Ok who knows what the flat radiator does under the front of the Hiace. Put a digital temp gauge on the campervan as new head so dont want to take any chance. Today on its first 65 mile test drive I noticed the temp was around 90-94 deg. You can see the temp drop by 4-5 deg when the thermostat opens. On a long uphill stretch I noticed the temp went up to 98 deg, I quickly put all heaters on to cool the engine and eased off the gas. Is this ok to go that high?? I'm also wondering what the 2nd radiator is for under the front of the van, is this also part of the cooling system? It has a big electric fan on the top and I'm wondering if it's not cutting in. If anyone can shine any light on this subject I would be grateful. Cheers