MattB Posted October 16, 2022 Share Posted October 16, 2022 My 9 month old Caterham built 420 has just had its radiator replaced by CC under warranty. I'd been monitoring it closely, having read this and other similar threads, and thought I'd got away with it, but it started leaking from both sides at just under 6000 miles.CC asked no questions once I said it was a radiator problem, and just booked it into their first available workshop slot.It appeared that the leaks were where the matrix tubes entered the side tanks, so I'm wondering if the mounting arrangement is too tight horizontally, leading to the tubes expanding into the immovable side tanks when hot and breaking their seal. Perhaps slackening off the bolts and elongating the bracket holes on one side and allowing the radiator to expand horizontally as a whole might lessen the chance of another leak?MattB Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted October 16, 2022 Member Share Posted October 16, 2022 Thanks for adding that experience.I don't think that anyone has previously suggested thermal expansion of an otherwise well-fitting radiator as the cause of failure. That's a very interesting idea.Did you ever check the fit in the brackets and the mechanical load from the hoses?Jonathan Link to comment Share on other sites More sharing options...
MattB Posted October 16, 2022 Share Posted October 16, 2022 The fit looked good, the bobbins didn't appear stressed or twisted, and the hoses didn't look to be pulling/pushing on the radiator. Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted October 16, 2022 Member Share Posted October 16, 2022 Thank youJonathan Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted October 16, 2022 Member Share Posted October 16, 2022 Link to comment Share on other sites More sharing options...
MattB Posted October 16, 2022 Share Posted October 16, 2022 Thanks Jonathan - you are the Turnimator ....MattB Link to comment Share on other sites More sharing options...
John Vine Posted October 16, 2022 Share Posted October 16, 2022 I note that the old design had much longer bobbins. These are the ones on my 2008 R400D: I don't know what effect (if any) that would have, but yours do seem quite short and squashed. Also, presumably your mounting bolts pass right through the bobbins? I could see that being a conduit for vibration.JV Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted October 16, 2022 Member Share Posted October 16, 2022 John: Are your bobbins made with a separate stud at each end?ThanksJonathan Link to comment Share on other sites More sharing options...
John Vine Posted October 16, 2022 Share Posted October 16, 2022 Indeed they are, Jonathan (which, of course, is what triggered my comment).JV Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted October 16, 2022 Member Share Posted October 16, 2022 ThanksJonathan Link to comment Share on other sites More sharing options...
ScottR400D Posted October 16, 2022 Share Posted October 16, 2022 All those bobbins should be two separate studs. No point otherwise. I'm sure the OPs will be. Then again, it's a CC built car, I wouldn't put anything past them. Link to comment Share on other sites More sharing options...
ScottR400D Posted October 16, 2022 Share Posted October 16, 2022 As an aside, and it may be a silly question, but if this was a design issue wouldn't CC have sorted it out, it's been going on for years? Though I guess the same question could be asked if it was just poor quality radiators. Link to comment Share on other sites More sharing options...
John Vine Posted October 17, 2022 Share Posted October 17, 2022 Re #36:Yes, I think you're right, but (according to the Assembly Guide) with one stud and one female thread: This looks like the bobbin in question.The description suggests that it was originally intended for the 485 exhaust, so using it as a rad mount looks like a bit of a bodge. I think it could do with a lot more rubber.JV Link to comment Share on other sites More sharing options...
ScottR400D Posted October 17, 2022 Share Posted October 17, 2022 1 stud and 1 female is OK, plenty of rubber mounts like that. It's effectively the same as one with 2 studs, you still have the separated rigid mounts. I agree that these mounts might benefit from a bigger rubber mount though I'm still far from convinced this just a vibration issue. Link to comment Share on other sites More sharing options...
Billy.Whizz Posted October 17, 2022 Share Posted October 17, 2022 #26, I've also just had a new rad fitted under warranty on my 17 month old 420R, I noticed it leaking from the top 3 tubes above the top hose, looked a bit like bottom picture at #30. Mileage when first noticed was around 3500, the service manager told me that it's a manufacturing problem and nothing to do with fitting. Link to comment Share on other sites More sharing options...
ScottR400D Posted October 17, 2022 Share Posted October 17, 2022 #40 I guess there's a chance that 'they would say that' though in this case I think it could well be true. Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now