The Mighty Bongo uses the same 2.5 Diesel engine from the Ford Ranger, and while strong and good for many miles, due to the setup including the rear heater, air can get trapped causing overheating which generally leads to a cracked head and a big bill. I previously found this out the hard way and don’t want it again.
The temperature gauge on the van is notoriously poor, showing no change in the needle from 90-110/120 degrees C, after this it rockets up and is often too late. It’s recommended to fit a coolant alarm (I haven’t yet done this!) So while driving recently, the temperature would raise passed operating temperature and then drop again when driven. I assumed trapped air, better to be safe than sorry, so time to bleed (more on this in a future post)
Following the bleed and a number of miles I checked the header tank. Empty! Here we go again!
While there are no obvious leaks I thought the best route would be to pressure test the system, to see if it is a small leak, or just the last of some trapped air.
After a swift purchase of an 18 piece pressure testing kit, I was hooked up and ready to go. Its fairly simple on the Bongo, a replacement header tank cap and a small hand pump attached and pressure it up to 12psi.
After leaving the system for 20 minutes it had lost around 1.5 psi, which from scouring the internet is acceptable. I also found that its normal to have to top up the header tank after bleeding the coolant.
There hasn’t been any overheating issues or movement in the temperature gauge but something else to keep an eye on!
