Bongo Fury

Hi I bought a 2002 v6 Auto 2.5 here in Toulouse Last week, seems good condition although only done 3000km in last 2 years and I don't think well maintained. Coolant was well below min (now topped up)but oil good and clean. Ran Bongo to work (20-25min) 4 days no prob. Temp gauge performed as it should according to what I've read in forums, 10mins and goes to 11 o.clock position. Coolant level remained good. Decided to test properly at wknd and took Bongo to Andorra! didn't quite make it as blizzards closed roads fitted snow chains and Bongo performed great on slippy hairpins in Pyrenees. Only concern the temp gauge dropped to Zero after about 50km on motorway this coincided with the heaters cooling off a bit. We had them on 26 degrees as it was minus 12. Once we hit the mountains with snow chains on the temp gauge returned to normal as we were climbing and descending slopes with chains on at 20-30km/hr for a few hrs.. no problem there.. After a few detours to try and get thru conditions were too bad and headed back to Toulouse. Again on the motorway while sitting at 90-100km/hr the gauge swung to Zero and again the heater cooled a little. We stopped for fuel and to check coolant levels etc and all seemed as it should be. The gauge was ok for the last leg home. Everything seems ok, hoses etc look good condition. I'm no mechanic but from reading other parts of the forum was thinking thermostat change?? My main concern is the engine is not being managed properly by the cooling system if wrong signals are being sent.. or would it just be the gauge? the fact the heaters cooled off at the same time concerned me. Any clues and advice greatly appreciated. ta.

Hi, welcome aboard.

If the coolant hss dropped below the header tank the V6 and diesel Bongos need the system bleeding.

There are 3 You Tube videos showing how to do this, and have a search on here.

Low coolant often results in a cracked head on the diesel but the V6 seems less prone to this.

My advice is don't drive it until the problem is sorted.

Good luck.

at disel bongo I drove at 2000 km when the head cracked...
1.remove the thermostat
2. put more water
3. not sad

Cheers Bob, is my intention is to bleed the system once I get the bongo back to UK in Feb, but at the moment just keeping an eye on things. it's been sweet the last 3 days driving to and from work. I think the only reason the expansion tank had dropped below min because it wasn't topped up in 2 yrs or even looked at by the previous owners admission. It only did 3000km in that time so probably evaporation rather than a catastrophic loss? .. Like I said it was the swing to Zero after half an hour on the motorway that concerned me. So really need to take on another long run to see if it's recurring.

Could it be an airlock causing the OP's symptoms? Especially if it's a V6 which has not been properly bled following a low coolant situation?
I've only once had a temperature gauge drop to zero, on another slightly delicate engine, a Rover K16. This was immediately followed by it going to maximum deflection the other way, beyond hot. Yes, I had HGF and the entire system was empty. If the Bongo recovers and reads normally - and the header tank level appears to be correct - it would seem to point instead towards an airlock.