the factory set up if required. I'm also planning to follow the lead of others, and cut back the rigid top hose and use a straight connector to fit a section of silicone hose. I bought a silicone 620 top hose, as recommended, but at first glance it doesn't seem to align with the angled top hose connector on the radiator - so I'm looking at other silicone hose options. Also, once I've finally got a new radiator fitted I will never use the towing eye as a jacking point again!! The attached pics show the existing set-up and my bobbin bracket proposal. I'd welcome any comments on my plans 😁 Thanks for all the comments & advice I've already received Cheers, Richard Link to comment Share on other sites More sharing options...
Ainsley Posted April 25 Share Posted April 25 So a longer bobbin would flex more, that sounds like a solution that will help eliminate vibration further. I would perhaps fabricate a bracket that just replaced the Z bracket, not weld on a new tab. All you need is a Z with a longer horizontal section. You could fabricate one up out of mild steel with a vice as a prototype to see how it all fits together first. Rather than the pretty permanent welding option. Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted April 25 Member Share Posted April 25 What matters for those brackets is avoiding any load on the radiator as it's attached and tightened up. Mocking it up somehow or other is a good idea but after that it would be lighter and simpler to make a custom bracket with fewer fasteners. If it involves fabrication there are some very helpful, skilled and generous Members... IIUC you could use the existing bobbins by taking up the extra distance in the bracket rather than with a longer bobbin. Jonathan Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted April 25 Member Share Posted April 25 10 hours ago, Handwheels said: I'm also planning to follow the lead of others, and cut back the rigid top hose and use a straight connector to fit a section of silicone hose. I bought a silicone 620 top hose, as recommended, but at first glance it doesn't seem to align with the angled top hose connector on the radiator - so I'm looking at other silicone hose options. Photos, please. I don't understand either how many variants there are or how the hose exerts load on the hose stub of the radiator. Jonathan Link to comment Share on other sites More sharing options...
Ainsley Posted April 25 Share Posted April 25 The latest hose, as fitted to my 420R this year does not seem to exert any load on the Rad. Link to comment Share on other sites More sharing options...
StevehS3 Posted May 11 Share Posted May 11 I had the nose cone off my Sigma car and noticed the rubber bobbins seemed long. Are they the same as fitted to Duratec cars. Link to comment Share on other sites More sharing options...
KnifeySpoony Posted May 12 Share Posted May 12 FWIW here's what my grafted 620R hose looks like. Looks slightly bent but it's so flexible there isn't any load on the radiator. Link to comment Share on other sites More sharing options...
KnifeySpoony Posted May 12 Share Posted May 12 sorry for upside down pic Link to comment Share on other sites More sharing options...
KnifeySpoony Posted May 12 Share Posted May 12 Because of the bend in the hose, it does ride up over the catch can a bit. I thought that might make it harder to bleed but I had no issue. And because the hose is so much more flexible, I can actually just move it over to remove the catch can. Previously I had to suck out the oil, because the old hose trapped it. Link to comment Share on other sites More sharing options...
ScottR400D Posted May 12 Share Posted May 12 (edited) 1 hour ago, KnifeySpoony said: Because of the bend in the hose, it does ride up over the catch can a bit. I thought that might make it harder to bleed but I had no issue. And because the hose is so much more flexible, I can actually just move it over to remove the catch can. Previously I had to suck out the oil, because the old hose trapped it. To be honest that looks terrible. This is how the hose used to fit: Edited May 12 by ScottR400D Link to comment Share on other sites More sharing options...
KnifeySpoony Posted May 12 Share Posted May 12 (edited) It looks like you have a totally different radiator and different mounting setup. Also is your car an SV? Edited May 12 by KnifeySpoony Link to comment Share on other sites More sharing options...
KnifeySpoony Posted May 12 Share Posted May 12 Here is the standard setup with original hose. Link to comment Share on other sites More sharing options...
ScottR400D Posted May 12 Share Posted May 12 Just now, KnifeySpoony said: It looks like you have a different radiator and different mounting setup. Also is your car an SV? It’s an SV but that makes no difference. Yes the radiator is the one that the hose and all the assembly was designed for and was used with much less trouble (though quality was never good) for years. What you have is another CC money saving bodge. Change the radiator to keep stock levels down and use the ‘racing’ one but don’t redesign the hose just leave customers to bodge it up. Link to comment Share on other sites More sharing options...
KnifeySpoony Posted May 12 Share Posted May 12 (edited) Ah Ok, I thought you were criticizing my solution. You can the see OEM routing is bad and the hose is under some tension to make the bend back to radiator inlet. The inlet pipe is angled coming out of the rad, presumably to address this, but didn't work well. That combined with the super stiff hose and vibrations must be contributing to failures. Hence my silicone hose. Edited May 12 by KnifeySpoony Link to comment Share on other sites More sharing options...
ScottR400D Posted May 12 Share Posted May 12 2 minutes ago, KnifeySpoony said: Here is the standard setup with original hose. No that’s the bodge up. Original hose with ‘new’ badly fitting radiator. it looks equally as uncomfortable as yours and is almost certainly putting pressure in the radiator. Link to comment Share on other sites More sharing options...
ScottR400D Posted May 12 Share Posted May 12 1 minute ago, KnifeySpoony said: Ah Ok, I thought you were criticizing my solution. You can the see OEM routing is bad and the hose is under some tension to make the bend back to radiator inlet. The inlet pipe is angled coming out of the rad, presumably to address this, but didn't work well. That combined with the super stiff hose and vibrations must be contributing to failures. Hence my silicone hose. It’s just typical, poor CC ‘engineering’ with the usual disregard for its customers. There is a lot of history about this ‘development’, most of it bad. Failing radiators, noses that wouldn’t fit, ugly looking installations, Radtech must have done brilliantly from it all! Link to comment Share on other sites More sharing options...
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