Radiator Fans

connico · Postby **connico** » Mon Nov 10, 2008 3:39 pm

Hi guys,

Long story short, I need to know how to check the secondary radiator fan. I suspect its not working as it gets pretty hot in the engine bay and it looks that its one of the sources of my problems with the car spluttering to a stop till i cools to get it going again.

Regardless, is it possible to wire it so it runs all the time?

Sorry forgot to mention it was an

NB 01

bensale · Postby **bensale** » Mon Nov 10, 2008 3:49 pm

It would probebly help if you define which model you have. On an NA6 you can do it. You bridge the GND and .... termainals, cant quite remember which ones.

GP · Postby GP » Mon Nov 10, 2008 4:07 pm

On mine 1 fan works only when the AC is turned on

Postby **Okibi** » Mon Nov 10, 2008 4:27 pm

On the NB only 1 fan works (once the car temperature gets to about 210"F/99"C I think) the other only works when the A/C is engaged.

You can modify it so both come on once it hits temperature to cool the radiator down faster.

connico · Postby **connico** » Mon Nov 10, 2008 4:49 pm

Basically the temperature is messing with the car electronics. I noticed that car is running pretty hot, hotter then any other car I have. I have checked almost everything and it seems like the Second Fan is not kicking in at all.

Postby **Okibi** » Mon Nov 10, 2008 5:28 pm

Ok, riddle me this ..

Get the car up to temperature, should take at least 10 mins normal driving.

Park and keep the engine running, carefully pop the bonnet and see if any fans are running, if it's really up to temp you should have ONE fan running.

THEN ..

Lean inside the cabin and turn your aircon on, BOTH fans should be running. If this is the case then your fans are working as they should be.

Let us know what happened. It could be that your radiator is blocked and the fan isn't able to cool as much as it should.

Mr Morlock · Postby **Mr Morlock** » Mon Nov 10, 2008 5:38 pm

Far from an expert on cooling but it is not logical that you need to wire a fan to work all the time if they were not designed to do so. I would be first suspecting a cooling problem such as a radiator in need of cleaning. At this time of the year I am guessing that the system is not under stress so a blast of good old Aussie summer may very well make your problem worse. You might save time in fault diagnosis by getting the system checked by a pro.

wun911 · Postby **wun911** » Mon Nov 10, 2008 6:03 pm

Its only for the AC it can be removed for weight reduction :idea:

If its hot where you live you can re wire it, so BOTH fans turn ALL the time.
http://www.miata.net/garage/parallel_fan.html

Does running both fans take power from the engin like as if the AC was on???

Does anyone run without a thermostat ie the thermostat is missing/drilled/angle grinder, less weight and is now considered ALWAYS fully open? (Just for summer and track will put it back later in winter)
Out of curiosity does anyone run a large aftermaket rad then remove both fans to save weight? What is the capacity L please?

When was the last time you changed coolant?
When was the last time you changed the thermostat?

connico · Postby **connico** » Mon Nov 10, 2008 6:13 pm

Mr Morlock wrote:You might save time in fault diagnosis by getting the system checked by a pro.

It has been to Mazda Australia in North Ryde, they had the car for 3 days and could not find a fault. I actually drove it for like a 3 weeks before it spluttered to a halt on Parramatta road. It was a really hot day and I had my air con on. Let it rest for 30 minutes and I was off again.

I have also noticed that while driving and the engine in is on normal operating temp its gets hot around my feet.

Regardless Ill do this Air-Con test

Postby **Okibi** » Mon Nov 10, 2008 8:07 pm

Don't trust the NB temp gauge too much, its more of an on/off switch. it tells you the car is within acceptable temperatures OR if it's too hot.

My NB gauge says it's up to temp about 4-5 minutes before the thermostat opens, and it says in the same position no mater if the coolant is at 180"F or 210"F.

If you're still unsure, take it to the Mania dyno, make sure they take the time to put temp probes on it, and watch the fuel mixes carefully. You might get a better understanding of what's going on.

Sounds a bit like coils overheating.

connico · Postby **connico** » Mon Nov 10, 2008 9:31 pm

Okibi wrote:If you're still unsure, take it to the Mania dyno, make sure they take the time to put temp probes on it, and watch the fuel mixes carefully. You might get a better understanding of what's going on.

Sounds a bit like coils overheating.

Personally i thought it was the coils or the CAS... But Mazda have said they tested both. I am unsure what kind of testing they did but regardless I would not mind putting it on the Mania dyno. does it require a booking?

Dave · Postby **Dave** » Tue Nov 11, 2008 6:38 am

connico wrote:Hi guys,

Long story short, I need to know how to check the secondary radiator fan. I suspect its not working as it gets pretty hot in the engine bay and it looks that its one of the sources of my problems with the car spluttering to a stop till i cools to get it going again.

Regardless, is it possible to wire it so it runs all the time?

Sorry forgot to mention it was an

NB 01

connico - I have had the SP warm up a few times in traffic (hot days only) lately, and found that wriggling the plug (had to unclip the wiring harness to the AC fan just above the plug) brought it back to life, and kept the temp normal in traffic again. No visible arcing or anything on the plug itself - however something must be sensitive in there...

Rgds, Dave

Garry · Postby **Garry** » Tue Nov 11, 2008 8:23 am

What drifter said.

If the engine stops running when it's hot it's nothing to do with the cooling system (unless you boil it and seize the engine). The cam position sensor can fail and not produce an error in the ECU. It usually fails when it gets hot then starts working again when everything cools down. I'd be looking there for your answer.

Does anyone know if the auxilary fan comes on as well when it all gets to much for the main fan? It does on the SP and I was wondering if this was an SP mod or if thats how Mazda designed the system?

GP · Postby GP » Tue Nov 11, 2008 10:47 am

Does running both fans take power from the engin like as if the AC was on???

Yes, But probably not to the same degree.

Does anyone run without a thermostat ie the thermostat is missing/drilled/angle grinder, less weight and is now considered ALWAYS fully open?

If you run without a thermostat the engine will overheat.

sabretooth · Postby **sabretooth** » Wed Nov 12, 2008 11:12 pm

Running without a thermostat only means that your engine will take forever to warm up, and a an engine not fully warmed-up engine is not good for longevity.