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Temp alarm following coolant change
Posted: Tue Feb 18, 2020 6:17 pm
by cobbdu1
We had our MOT last week, and we asked the garage to change to coolant completely, following advice from this group. They replaced the green coolant that was there since we bought our Bongo (an import) and put in red coolant instead. On our first outing the temperature sensor I installed last year reached 100C and the alarm went off. This has never happened before. The coolant levels are high so it doesn’t appear to be leaking. Can anyone offer any advice please?
Re: Temp alarm following coolant change
Posted: Tue Feb 18, 2020 6:36 pm
by Bob
Which engine do you have?
And did you use a Bongo Savvy garage, ie, was it bled properly?
Re: Temp alarm following coolant change
Posted: Tue Feb 18, 2020 6:44 pm
by cobbdu1
2.5D
I believe they are Bongo savvy. They’ve dealt with a lot of Bongos as they were recommended by someone on a forum and got loads of business as a result. Though they’re not Bongo specialists. They’ve just seen a lot of them.
Re: Temp alarm following coolant change
Posted: Tue Feb 18, 2020 6:45 pm
by cobbdu1
I’ve contacted them and am dropping it off tomorrow. Hoping it’s something like an air lock that is easily remedied.
Re: Temp alarm following coolant change
Posted: Tue Feb 18, 2020 6:58 pm
by Bob
Fingers crossed. [-o<
Garages recommended by the crew here are generaly pretty good, can't fault them taking a look.
Re: Temp alarm following coolant change
Posted: Wed Feb 19, 2020 6:11 pm
by haydn callow
Different coolants have different cooling abilities....
100c isn’t silly high depending on what you were doing.
What temps were you recording before, under the same conditions.
Re: Temp alarm following coolant change
Posted: Wed Feb 19, 2020 7:45 pm
by cobbdu1
The alarm has got to 100C once before, after a long uphill, and it quickly cooled down once we got on the flat with the faster air cooled things down a bit. Yesterday’s driving was normal.
Meanwhile, I took the Bongo to the garage this morning. The alarm was sounding even though the temperature was below 10° so I figured the alarm needed resetting. In the garage they said the coolant level had dropped significantly and so they suggested that the airlock might have removed itself overnight. When I checked the coolant yesterday, whilst the temp alarm was going off, it was well above the fill line. Given what the garage said it would suggest that the coolant level did indeed drop and the alarm I heard this morning was actually the coolant alarm instead (it sounds the same as the temp alarm). So hopefully the problem has corrected itself. The garage said that they think it will be alright but to take it back to them if we have any issues.
Re: Temp alarm following coolant change
Posted: Wed Feb 19, 2020 8:06 pm
by Bob
Sadly, I've never heard of an air lock (in a Bongo) 'removing itself'.

Re: Temp alarm following coolant change
Posted: Wed Feb 19, 2020 9:39 pm
by haydn callow
After a bleed the coolant level often drops .
Re: Temp alarm following coolant change
Posted: Wed Feb 19, 2020 10:12 pm
by Bob
True Haydn.
What would be a normalish amount, would you recon?
Valuable info for us all.

Re: Temp alarm following coolant change
Posted: Wed Feb 19, 2020 10:52 pm
by haydn callow
Half litre or a pint’ish
Re: Temp alarm following coolant change
Posted: Wed Feb 19, 2020 11:22 pm
by Bob
Thanks, that is useful.

Re: Temp alarm following coolant change
Posted: Thu Feb 20, 2020 9:26 am
by haydn callow
I think the amount depends on how successful the bleeding has been, I bled loads of bongos and had to top up very little, but many peeps stop very soon after the stat opens. This can leave air in odd corners which is expelled after a day or so and drops the coolant level in the tank.
Re: Temp alarm following coolant change
Posted: Thu Feb 20, 2020 10:55 am
by JulesMartin
previously before i did my head when I was bleeding I'd stop pretty much after the thermostat opened and always had to top up the next few days but I put that down to the head being suspect, which to be fair, it was. Since doing the head on the two occasions where I've had to bleed it out again (metal heater hose replacement and heater hose) I bleed out until the fans cycle a couple of times. probably takes an hour in all but I've found much more success with the level staying constant in the header tank. I'm thinking that in this case the garage is on a time restraint to get the job done and hoped that it would settle itself down after a couple of days. Bongo's don't play like that do they!