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Major issues - radiator & Oil cooler !

As I’ve mentioned before I’ve faced a number of significant problems during the build which not only impacted the build itself, but also my motivation to blog. I became extremely frustrated by the whole experience and found continuing the blog too difficult and so stopped, however some build progress was still made in the background and so a number of blog posts are going to appear as retrospective posts and which are most likely out of sequence. That said I will do my best to ensure any build dependencies are stated.

Before we look at the specifics I’d like to take time to comment on my feelings towards the car as a purchase. At this point in time I deeply regret investing in the product, simple as that. The truth of the matter is that Caterham Cars cut significant corners in terms of quality and finish yet charge top money for their product. I have spoken to Caterham Cars about this view and they in my opinion hide behind the statement that they are too small to deal with the issues. I personally don’t accept this view. Additionally I’m a member of the Lotus 7 Club and forum through which I’ve discovered my view is pretty familiar to the point many members feel quality is rapidly deteriorating.

It is possible I should have performed more research before making my purchase to discover how low the quality aspect is, and for this reason I would recommend all future potential purchasers heed my warning. Double check you are happy with the quality above all else, don’t make my mistake.

At the moment a number of my issues remain unresolved and so I’ll likely follow up with additional posts on how these matters progress.

So where did things start to go wrong? I can confidently state with the radiator and engine bay plumbing. The kit I was provided is a shambles of ill fitting parts, and even now as I write this blog the matter remains unresolved with Caterham Cars.

All Duratec cars are fitted with oil coolers, the 420 particularly has the largest which is fitted at the from of the car. Historically the oil cooler has been a separate unit mounted just in front of the radiator, however at some point this year Caterham claim they took the decision to swap the radiator design for 420 road cars to the ‘race’ specification radiator which includes an smaller radiator core and an integrated oil cooler. I say claim as I’m still trying to find a similar car for sale!

On paper the above change would appear to be a good idea and one which should simplify fitment. Unfortunately Caterham Cars did not perform adequate quality control and as a result released the revised product with significant design flaws.

These flaws include.

  • Mounting bolts are an incorrect size.

  • Mounting bobbin fouls against radiator top hose.

  • Radiator top hose is an incorrect shape.

  • Radiator top hose prevents access to catch can when fitted.

  • Radiator sits too high and fouls against nose cone when fitted.

Let’s discuss each item…..

The radiator uses an integrated aluminium bracket which is welded onto the radiator itself. Bolts are integrated into the bracket, however you can’t remove the bolts once the bracket is attached due to the radiator being at the rear. Unfortunately the bolts fitted are too long and as a result significant spacing occurs between the radiator and mounting bobbin when the radiator is hung. When I raised the matter with Caterham Cars I was instructed to cut the bolts down to fit. Not ideal since you have to cut the bolts whilst still on the radiator.

Once you’ve cut the bolts down you can then mount the radiator using the bobbins provided. Three of the bobbins fit fine, however the fourth, top near side bobbin is next to the top hose port on the radiator where the top hose fits. The proximity of the bobbin to the hose port prevents the hose from being fitted such that a jubilee can’t be appropriately installed.

Inadequate clearance prevents hose fitment and clamping

Hose removed illustrating lack of clamping space

Again Caterham Cars are aware of this and I was told to cut the bobbin down to provide clearance. The bobbin is made from rubber with an outer metal plate which provides structural support. Doing as they stated would have looked terrible and significantly weakened the device. I refused to accept this disgraceful approach and complained bitterly, unfortunately Caterham Cars were not receptive to the situation. Ultimately I’ve been forced to source a replacement bobbin myself, one which has the correct height but a reduced diameter providing the much needed clearance and maintaining the structural integrity of the part.

Replacement bobbin fitted

Original bobbin (left) Replacement bobbin (right)

Replacement bobbin Details are below.

Polymax Article No. B2015M820-1.5

I approached Caterham Cars regarding the replacement bobbin suggesting they add the unit to the kit, unfortunately they declined stating they couldn’t assess or warranty the part. A comment I find difficult to understand since they are prepared to warranty a modified part.

A second issue with the top hose is that it is shaped for the original radiator design where the top hose connection is roughly in the middle of the car. Given the revised radiator has the hose port on the near side of the car you are required to bend the hose around to fit. Unfortunately the hose is of sufficient thickness and subsequent strength that the entire hose structure moves across when forced to fit. Doing so results in the hose catching against the outer edge of the car including the nose cone catch, and will therefore likely cause premature wear of both parts. Caterham’s fix here is to use cable ties to force the structure into the desired shape. I feel a correctly shaped coolant hose should have been provided with the revised radiator, but sadly Caterham Cars refused. I have looked into sourcing alternatives myself and will update if I do.

Once the hose has been forced into place it unfortunately sits over the top of the oil catch can fitted to the chassis side. Whilst not a huge issue it will mean that removing and servicing the catch can will require draining and removing the top hose. Catch cans typically need to be drained more frequently than coolant changes, and so this represents another short sighted design issue.

Catch can interference from top coolant hose after bending around to top hose port

One of the most notable and critically outstanding issue is that the revised radiator does not fit under the nose cone. The radiator is too high in reference to the nose cone and rubs against the fibre glass. Caterham Cars have suggested modifying the chassis to force fitment, a solution I have refused and will continue to refuse, however the matter currently remains unresolved. Whilst tackling this issue I’ve received support from the Lotus 7 Club forum and as a result been made aware of an alternative nose cone design used by the 420 race car which might account for the extra height needed to clear the nose cone. Caterham Cars don’t feel this is a requirement, but as mentioned the matter remains unresolved.

Tope right and left of radiator rubs on nose cone, also makes fitting the nose cone near impossible

I’ve also experienced issues with the oil cooler lines, but will discuss those in another post.

In summary all of the above issues remain with the exception of the bobbin which I resolved myself through sourcing an alternative part. The experience has been extremely disappointing and continues to be whilst unresolved.

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