Mazda929.org

hi there,

i'm a bit of a 929 newb, i inherited my pop's 1989 929 V6 after he passed away last year, and this year i decided to get it going again and use it as my daily driver.

anyhoo, to cut a long story short, I have got it reregistered, but am having a little trouble with the cooling/heating systems.

every time i fill the radiator, most of it seems to end up back inside the car, as it leaks on the passenger side all over the nice carpet. it only does this once it starts to warm up a bit. if i turn the heater on, i actually get steam coming out of the vents, which does draw some funny looks at the traffic lights (hey, mobile sauna!!).

The thermostat has been replaced, and i have tried flushing the system several times to see if there is any blockages.

I would like to be able to use the car on longer trips, not just the very short commute to work each day. I haven't got water in the oil, it hasn't gone milky so I think the head gasket is ok.

The other problem is that the top radiator hose outlet has snapped off, so i only have a little bit to put the hose on, and it keeps popping off. Should that really feel like plastic? How is that fixed?

Thanks for any help!

Welcome

ok, the heater core is easy to block if you look at your firewall you will see two identical hoses closely spaced going into firewall (i think they are 10mm hoses) which are angled down, just disconnect them. they will connect to a 90 degree "nipples" from heater core. just be gentle as plastic would have aged and will easily cracks and snaps. Get a hose joiner and just join the two hoses, vola, no more heater

or just get a replacement unit, even from a wreckers, they are not that complicated to replace, fiddly but not complicated

radiator has plastic tanks, so yes it can snap, you can glue it using some hardcore glue or plastic weld (not sure on this one). maybe you will be able to replace it with a barb for hose fitting, speak to radiator specialist they might be able to replace the tank... sometimes that works out to be cheaper then any band-aid solution

OK cool, I did try removing the hoses, but geez there isn't much room down there, I could barely get the pliers in for those horrible clamps. I might end up just cut them to join them up (but i will make sure i can get replacements first!).

I'm only fairly basic level mechanicals and tools so I baulk a bit at having to remove other stuff to get to things. I will get the heater core replaced at a future stage, this is just more a stop-gap measure to stop it leaking in the cabin.

Another question if I may, is it normal for the car to produce a lot of steam? At the moment, as soon as the car warms up, it starts shooting steam out of the top hose (as the connection isn't great). Before that it was going into the overflow tank making it bubble away. The temperature gauge is still rising a fair way (still in the shaded zone, but getting high). I dunno if there is still a blockage somewhere in the system, the bottom hose does feel hot after it heats up, so the water does seem to be cycling through, but why get so hot?

steam in the system is not a good thing, the system should be pressured and if you get steam out then you loosing pressure. i think you should head to a wreckers and get another solid radiator.

this car relies heavily on two things:
* vacuum
* Coolant

the coolant controls idle, fuel usage, cooling (duh )

so first, get radiator replaced and get pressure back in there. second, replace top and bottom hoses (also check the thermostat while you at the bottom). then rise the front of the car, tape a 2L bottle to the filler (with the bottom cut out), fill the system to the point that you have coolant mix about 1/2 way in 2L bottle.... let it run till it runs to appropriate temperature. these cars do not have coolant bleeding system, so you have to 'burp' it that way.

air in the coolant system would make your coolant sensors go wild, your temp may rise (even through it is not overheating) or could go another way too. you idle will jump around every time bubbles pass your idle valve.

Okey dokey, a lot of what your saying is making sense.

So, if the system was properly pressurised, the steam wouldn't be there? I will look into a new rad for sure. Definately have to look at doing that burping thing too, my cold idle is like over 2000rpm! And after a short run, the idle goes crazy like I'm pumping the accelerator. When it warms, the idle does die down to a more "normal" level. Lots to think about!! LOL

I know this is a little old but was wondering if there was a fix to the heating system. Im haveing the same problems with the cold idle at 2k and auto rev to about 3k and the bottem hose staying cold while the top one is very hot and when you turn the car off you hear a bunch of bubbling sounds. Iv replaced the water pump 2 years ago and im not getying any leaks and also just put ina new thermostat along with new coolent.

If your bottom hose is cold means the coolant is not entering the engine, have you checked your thermostat? (also make sure you use dual stage, it matters on these cars), check your radiator and pump, clearly you are not getting flow.

Pump could fail and not leak.... also seen cheaper pumps wear out and simply did not provide any flow.