420R (S3) Radiator design issue, regular failures???

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Blue7
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Given that we now have a new relationship with CC, can someone in the MT contact CC with the above evidence and request an official response?  There only appears to be three possible causes of the problem, poor quality radiators, confirmation that they are only designed to last 2k miles or bad design of the adaptor brackets.

I am now of an age that too much stress just increases blood pressure so I would take the "easy" way out and grind / file down the brackets.

7 wonders of th...
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I was at Alicool yesrterday to collect a fan for my new 60mm rad, speaking to Keith the owner, I mentioned the problems with current 420 rads and he openly talked about why he set up Alicool.

He and 2 others started Radtec, all was well until the other partners wanted to cut cost by buying cores from the far east, Keith objected and during prolonged heated exchanges he decided this wasn't the route for him sold his share and set up his own business.

I mentioned Radtec's claims that using the wrong coolant is causing the failures, he said his rads are fine with any coolant no problem, the problem isn't the coolant but the cheap cores.... he wasn't shocked by the repeated failures at very low mileages either.

If you get no joy with CC might be worth you having a chat with him about making a batch up, I agree that a 2 piece rad / cooler design would be more cost effective for owners to.

There must be more that one failed unit out there to use as a pattern.

ScottR400D
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I'd buy a rad to the old spec from Radtec, get an oil cooler from Mocal (CC have them in stock as well, £75) and revert to the old specification, which works well and has none of the issues we're seeing here. (Other than the quality of the original rads).

It looks like CC have all the other bits that might be needed in stock too. 


 

L7C
John Vine
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Re #43: Very interesting, Neil -- makes complete sense.  I never did buy the "blame the coolant" notion, and I'd always choose the coolant the engine warrants.

Re #44: I think that's very good advice, provided the rad is of good quality.  That set-up is what I have on my 2008 S3 R400D (except that mine is wet-sump, so I have a sandwich plate on the filter housing and two long oil hoses), and has performed flawlessly for 12 years now. 

APIWATW (from the Assembly Guide):

JV

ChrisC
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If you choose this route, don't forget to also factory a smaller cooling fan, mounting brackets for the cooling fan and different length oil lines for the oil cooler.  

ScottR400D
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#45 Once I had the radiator, which leaked from day 1, fixed, mine too has been faultless. 

#46 Yes, of course, a fair point. 

L7C
ChrisC
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From Caterham Parts website, about £742

Radiator, Oil cooler, oil cooler brackets x2 , oil cooler lines x 2, cooling fan, cooling fan brackets x2, bobbins x 4

StevehS3
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#43 I recently changed my plastic topped, crimp sealed CC rad for Alicool. Having read the BC thread about coolant I raised this with Alicool. As per #43, they informed me to use the correct one for the engine and what is recommended by CC. It appears to be a very solid core and extremely well made but time will tell I suppose. 

CtrMint
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I'm making appropriate progress with CC, I've now a _chance_ of getting the 420R back on the road in time for the Taffia.  We've had a productive conversation, and while we don't have agreement with respect to the design, I am happy that CC are listening and being very respectful and responsive to my point of view.  I really can't fault them for that.

I've also had a long think about my view of the car, particularly how anal I am with detailing and keeping it mint (check my Instagram).  After considering the potential life span over the next 10 years max, and that i won't sell it with any meaningful value, I've decided to start modifying the car, something I really wanted to avoid, I wanted to ensure it remained 'factory' at all costs.  That view seems to conflict with the practicalities of ownership, and if I'm going get the max from my ownership, I should just accept mods are needed.

Thus I've been up to Screwfix and purchased a new Dremel and various cutting disks, I'm going to carefully cut the corner off the mount where the contact occurs.   I know many of you suggested this, but it just wasn't something I was prepared to do until now.

PS, before someone says it, I do have a grinder, but its a bit of a dangerous weapon in my hands, a dremel is more me ;-)

Caterham 420R S3 Lotus Toxic Green,  Caterham 620R S3 Exocet Red. Blog: https://www.caterham7diaries.com
TomB
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It’s a kit car at the end if the day, some modifying with an angle grinder should never be ruled out!