Can anyone help diagnose Mazda problems?

[!Gn|T|0n]

Good morning all.

I know it's a ford forum but you people are quite switched on and the mazda forums seem slow so here are some symptoms for you.

My girlfriend owns a 1989 323 astina SP DOHC and it has become a little sick recently. For some weeks now the car has hunted quite badly.. from (very roughly) 500RPM to 1200/1500 ish RPM and would on occasion stall.

There was nothing else wrong with the car at that stage so I suggested fuel injector cleaner which we've yet to run through the motor. Just yesterday the car overheated after a stint on the motorway. The reservoir was almost empty; the water that was in there was boiling. I pulled over and let the car cool down. I filled the cooling system up again (it took a couple of litres!) and noticed that my girlfriend had recently replaced the radiator cap. It is rated at 13lbs (I don't know much about mazdas but does this sound a little low?) I thought that if the cap was opening prematurely then the cooling system would not be operating at correct pressure, both lowering the boiling point and loosing coolant through the reservoir. This morning I thought I'd give her a chance to prove my hypothesis. I started the car (stone cold) with the radiator cap off and immediately the coolant started to "froth" and "bubble" (combustion chamber pressure forced through the coolant system?) The idle was notably rough and during a short drive I noticed that the car had no power (lost compression??) and blew clouds of whitish smoke. Although it did have a distinct smell, the smoke didn't smell like oil - perhaps steam mixed with exhaust gasses? What do you suggest? Does it sound like a head gasket? The oil is not milky but that would depend on where the gasket has gone, no?

Thanks for your comments.

[Racecraft]

yea mate unfortunately :(

The white smoke can be a combination of coolant and water. Sounds like the gasket has gone on the exhaust side. Did it smell kinda 'sweet'?

[Yaw]

Originally Posted by !Gn|T|0n

Good morning all.

I know it's a ford forum but you people are quite switched on and the mazda forums seem slow so here are some symptoms for you.

My girlfriend owns a 1989 323 astina SP DOHC and it has become a little sick recently. For some weeks now the car has hunted quite badly.. from (very roughly) 500RPM to 1200/1500 ish RPM and would on occasion stall.

There was nothing else wrong with the car at that stage so I suggested fuel injector cleaner which we've yet to run through the motor. Just yesterday the car overheated after a stint on the motorway. The reservoir was almost empty; the water that was in there was boiling. I pulled over and let the car cool down. I filled the cooling system up again (it took a couple of litres!) and noticed that my girlfriend had recently replaced the radiator cap. It is rated at 13lbs (I don't know much about mazdas but does this sound a little low?) I thought that if the cap was opening prematurely then the cooling system would not be operating at correct pressure, both lowering the boiling point and loosing coolant through the reservoir. This morning I thought I'd give her a chance to prove my hypothesis. I started the car (stone cold) with the radiator cap off and immediately the coolant started to "froth" and "bubble" (combustion chamber pressure forced through the coolant system?) The idle was notably rough and during a short drive I noticed that the car had no power (lost compression??) and blew clouds of whitish smoke. Although it did have a distinct smell, the smoke didn't smell like oil - perhaps steam mixed with exhaust gasses? What do you suggest? Does it sound like a head gasket? The oil is not milky but that would depend on where the gasket has gone, no?

Thanks for your comments.

13 psi for a cap is about right.
Since the car had little coolant in it may suggest a blown head gasket and yes it does depend where it is blown. It may also represent a cracked head.
Don't stress most times that is repairable. Best and easiest way to test this is by going to a mechanic to do 1. a pressure test on the radiator. 2. a compression test on the motor. However after the repair is done (if this is the case) I would aslo suggest you need a new temprature sensor otherwise you would have noticed that earlier before damage occurred.

Possibly that may be a secondary problem though. it could also be like a timing issue also causing the motor to run hotter by using a lean mixture which then caused the rest. Not sure if mazdas run belts of chains.

[EA2BA]

A mechanic should have a simple test to pressure test, or check for exhauts gasses in the water/coolant, but I am willing to bet headgasket as gone right near an exhaust valve (if the car has good rings and the leak is not too big then water doesnt get in the oil).

[!Gn|T|0n]

Yeah tibbo it's a hard smell to describe... sweet may be a word I'd use. I usually scan the gauges whilst driving so I'd be surprised if I didn't notice the temperature rising earlier in the day. Could it have been eating coolant slowly such that I wouldn’t notice a gradual temperature increase but rather a fairly rapid one once the level became critical? I'm a little surprised that it seems to have happened over such a short period of time. Is this typical of head gasket failures?

I haven't yet done compression / pressure test but will do so.

Thanks again.

[Racecraft]

V-man it depends on where the sender is on the Mazzie, some of them (i think maybe the early E series were like this too) are in the block or located on the housing not actually reading water temperature until there is none. When any alloy head get hots the gasket will be the first to suffer so in answer to the period of time being short, yes it is more than likely

[EA2BA]

my E-series (1988 series 1)is in the thermostat housing. XF I think were the last to be in the block.