Hello everybody,



I just got back from vacation...put my radiator back in after it was cored out...put on new plug wires...even got my new stereo in...



And my car is still trying to overheat...I did notice some smoke coming out of the pump thing on the passenger side of the engine...the one that kinda down and in front of the carb/air intake stuff...its been doing it since she started overheating but I thought it was just fluids burning off



I don't see anything leaking out anywhere..just white smoke from that general area after shut off



Just like it used to do my engine will climb up to where it will almost stuff off...then it usually will slowly drop back to where its just a little bit from the second orange line on the left of the heat guage



I have also noticed my choke doesn't kick off when the engine is warm anymore...we recently replaced the thermostat...it could possibly be part of this problem but I doubt it...



Also had the "coolant" light and buzzer on after I started my car up...seemed to shut off till the heat guage climbed up...probably opened up the thermostat and let the rest of my coolant in...I dunno



Someone give me some ideas of what to do...please...I'm lost



Adam

 

Hi Falcoln, wooffinn from downunder. Man you've got a list of problems there!! Firstly, not quite sure what you mean about that pump. Is it possibly the air injection pump? I've got to remember that my steering wheel is on the opposite side of the car in my country!! I know I've removed a few of them for customers because they basically sieze up. May be your smoke, don't know.

The choke prob may be the internal bimetalic spring has come off or broken. Again I get quite a few in the workshop now but there may be a difference between our models. Not an easy problem to fix yourself without a spare carb to steal bits off.

As a mechanic who has been fixing cars for too long, I've learnt to never trust a thermostat, even new. A easy check is to grab your kettle and a container and wire to suspend the thermostat in the hot water. Technically you should have a thermometer to check water temp. ,but as long as it opens fairly quickly in the boiled water, you can assume its ok.

Another part that usually overlooked as the old radiator cap. This little bastard can, in unlucky circimstances, cause all of your problems. Believe me, I've pulled the hair out a few times before discovering a new cap was all that was nedded!!

The water sensors are ususally fairly reliable,so just check your water level cold before going on further.

Another quick point I've found fixing Mazdas. Don't always trust your dash guage/sender. If a had a dollar for every Mazda temp guage sender unit I've replaced, I'd be a rich man!!

Unfortuneately, it could also be an internal water jacket/o ring problem, but I hope not!! Hope some of this helps.

 

Could you tell me more about this air injection pump?

The pump I have on the right side of my car has a hose coming from the the air intake that goes into the top of it...



We saw some bubbles coming out around the back seal of the thing...my dad said it almost smelled like burning anti-freeze



He just found it in my fix it book...it is the air pump

would this explain my overheating problem?

I have also been getting worse mileage recently...16 instead of 20

 

Hi Falcoln,wooffinn again.I imagine these pumps are a fairly universal style, but down here it's a emission control device. As we know, the old rotary isn't the cleanest engine in the world, so Mazda added these units to lots of their vehicles, both rotary and piston. Basically it's adding/recycling some intake air and adding it into the spent exhaust gases and hopefully reducing HCs(fuel( and Nox(greenhouse( gases.

The two main reasons I replace/remove them is they drain HP from the engine and they,with age, seize. Mazda say they're a servicable item, but I can't bits for them! They do have a certain amount of fine oil inside to lubricate the internal bearings, so that may be your fluid that you can see. Our emission rules down here aren't inforced very much, so basically these pumps are a 'over the shoulder item!'. If you need to have one to comply, I'd suggest sourcing a second hand one, as new new ones here are ridiculously priced. I assume it is belt driven, so to check it, just remove the belt and spin the pulley. Just look and listen for any roughness/play. With that air pipe off, it should,as you spin it, pump air out and make a kinda 'pop' noise. Unfortunately though, I haven't had one of these units cause an overheating problem, so you may need to keep looking.

 

If I just removed the belt would that be enough to disable it?

Would removing it not affect my mileage in some way?



My cats have been removed...replaced with a straight piece of pipe...as we have no emissions checks...so I don't have to worry about being legal



As for my overheating problem I have noticed something...if I start my car and only let it warm up to the second yellow line on the left...then let the choke off and go...it runs fine



If I let it idle for a while and it reaches the middle of the guage it usually reaches the danger zone before I get a mile down the road...if I stop...turn off the car...and then turn it back on...the guage seems to drop back to normal ranges...closer to the 2 lines on the left side



I'm starting to think I have a sensor going out...where would I find the sensor for the heat guage...or sensors?

 

Hi Falcoln, wooffinn back again. Yeah for sure, removing the belt would stop that pump, but I'd recommend removing the unit. It will just be dead weight hanging in the engine bay.Any hoses to the air box, just seal up to stop dust entering. I think you might be in the right area with your heat problem. All the senders I've seen play up tend to do what yours does, ok for a bit, go stupid then seem to fix themselves. As for the location, in my neck of the woods , the sender unit for the dash guage is in the top tank of the radiator, next to the top radiator hose. Whether it's the same in the US I'm not sure, so maybe if any of my fellow US rotor people are reading ,you may be able to enlighten us both.