Bongo coolant fill and bleed video transcription

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BongoBongo123
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Bongo coolant fill and bleed video transcription

Post by BongoBongo123 » Mon Apr 11, 2016 2:21 pm

I know I would have liked a version I could print out and have as a reference, could not find one as per the excellent videos Haydn made for Youtube, the videos are great but I have only a mobile phone so jogging back and forth could be a tad tricky in the heat of the filling moment. So I transcribed this and got it checked with Haydn via PM. It covers salient mentioned points, of course it is Haydn's work but I thought others might benefit and this is what this place is all about !

Like any car job the more you prepare the better.

Refill and bleed of coolant for Bongo 2.5L Diesel - approximate transcription
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You will need a funnel for radiator and header tank, prepared 50/50 mix of coolant and water, leather gloves and probably waterproof ideally. Funnel that will fit tightly on the end of the bleed pipe. Some kind of header tank "dunker" so you can see header tank level on it as it is hard to see inside the tank due to discolouration and darkness within. And a bucket.

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Radiator cap under plastic cover
Bleed hose, check for chaffing/rubbing on engine
Remove bung on bleed pipe end
Big funnel slot into hose (pre-prepare this so it fits tight)
Waterproof and leather gloves (going to get hot fluid near or on your hands)
Bleed hose to be held higher than header tank
Take rad cap off
Fill with coolant 50/50 mix
Funnel in rad cap - small watering can
13 litres total capacity
Keep filling rad till it overflows
Eventually fluid gets to the bleed pipe funnel
Lower funnel slightly to see coolant level come in with air bubbles coming out
When rad full put cap back on


Start header tank filling
Lower bleed pipe funnel, will fill if lowered so keep it high !
Fill header tank to brim
Release rad cap till it overflows (ensures pipes to header tank are full of coolant)
Sea sawing - engine cold
Get coolant level up into bottom of funnel (pipe hole) and eventually above.
Sea Saw up and down not letting the funnel level drop (NO RUSH) go slow and easy avoid air/bubbles sucking inwards. Bubbles shout come out (slow)
As air comes out coolant level should "settle down"
Keep an eye on coolant level during sea saw
2nd person must check header tank NEVER EMPTIES and bleed funnel should never empty.
Put stick in header to check level (overflowing is fine losing level and empty is not fine)
As air comes out it is replaced by coolant and levels will drop so add more coolant to the header tank.


Next start engine for heat = The goal is to open the thermostat.

Engine running
Keep sea sawing (hopefully water pump pushes oput more bubbles)
Continue Sea sawing bleed funnel
Keep header tank full
Process can take 20-40 minutes
Engine is warming up slowly at this stage
Throttle up to 2,000-2,500 RPM
Level drops in bleed funnel with lowered funnel
Revs drop - cloudy fluid bubbles up
Check if front heaters are blowing warm
10 mins with throttle
Cloudier fluid in bleed funnel
Once it fills up when throttle applied level will drop in bleed funnel.
Still monitoring header tank !
Throttle person runs around to check (if only 2 people)
As funnel empties coolant is going back to the header tank.
Lift funnel during revs ! (goes back to the header tank)
25 mins in approx
Revs = lift funnel height
No revs = Funnel drops down (try and maintain continuous funnel level)
12 second revving periods noted
Bottom hose passenger side of radiator under front of Bongo
Should be COLD
As thermostat has not opened yet 65C- 75C
Awaiting thermostat to open
Bottom hose MUST go hot to touch
Takes time for this to happen keep on going !


Watch for more bubbling when thermostat starts to open.
Level does not go down in funnel (or as much)
Stat opens around 80C-85C
Should keep bubbling at bleed funnel
Throttle should not reduce funnel level at this stage.
Should see a nice burp when thermostat fully opens. (Hovers around thermostat opening temp for a good few minutes)
May get tiny bubbles from water pump cavitation
Now get to point to get header tank level right by emptying the bleed pipe funnel into bucket.
Get the bung ready so you know where it is to hand !
Bit of throttle
Check Header tank level
Put front heater on check if HOT if so turn off.
(Also can check rear heater)


No revs, pour last bit of coolant out of bleed funnel into bucket.
Watch level - keep eye on Header tank level
Level fluid to hose end hole and gently remove funnel - drop hose height and as it dribbles out bung it. Be careful as coolant is very hot.
Check no hose chaffing when putting it back in position.
Make sure level good in header tank
Put Header tank cap on.
Keep an eye on header tank level and temps for a few days till you are confident all is well.

As my additional safety tip it might be a good plan to be aware of the potential for very, very hot coolant to come out of the funnel in various potentially unexpected ways (on the fact sheet it has been mention it can spurt ! With this in mind even if unlikely a pair of goggles would clearly be the absolute safest way to proceed)
Last edited by BongoBongo123 on Mon Apr 11, 2016 2:28 pm, edited 2 times in total.
philpdr
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Posts: 717
Joined: Thu May 20, 2010 7:58 pm
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Re: Bongo coolant fill and bleed video transcription

Post by philpdr » Tue Apr 12, 2016 1:40 pm

Good idea,will come in handy for sure. =D>
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