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Discussion Starter · #1 ·
I searched, but found no reference - what is the suggested temp for the thermostat? 180 or 192?
 

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Neither, you want the Mazda OEM dual-stage thermostat, not the el-cheapo part from the local parts store. There is a sticker on your radiator support telling you this.

I dug this up from an old post of mine:

the mazda OEM thermostat has two valves on it, a larger one and a small one, so it opens more gradually. The first valve, called the "Sub valve" starts to open at about 85 C (185 F) (, and the second valve, called the "main valve" starts to open at about 88 C (190 F). It says that at 100C (212 F), both valves are fully opened. It also says to make sure the "jiggle pin" is at the top when installing the thermostat.
 

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Discussion Starter · #3 ·
What is the main advantage to the dual stage over a high-quality fail-safe aftermarket thermostat?
 

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What is the main advantage to the dual stage over a high-quality fail-safe aftermarket thermostat?
I remember a thread about this a while back, and I believe the consensus was that, since the dual stage thermostat opens more gradually (smaller valve first, then larger valve) the dual stage thermostat prevents the "shock" that can occur when a single stage thermostat suddenly opens, sending cold coolant in the radiator towards a warmed up engine. Perhaps someone else can chime in here...

You can probably get away with a cheaper thermostat from the parts stores. My point really was that there is no single temperature rating (i.e. 180F) that you'll be looking for, seeing as the stock thermostat does not have a single rating.

Also, I think if Mazda went to all of the trouble to put a sticker on the car specifically saying to use the dual stage thermostat, it's probably worth the $10-20 to go ahead and get the right one from the dealer. However it seems that getting some people on this board to visit the dealer for parts or a shop manual is like pulling teeth sometimes....

zlyricist said:
the dual stage thermo came with the non-turbo models as well?
Yes, I know all 2.2L engines use a two-stage thermostat. I'm not positive whether the nonturbos and turbos had different dual stagers, though - I'll check when I get home.
 

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Discussion Starter · #7 ·
Ok, thanks...I will get the Mazda unit, then...unless I can find a less expensive, aftermarket dual-stage thermo...
 

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I don't think the thermostat is very expensive at the dealer. I'll bet they have them in stock, too.

Also, I just checked my factory manual - the turbo and nonturbo OEM dual stage thermostats are identical.
 

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Discussion Starter · #10 ·
It ended up costing $23 for the thermo at the dealer, after tax. But, if it prevents major cooling / rad issues later on, it's cheap insurance in the long run.
 

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Discussion Starter · #11 ·
BTW, I got the entire system back flushed this weekend - paid a shop to do it, so they could also test the system for leaks. none were found, and the new thermostat was installed. The car is STILL not blowing heat through the vents (getting barely luke warm), although my unusually fast start-idle is now normal, it's heats up good, and no more temp fluctuations.

I have NOT checked my heater hoses SINCE the flush, but before it, both hoses were warm, but not especially hot - but if the thermo was stuck open, it may not have been heating up completely.

I will check both hoses, and see if they are hot later today. If they are not both hot, this suggests a problem with the heater core, correct? If so, I will plan to disconnect and plug the heater hoses (to lose as little coolant as possible), and use the hose to flush the core directly, and see if this improves things any.

I did a search, and found several threads referrign to the blend door, also. On the LX type controls, how do I go about checking, and adjusting if needed, this door?
 

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Discussion Starter · #12 ·
Ok, got back from my lunch break, and can say that after warming up, and running the heaters, etc...the rad hoses are hot enough to prevent sustained contact for more than a few moments. Neither of the heater hoses are this hot, but they are hot none-the-less. The upper hose is marginally warmer than the bottom hose, but not by much.

Any ideas, guys?

Should I try and flush the heater core again, or replace the heater hoses, or both...????
 

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have you checked for obstructions in the airflow path? when i pulled my skyline one out it was all but blocked up, having said that the car spent 10 years in japan. some of your US
cities are nearly that bad though.
 

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I say remove the glovebox and have a lookie back there - all of the control wires are back there and could be your culprit. I would first make sure the heater core is flushed though - something tells me it is still clogged.
 

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Discussion Starter · #15 ·
That's what I'm thinkning...
 

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usually if anyone has added any leak-sealing products... they have a tendancy to clog the heater core.... i had to replace mine b/c it wouldnt flow ANY coolant.

but there are other areas to check too... sometimes you can get corrosion and blockage in the intake manifold, which feeds the top(i think) of the heater core.

the heat you feel in those hoses could be little more than heat soak.... good luck
 
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Discussion Starter · #17 ·
Well, they were supposed to have done a pressurized back-flush of the entire system...

One suggestion my dad had was to drain out SOME of the coolant, add some flush to the system, and drive it like that for a VERY short time (no more than a couple hundred miles), to help break that crap up in there, and get it moving, THEN, reflush the system myself...I have a week & a half of vacation coming up starting next week...maybe I'll try it then...any ideas...
 

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Sounds like the heater core to me and I have the same exact problem. I bought a Fram back flush kit today that splices into the heater core line and lets you attach a garden hose to it so you can backflush the whole system.

That being said, I also picked up:


 
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