A small imported camper van came to WMM with a problem that was interesting for us to solve but infuriating for the van’s owner. They had planned to tour Europe, but had lost confidence in the vehicle.
Occasionally the bonnet felt hot and at other times there were absolutely no problems whatsoever. Also, the temperature gauge went higher than normal and there was also a small loss of coolant.
The customer was worried that this could be the cylinder head gasket. We thought this was unlikely.
Whenever we diagnose a fault, WMM director Dave always tells our technicians to start with the simple things first and eliminate the obvious.
We decided to carry out a simple coolant pressure test first, as this test is inexpensive, and would show if there was a leak on the system.
Inspecting the vehicle, we noticed that the radiator cap did not sit correctly. Removing the cap showed a poor base – at this point we abandoned the pressure test – and the radiator cap seal was damaged.
When the vehicle's cooling system was at operating temperature, coolant under pressure was coming out of the radiator and hitting the bonnet.
Ideally, a new radiator was required, but this would have been an expensive repair so we carefully cleaned the housing and renewed the radiator cap.
This solved the problem. WMM ran the vehicle to temperature and the bonnet was no longer hot.
The customer was extremely pleased as the invoice was far less than expected.