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heaters blowing cold overheat problem

Posted: Thu May 13, 2010 12:17 am
by wrighty
tonight on a short 5 mile journey on a very cold night i switched heater on and it was blowing cold i stopped lifted bonnet and noticed all my coolant was exitting my car via the reserve bottle overflow pipe. it was bled a few days ago and has seemed ok(after noticing and repairing a leak from a hose that ran from top of rad to a metalpipe further down that looks like it runs to back of car)
what is likely to be my problem here so i have somewhere to start from when i begin to work on it. my first thought is the thermo stat would i be right on that and is it a long job finding it and changing it. help please
just to say that it blew out of the overflow pipe until bottle was empty and it was making an awful gargling sound for around ten mins after :cry: :cry:

Re: heaters blowing cold overheat problem

Posted: Thu May 13, 2010 12:22 am
by Northern Bongolow
KIRSTY!!!!!

Re: heaters blowing cold overheat problem

Posted: Thu May 13, 2010 12:26 am
by Northern Bongolow
seriously.
did you bleed it properly after the previous leak, was the system pressure tested,any previous issues??how long did it run hot,were the fans on.

Re: heaters blowing cold overheat problem

Posted: Thu May 13, 2010 12:55 am
by missfixit70
Sounds to me like it wasn't bled properly & there was an airlock, won't hurt to put a new (genuine mazda) stat in, it's under the passy seat - part 15-171 on here - http://www.lushprojects.com/bongopartsm ... mgno=.html

Re: heaters blowing cold overheat problem

Posted: Thu May 13, 2010 9:18 am
by wrighty
this is going to sound daft but i live on a very steep hill and bleed it on said hill do i need to be on the flat to do it properly. also how much water(coolant)does the system hold. thanks

Re: heaters blowing cold overheat problem

Posted: Thu May 13, 2010 11:38 am
by haydn callow
!3 lts in total....I bleed them on the Flat but pointing uphill might help....Pointing dowhill is a No No.
When bleeding....follow the instructions exactly.....GET THAT BOTTOM HOSE HOT !! allow 30/40 mins.

Re: heaters blowing cold overheat problem

Posted: Thu May 13, 2010 1:03 pm
by wrighty
ive done it on flat uphill and downhill today(on flat last) over a 2 hr period using both methods bucket on drivers seat and funnel way. bottom hose hot and now going to see if its done the job. also blowers blowing hot
need a few pointers how and with what do you do a pressure test with. and an address for the nearest garage or person that is experienced with bongos(maybe somebody local to me that enjoys working on them and can use the pocket money )thanks again people for your help.also got a bit of time today so going to look through forum for other threads relating to same so ime not repeating things

Re: heaters blowing cold overheat problem

Posted: Thu May 13, 2010 1:26 pm
by missfixit70

Re: heaters blowing cold overheat problem

Posted: Thu May 13, 2010 1:45 pm
by wrighty
on reading that thread. when it was on about using the pump and air into the expansion tank pipe youde hear hissing from the rad cap if you overdid it, i remember that when i put the cap back on and bleed pipe blocker back on i squashed the lower hose and noticed a burp from the over flow pipe every time i squashed it would this be normal(it was just after i finished bleeding and everything was still very hot)or is the rad cap faulty and thats where ime losing coolant from. going to get garage i normally use to do a pressure test and cylinder head gasket test i think (when i get some coin out of work at minute)

Re: heaters blowing cold overheat problem

Posted: Thu May 13, 2010 3:41 pm
by missfixit70
Not normal to get anything coming out of the overflow/vent pipe, I take it you mean the rubber pipe that comes from the header tank cap (that should be a 1.1bar)? if the pressure cap is tight but air is coming out of the vent when you squeeze a hose, it sounds like the pressure cap is not sealing on the bottom seal, try swapping it with the rad one if that's got a 1.1 bar cap, or get a new one, make sure the lower sealing face on the expansion tank is not damaged as well.
The rad vent should be blocked off & it doesn't matter what cap is on there as long as the top seals, the rad cap shouldn't vent at all.