The drive to and from the IVA test centre has thrown up a few issues with my car, and a warning for all S3 420 kit builders.

I knew driving to the IVA wasn’t without risk; driving a car I had barely driven a few meters for the first time a 200 mile round trip took confidence. I can only suggest builders do the PBC before driving to IVA.

The number one problem on the drive was vibration, felt through the seat, not the steering wheel. A horrid vibration that built from 50 mph and this limited my speed during the drive to and from the IVA test.

On return I had all the wheels rebalanced, during the wait for the registration, but the problem persisted. In the end I asked Caterham to look at the problem during PBC, but I had already observed a “non round” tyre. The tyre was replaced during PBC, which massively improved the vibration, but it’s not 100% eliminated. My next course of action will be a road force tyre balance to eliminate further tyre problems once and for all.

The big and really annoying problem is the expansion tank dented the nose cone. Even after all my efforts to find space for the expansion tank cap and the noise cone. The damage wasn’t evident during the IVA test, it occurred on the way home from the test.

I have studied the photos I took of a 420R S3 and had a eureka moment. Caterham must be modifying the expansion tank.

From the photos you can see the fluid level is level, where as you can see my fluid level is not. This must mean they are removing some of the plastic at the bottom of the expansion tank. This would lower the expansion tank cap, and prevent nose cone damage.

Why this isn’t mentioned in the old or new build manual I will never know.

Obviously the nose cone is an expensive item, but Caterham have been wonderful in their response to my complaint about not being informed about the need to modify the expansion tank. They wanted to attempt a repair first, but always with the proviso that if wasn’t to my satisfied it would be replaced. The nose cone was returned to the factory for a few days, and the good news is that the repair has been 100% successful.

Caterham advised the expansion tank can expand when very hot, and this makes sens,e because on the return from the IVA I did get stuck in some heavy traffic and it was a hot day.

With that said, I needed to insure this would happen again.

To be continued. (Expansion Tank (Revisited))