Bongo Fury

So here goes, my first foray into Bongo life. So I have a P ref Bongo with no service history. It’s been converted to 2 wheel drive, I can see the head has been off, the usual temp, water and oil additional sensors/alarms have been fitted, diesel heater, welding been done, new rad and coolant caps, new exhaust bits and bobs, it’s been loved. I want to love it and learn as I go. It’s overheating, I’ve bled the system, twice, changed the stat last weekend, managed to get it open and take for a run. The temp gage rose rapidly during climbs and then, as rapidly sorted itself out, so I thought I’d had a win, only to find this weekend I’m back to square one with an overheating vehicle and despite leveling all coolant during another bleed, that under load the header tank fills to the brim and temp rises to maximum…..have heat through front matrix but not rear, any ideas on what I could try next? Any gentle advice to a true amateur in every sense much appreciated. I’m in bexhill-on-sea, East Sussex thank you.

Welcome aboard!

Sorry to hear about the overheating Most frequent cause is an air lock is causing the coolant flow to stop and hence the overheat, if there are no signs of a coolant leak (the system is a pressurised system!) then another reason can be a a small pin hole leak that ejects coolant under pressure, it then draws in air once the system cools down again, this sometimes needs several heating/cooling cycles to get sufficient air in to cause an air lock and then an overheat - be aware to many of these or a sever overheat WILL crack the head!! You can try a UV dye in the coolant and then search for the spray and tell-tale mark with the UV torch (see eBay for kits - https://www.ebay.co.uk/sch/i.html?_from ... +kit+torch ) another method that sometimes works is whilst the weather is cool in the evenings take it for a drive or get it up to temperature/pressure and then with a pencil beam torch inspect the engine area for condensing steam traces from the coolant squirting out from a hose/pipe.

The lack of rear heating may well be that the rear heater has been bypassed in the past due to a leaking pipe or heating matrix. Check the pipes that go to the rear heater behind and underneath the drivers side. Two pipes are the Air con refrigerant and the other two are the coolant pipes back to the engine itself.

Two thoughts......has the Bongo been stored for an extended period, ie months with starting the engine?? Are you trying to bleed the system by yourself?

I found that if the vehicle is stored for long periods, the pressurised coolant system equalises to atmospheric pressure and then coolant slowly leaks from around the pump, which is very hard to spot, but if left long enough and a fair amount of coolant leaks (circa 1l), the level drops and an airlock is then created when topping up.

Also, if trying to bleed the coolant system by yourself....that is only possible with a really big faff; thinking things through and also finding some way of holding the top bleed hose high during the procedure, but it's far easier and quicker as a two-man job. The bleeding procedure needs to be followed to the letter and if in any doubt, repeated many times.

The stock temp gauge is rubbish, just not sensitive enough, so gives a very late overheat warning, but if you caught your events early and immediately stopped the engine then should be fine. An airlock does not sort itself out. If you soldiered on, especially on a long climb, then I'd fear the worst, but you may be lucky.

Have you checked out the you tube videos on the bleed process?

A quick Google brings them up.

Thank you so much for reply’s, I have bled the system using the seesaw method shown via the YouTube videos, several times with my dad, so I think I’ve been cautious enough. First time around just couldn’t get the bottom hose hot, was able to after the stat change. I’ll check for leaks next, and the rear hoses. My feeling is that some air may well be getting in constantly somehow, the van hadn’t been standing, was being used and I drove it back after buying it for 1.5 hours no problem, super frustrating! My next port of call was change fan and bottom house and flush rad. May try this if I can’t identify any leaks. Thank you. Will report back.