7Up Posted August 18, 2021 Share Posted August 18, 2021 A big shout out to Radtec who made a replacement radiator for me and dispatched in <3 days! Great service and lots of great advice. My radiator started leaking this month (see photo) on a car built by CC Nov 2018. Radec see lots of radiator failures and for cars that stand for long periods of time, they recommend blue glycol as opposed to the CC standard orange coolant. The latter apparently can congeal when standing and encourages corrosion/failure at these points.Sharing the word! Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted August 18, 2021 Member Share Posted August 18, 2021 Thanks.That view has come up a few times before, but IIRC not with that explanation.The problem is that that choice of coolant might not be optimal for the engine rather than the radiator. (This concern isn't specifically about 420s.)https://www.lotus7.club/forum/techtalk/k-series-ally-radiatorsJonathan Link to comment Share on other sites More sharing options...
ScottR400D Posted August 18, 2021 Share Posted August 18, 2021 I'm not sure you can blame the failure on the coolant; that looks like the Motul Inugel that CC now recommend. They used to promote Comma Xtreme G30 which my car has had from new without issue. It was drained a couple of time during its first 5 years, and put back in, and it was replaced at 5 years. It looked perfect and there was no sign of any corrosion. Both makes are OAT coolants. The thing is that when I got my car the first 3 radiators all leaked when new. I gave up trying to get a good one from CC and had the third repaired myself and it's been fine since.I would suspect the rad quality well before the coolant. Link to comment Share on other sites More sharing options...
Area Representative Geoff Brown Posted August 20, 2021 Area Representative Share Posted August 20, 2021 As the car is factory built could it be that the radiator was stressed when fitted ?My home built R400 rad is still going strong after 8 years (thats done it!). Only because I realised that the installation on to the chassis required as little stress on the radiator as possible which considering all the constraints was not easy.I do not think that the coolant can be directly blamed for the failure. My car has run on the red OAT since build with no problems. Link to comment Share on other sites More sharing options...
ChrisC Posted August 20, 2021 Share Posted August 20, 2021 Couple of things to note, the bracket looks to have been bent to locate that rubber mount bolt, and the gap to the radiator and that bolt head looks increased. I think you have to be very careful fitting the new 420 design rad. I purchased slim spanners to hold that bolt while tightening.Did that have any effect on your rads life, I don't know, but if you ever hold the rad while the engine is running there is a lot of vibration and those rubber mounts have to earn their keep. The new design also has much smaller rubber mounts, so they are also under increased stress. Link to comment Share on other sites More sharing options...
Leadership Team 700newtons Posted August 20, 2021 Leadership Team Share Posted August 20, 2021 reply to #3How do you go about getting a radiator repaired? Any recommendations. I have noticed a dreaded pink blotch after the Anglesey track-day.I only shelled out for a new radiator last year.Simon Link to comment Share on other sites More sharing options...
Area Representative Geoff Brown Posted August 22, 2021 Area Representative Share Posted August 22, 2021 After carefully looking at the photo in #1 I would suggest that the culprits are the alignment of the sub bracket attached to the chassis to the integral angled bracket of the radiator. The state of the integral bracket suggests that there was some persuasion to get it to fit thus stressing the radiator edges.There is a fair amount of low resonance vibration from a Duratec - just watch the radiator & engine at tick over. So I would suggest as I stated earlier that the radiator was stressed on build. Prior to an unknown date the radiator was attached directly to right angled brackets top & bottom that were part of the chassis. Attachment to which was by four large rubber bushes. Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted August 22, 2021 Member Share Posted August 22, 2021 This sounds right to me.As above I'm not convinced by the composition of the coolant as being the cause because: 1 It doesn't seem to fit chemically. 2 We don't hear about leaks becoming more and more common over time. (But of course this is all anecdotal.)And apart from that I'd still optimise the coolant for the engine rather than the radiator.Geoff has made the point about the physical location of the radiator. It needs to be mechanically unstressed, and this might require bending the support brackets, enlarging some holes, and packing with washers. Persuade anything except the radiator.Jonathan Link to comment Share on other sites More sharing options...
7Up Posted August 22, 2021 Author Share Posted August 22, 2021 Thank-you Gents for the comments. Premier Power are fitting the new Radec tmr, I will point out the stress concerns on current. Iain Link to comment Share on other sites More sharing options...
John Vine Posted August 22, 2021 Share Posted August 22, 2021 I see the OP has an SV. Are those more prone to rad failures? (I was wondering whether the side mounting plates would tend to magnify any vibration.)For info, my 2008 R400D S3 suffered this rad leak mid-2009 (out of warranty):To their credit, CC replaced it FOC with the same part, and I've had no trouble at all since.JV Link to comment Share on other sites More sharing options...
ScottR400D Posted August 22, 2021 Share Posted August 22, 2021 Will anyone ever find out why it's so ******* easy to double post on here? Link to comment Share on other sites More sharing options...
ScottR400D Posted August 22, 2021 Share Posted August 22, 2021 John, I don't think there's any evidence to say the SV is any worse than the S3, and IMO it's the quality of the radiators that is the source of the problem. As I often relate, when I built my SV kit in 2015, my radiator and two replacements all leaked, similarly to yours, on fitting.I had one repaired by a specialist and it's been fine for over 6 years now. I still have one of the others, which I kept as a spare, having little confidence that the repaired one would last. Not even had it fixed yet! Link to comment Share on other sites More sharing options...
Wrightpayne Posted August 22, 2021 Share Posted August 22, 2021 I think radiator leaks on sevens is one of the most common issues I read about (anecdotally)It has been suggested the rigid nature of the bobbins is the cause, however, most tin top radiators are mounted directly to the body / plastics (along with air con rads and oil coolers) and it is only the hoses that absorb engine vibrations, which, in the case of diesels can be quite violent at tick over. Add to this the significantly higher mileage of a tin top (diesel or otherwise) and lack of failure, what is the issue on sevens? Link to comment Share on other sites More sharing options...
7Up Posted August 24, 2021 Author Share Posted August 24, 2021 Well the new one is on, with loads of shims! I will upload photos later Link to comment Share on other sites More sharing options...
7Up Posted August 25, 2021 Author Share Posted August 25, 2021 Here are photos, look at the amount of shims required! Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted August 25, 2021 Member Share Posted August 25, 2021 (I think)Jonathan Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted August 25, 2021 Member Share Posted August 25, 2021 Great photos to illustrate the problem. And the force that would be exerted on the radiator without that packing.Jonathan Link to comment Share on other sites More sharing options...
CtrMint Posted August 25, 2021 Share Posted August 25, 2021 When I built my kit I had an absolute nightmare with the radiator. In the end I sourced replacement bobbins from the following site. They worked a treat.https://www.polymax.co.uk/anti-vibration-rubber-mount/cylindrical-vibration-bobbin-mount/Handy datasheet here;https://www.polymax.co.uk/media/documents/AV_Mount_A.pdf Link to comment Share on other sites More sharing options...
raw Posted August 27, 2021 Share Posted August 27, 2021 Having suffered similar issues on a Radtec radiator post conversion from K series to Duratec, I came up with these flexible mounts to stop any chassis flex being transferred through to the radiator. They've been on for ~10 yrs, done a number of European trips and have no issues with leaks (and I use the pink/orange coolant). M8 stainless bolts inserted from the inside of an offcut of silicone hose.CheersAndrew Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted August 27, 2021 Member Share Posted August 27, 2021 Haven't seen anyone do that before. Very interesting.Apart from the alignment I'd guess that those are much less stiff than the bobbins.Have you done that on all of the mounts or only at the top?ThanksJonathan Link to comment Share on other sites More sharing options...
ChrisC Posted August 27, 2021 Share Posted August 27, 2021 I understand why the spacers have been added, the bolt supplied bottoms out in the small bobbin, but a shorter bolt is far more appropriate solution. The other problem experienced with S3 installations is the fan (front mounted now) touching the 7 grill, adding spacers would only make this worse. It seems S3 420 are getting new nose cones (as of kits supplied 2021), I am not sure it this is for fit, or increased oil cooler air flow, either way it doesn't address the expansion tank clearance issues experienced by some. Link to comment Share on other sites More sharing options...
raw Posted August 28, 2021 Share Posted August 28, 2021 JonathanReplaced all the mounts with these, much softer than the originals. Hoses help to keep any excess movement in check.CheersAndrew Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted August 28, 2021 Member Share Posted August 28, 2021 Thanks, Andrew.Jonathan Link to comment Share on other sites More sharing options...
CtrMint Posted August 29, 2021 Share Posted August 29, 2021 So I've been going through my 420R all weekend, all prep for the Taffia. I started at the back and worked forward. Guess what I found! I'm now in a mad rush to source another. Mine was replaced in 2019 at around 1500 miles, its now on 4600 give or take. Does anyone know the warranty period for this sort of part? Also are there any alternatives? Link to comment Share on other sites More sharing options...
Mrp Posted August 29, 2021 Share Posted August 29, 2021 Hi Mark, see 1st post Radtec I used them for the radiator on the 7 you saw me with super to deal with and quality products Mrp Link to comment Share on other sites More sharing options...
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