What's in the issue

In an internal combustion engine keeping oil and coolant from mixing, or oil and coolant from escaping, there’s usually a gasket or seal helping. When these components fail, some (but not all) need a sealant to help them seal. But which sealant do you use and why? We find out! Plus, our project Aygo gets a front suspension refresh; we service a ZF 8-speed automatic gearbox; look at buying a Citroën C4 Cactus; repair a Ford Ka front bumper dent on a budget; probe diagnostically a Nissan Qashqai 1.6 dCi and review the Steelman Pro Wireless ChassisEAR 2.