steam from under hood

Technical questions and answers about the Mazda Bongo

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bongomadness

steam from under hood

Post by bongomadness » Sun Sep 12, 2010 10:54 am

van has been running great since having the new pipes fitted and it went to wales no probs and no issues but yesterday went out on a small jaunt to local asda and when i arrived there was steam coming out from under the bonnet............no raise in temp showing on guage and its also had a new stat fitted.There was some water splash marks under the hood as though something has squirted. no pipes seem to be leaking and xpans bottle is at correct level,radiator doesnt appear to be leaking..............................any ideas anyone??????? Could it be a air lock in system ????? As usual any help greatly appreciated
P.s On top of radiator there is a little metal pipe just under cap...should that be connnected to a pipe somewhere .checked on the l/p diagram but it doesnt show the pipe
Cheers

Jayne
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helen&tony
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Re: steam from under hood

Post by helen&tony » Sun Sep 12, 2010 11:23 am

Hi
Where are the "splash marks"...and although the water level hasn't dropped , you may have an air pocket somewhere...get someone local who knows how to bleed/ care for the Bongo cooling system to come and look at it....and don't drive it, and you may avoid damage
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Helen
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Re: steam from under hood

Post by nfn » Sun Sep 12, 2010 11:26 am

Is the radiator new? I believe that little pipe under the cap needs blocking off -- it can be done with a short length of coolant hose with a bolt shoved up it, and a hose clamp fitted to keep the bolt in place (i.e., similar to the the bleed hose setup on a Bongo).
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Re: steam from under hood

Post by waycar8 » Sun Sep 12, 2010 11:37 am

Basiclly its not a genuine bongo rad, I got one of these off ebay for my old bongo, and it kept weeping coolant out of the pipe in the neck of the rad untill I did what nfn descibed above.

Also check and make sure the rad cap is a 1.1 bar, as the one that came with the one I bought was only 0.9 bar, and the bongo system presurises more than 0.9 bar so it will lift the rad cap once up to pressure, If my theory is correct this is where the steam will be coming from, ie the coolant drying off on the rad as the rad cap lifts and seeps coolant out, make sure you swap it with your old rad cap or buy a new one asap if its only 0.9 bar that is.

Good luck and keep us posted
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Re: steam from under hood

Post by Northern Bongolow » Sun Sep 12, 2010 1:15 pm

agree with wayne and nfn,check the rad top pipe,and blank it off.
if its chucking out a bit of water and the level is not dropping in the expansion tank,this means it must have air in the cooling system,this must be bled out ASAP.
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Re: steam from under hood

Post by Doone » Sun Sep 12, 2010 2:54 pm

P.s On top of radiator there is a little metal pipe just under cap...should that be connnected to a pipe somewhere?
If that pipe is open, you will loose coolant. As has been said, it should be blanked off and you may need to bleed the system, better safe than sorry. I expect your garage will sort this for free, as it's their error. :)
Allans Garage retired. Try PGS (Plymouth Garage Services) or Mayflower Auto Services Plymouth
bongomadness

Re: steam from under hood

Post by bongomadness » Sun Sep 12, 2010 3:30 pm

Hi guys and thanks for the info. I did think an air lock but because its been over a monthe since we had the coolant issues sorted and because of the mileage we have done in that time i didnt think i could get an air lock plus I did think that maybe that pipe should be blanked off. The cap has nothing written on it so to be safe i am gonna get a 1.1 bar and get me mechanic out to bleed the system again. Better to be safe than sorry.
Thanks for your invaluable help again.......always appreciated.
Jayne
nfn

Re: steam from under hood

Post by nfn » Sun Sep 12, 2010 6:57 pm

A plain cap is fine, unless someone removed the pressure rating sticker from it, which seems unlikely.
bongomadness

Re: steam from under hood

Post by bongomadness » Mon Sep 13, 2010 7:58 am

I had a look under bonnet of my neighbours bonnet yesterday and he has the original bongo set up so no spiggot under cap but one thing does bother me ..............if mine is aftermarket and it is a pressurised system how come it did over a thousand miles after the system had been bled etc and now its squirting water?????Maybe there was a pipe there and it has fallen off or maybe there never was one but it just made me wonder.
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Re: steam from under hood

Post by Doone » Mon Sep 13, 2010 12:24 pm

I had a look under bonnet of my neighbours bonnet yesterday and he has the original bongo set up so no spiggot under cap but one thing does bother me ..............if mine is aftermarket and it is a pressurised system how come it did over a thousand miles after the system had been bled etc and now its squirting water?????Maybe there was a pipe there and it has fallen off or maybe there never was one but it just made me wonder.
Reading the forum, a few members have mentioned this problem and have driven a fair way before losing coolant. :)

There may have been a blank fitted and it may have fallen off, that is possible, but they should be fitted tightly so this doesn't happen.

Dandywarhol has posted details about the expansion tank cap and radiator cap ON THIS LINK.
Allans Garage retired. Try PGS (Plymouth Garage Services) or Mayflower Auto Services Plymouth
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Re: steam from under hood

Post by waycar8 » Mon Sep 13, 2010 5:00 pm

bongomadness wrote:I had a look under bonnet of my neighbours bonnet yesterday and he has the original bongo set up so no spiggot under cap but one thing does bother me ..............if mine is aftermarket and it is a pressurised system how come it did over a thousand miles after the system had been bled etc and now its squirting water?????Maybe there was a pipe there and it has fallen off or maybe there never was one but it just made me wonder.

Same happened to me, the logic thing I could come up with was, as I was driving the cap was lifting due to being the wrong presure rating, letting out a bit of coolant each drive, and taking in air as it was cooling down and shutting off, thus each time I drove it built up little bits of air, then in your case there was alot of air and as it got hot it expanded and forced coolant out due to presure??, fortunatley for me, I had my rad fitted a week before a meet, and when I got there someone wanted to take a look at it, thats when I noticed that coolant was leeking out of the pipe in the neck so I never got to the stage you did, as I blanked it off there and then with a bit of pipe and a small extension bar from a socket set from other members who were at the meet, then bled it.
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Re: steam from under hood

Post by scanner » Mon Sep 13, 2010 7:03 pm

no raise in temp showing on guage
And if you haven't modified the gauge in any way (mason alarm or similar) IT WON'T!

....and if you wait for a rise in temp to show, you will see it too late to do anything about it.
bongomadness

Re: steam from under hood

Post by bongomadness » Tue Sep 14, 2010 7:52 am

Thanks again guys.....mechanic coming over to blank off and re bleed at weekend. :D :D
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