Bongo Fury

Hi All,
Bongo developed some overheating issues Last Sunday
If you can share some opinion it will be great.

At one point when I was driving it the temp gauge was showing a bit high temp. I started the heater and it was not blowing really hot ear.
After 5 mins the heater stopped producing any heat. At that moment I stopped the car and checked the lower radiator hose which was cold.
And from the expansion tank colorant was dripping.
Obliviously I had to bleed it and top up with about 2 liters of water.
After that everything was fine for the rest of my journey - about 45 mins. The lower radiator hose was hot, the heater worked ok and the engine temp was normal.
The next day checked the coolant level - it was dropped with 2-3 cm which I believe is not a good sign.
Top it up and started the engine. after 10-15 mins the heater also stopped producing any heat the lower radiator hose was cold.
Again bleeding and for the rest of the journey temp/heater was ok. Got home without any issues.
Next day I decided to do a bleeding from a competently cold engine.
The weird thing is that a lot of bubbles started coming while the previous journey was ok.
When the engine got hot bubbles were not appearing anymore.

I think these can be the wrong bits with the engine:
1. Faulty thermostat which cannot open every time - i will remove it this weekend and see how the engine will perform.
2. Head gasket gone - pushing some exhaust gases into the coolant circuit.
3. Cylinder head cracked - pushing some exhaust gases into the coolant circuit.

Point 2 will be expensive to fix. I can see in ebay you can bay a gasket kit for about 60 and head skimmed+pressure test is about 100
But if it is cracked than a new one /complete/ is about 300 + the gasket another 60.

this bongo has 210 000 km /130 000 miles/. I dont have history if the gasket cylinder head have been changed before. But the engine still sound really good.
The engine oil still looks good - no yellow stuff or weird viscosity
I was not able to find/locate any coolant leak. but that one can be a tricky as it evaporates really fast if the leak is a small one.

Do you think if I buy something like this and if there is a leak to the coolant circuit I will be able to catch it.
BT-3 BLOCK COMBUSTION LEAK TESTER KIT CO2 BLOCK HEAD GASKET TEST FLUID 35d
https://www.ebay.co.uk/itm/BT-3-BLOCK-C ... 2514603676

thnx

After bleeding it’s normal for the level in the header tank to drop 2/3 cms...
Even in normal use it will drop 2cms from hot to being cold...normal expansion
Do you have a low coolant alarm fitted?
Do you have a digital temp gauge fitted as the one in the dash is pretty useless.

i have them but not mounted yet. as i have two bongos now I am still wondering which one to keep.
but my question is what can cause the overheating issue and why the heaters stop blowing hot air.
bad thermostat or head/gasket gone

This looks like loss of coolant, that would cause the heaters to stop working as there would be no hot water going through them.

If you had to top up 2 ltrs I would say there is a leak which needs fixing first, maybe a pressure test will find it, and a 'sniffer test' to see if there is combustion gas in the coolant.

Good luck.

Spent a bit of time working on the bongo and found weird thing happened to the glow plug relay wiring.
last time i drove it the battery went complete flat within 2 hours.
I was thinking the battery developed a short circuit inside the cells and i need a new one.
I have charged it and it was out of the car for a couple of weeks keeping the correct voltage - proving that it is ok.
Yesterday i connected it and after a couple of mins very bad burning/melting smell started coming from the front
Had a look and discovered that both fat wires connecting battery->relay-> glow plugs was touching each other and the insulation of the wires started melting and smoking. probably old failing/cracked wires and the high amp shorted them just before /2-5 cm/ from the relay.
having that circuit constantly on will cause the glow plugs to produce heat all the time does not matter if the engine is running or not.

here is my question do you think having glow plugs constantly on /producing heat/ can cause the engine to overheat.

After doing two sniff tests /BT-3 BLOCK COMBUSTION LEAK/ and pressure test with a bike pump to 1.1 bar did not show any leak.
Tested 4 glow plugs with a ohmmeter and two were gone - probably this explain the lumpy starts and the smoke for the first minute.

I have done bleeding yesterday evening, but have not got enough time to run the engine for more than an hour.
I am going to run it today for a longer time to check if the engine will overheat again.

also was cranking the engine with a white paper on top of the wholes where glow plug sits - have not got any water going out
PS: have drilled two holes on the thermostat - kind of bypassing it in case does not want to open every time. /Have tested it couple of times/different days in a boiling water and it opened every time

will keep you updated - hoping the gasket/head are ok.

The glow plugs should have a fusible link direct from the battery before it reaches the relay to prevent the wires being damaged by shorts, has this been removed/replaced perhaps ?