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Discussion Starter · #1 ·
For those of you who think you...

For those of you who say you should only buy Mazda's OEM 2-stage $40 T-stat, and that a single stage will ruin the engine. I have a challange for you....PROVE IT.

Now I say a single stage will work just fine, and I intend to prove it.
I'll start by saying that I have had a single stage in my car for a year now with no problems. (so now Im alredy ahead with the proving process).
So what I want people to do is to post up what kind of T-stat you use (single stage or 2-stage) and have you had any problems since you put in the single stage T-stat? Have you noticed any difference between the single stage and the 2-stage as in performance and how well it maintains the cars running temp?

I'll start...

I have a 180 degree single stage T-stat. Ive had it for a year now and there is no problems. No I haven't noticed any difference between the 2-stage OEM and my new single stage T-stat and the running temp is the same as it always was.

Now its everybody elses turn. Lest put this 2-stage bull to rest and show everybody that its just a fancy way for mazda to make sure you only buy your T-stat from them, and that the 2-stage thing is also just somthing they did to justify the outrages $40 price tag.

Please only reply if you have had experience with both the 2-stage OEM T-stat and a single stage aftermarket T-stat. Those of you who have never tried a single stage T-stat because your stuck on buying nothing buy Mazda's 2-stager, you need not reply.
Also Please no replys about how this is wasting Bandwidth, because it won't. when the thread is tired out and no one is replying to it anymore the moderators will delete it like they do with all sorts of different threads before they put them in the search function. But If I do manage to prove that a single stage T-stat will work just fine I would expect this thread to stay in the search function, for the next person who comes along wondering if he/she can just use a single stage.
This is not intended for flamming or BSing, its purly intended to give the people who say you should only buy your T-stat from Mazda because its a 2-stage, to prove the reson why...because Im so sick of people saying this and that with no proff to back it up...kinda like the people who say the F2t's head has crappy flow...but yet nobody has flow tested yet. I want to make sure if people say its a delear only part that they give a reason and prove why and that its not just purly spectlation. I mean I gave a reason as to why I think a cheaper single stage is just fine (I have one in my car now with no problems) so its only fair that you people prove to me why I should only buy a $40 2-stage.

Methman

PS: I know some of you are thinking "but he said in the other thread that he had an aftermarket 2-stage T-stat"?? Well I made a mistake I removed my T-stat and found out that it is infact a single stage. Which I thought was great because it proves my point even better.
 

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After a quick google search, I found an article on dual stage thermostats.... suggested that on a specific Toyota engine, they had issues with "Temperature Overshoot". Since we have a turbo application, perhaps we need the same protection. Just putting this out on the table........
 

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Discussion Starter · #4 ·
Thanks Linoleum, For putting that on the table. See that is what I want...some real arguments with real proff not just spectulation.
Anyone else want to take a crack at it...mabey someone can take a crack at what linoleum stated and mabey take it further.
Sleepermx6..cnance are its a single stage..since most people agree that most aftermarket places don't carry 2-stage T-stat pluse if it was 2 stage then it would cost more.. So Im goin to take your post and put it in the catagory of, "I have a single stage and it works fine.
Anyone else?

Methman
 
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Dual stage thermostats help on cold starts by allowing the engine to warm up more before it gets full coolant flow. I believe that would help the people in the north east states and canada a lot.

I had an aftermarket single stage t-stat in my car, one day it decided to stop working. That $5 dollar part cost me a $200 head, plus another $100 in gaskets.

$300, or $17? Guess what I did the second time.
 
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Well, the typical result of a stuck thermostat is a blown headgasket and/or a cracked and warped head, I don't know how other experiences would differ ;-)

I have cracks from spark plug to exhaust valve in three cylinders, and two burned valves...

A reman head would have cost me $450, I got a used one from a member here.
 

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Bleh, when's the 2 stage begin to open? 180 degrees? How does that help with startup?

Besides, I live in FL, my coolant will never freeze, and certainly don't need to worry much about cold mornings.

However, my car is sitting in my driveway awaiting a new head gasket...and I've had a 180 degree thermostat in it for over a year. Previous owner had it replaced appearantly.
 

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i just baught a dual stage from ford for my mx-6.

how many people actualy know what a dual stage thermostat is? i'ts a thermostat with 2 seperate thermostat valves. one is smaller and opens at 85°C and the other valve opens at 88°C instead of just one valve that opens up at just one temp.

how i think it's better than a single stage is that your engine can maintain a more constant engine temperatures. this is achived by allowing just the small 85° valve to open and allow some cooler coolant (from the rad) to 'trickle in' instead of having one large valve open up and overcool the engine (with a rush of cold coolant from the rad). it'll be alot easier for your engine to maintain a temp of between 85-88° using two valves instead of just one. your engine will take less time to heat up using less fuel and creating less emissions.

now do i think it's really a big deal? no not really. a single stage t-stat will not kill your car upon installation or even for the life of your car - which by the way these things never seem to die - just crash.

i live in canada where it can get damn cold. it could make a difference when it's super cold out like -40° and your engine is at 88° then suddenly the t-stat opens up. presto 128° temp difference.

people be reasonable in this thread. i want to see what everyone else thinks too! not just another locked thread. if you have any thing else to add or question please do it in a respectable manner. thanks. kevin.
 

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I live in Corpus Chriti Texas. In the summer it can hit temperatures over 100 deg. One of the first things I did to the car when I bought it was flush the radiator, replace hoses & belts, & thermostat. Daily driver, avg. 350 miles per week. Single stage from Autozone & 1 year later, no problems. :D
 

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Cruising at 80mph on my last trip north. This is with a 180 degree thermostat, in the summer, with or without A/C.

 

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horsefluff, misinformation and thermodynamics

Methman said:
I have had a single stage in my car for a year now with no problems.
No "cracks from spark plug to exhaust valve" like FlySwat?

sleepermx6 said:
haven't had any problems for the past month yet
No "cracks from spark plug to exhaust valve" like FlySwat?

Illswyn said:
car is sitting in my driveway awaiting a new head gasket...and I've had a 180 degree thermostat in it for over a year
If that ain't a testimonial, I dunno what is!

drdemux said:
a single stage t-stat will not kill your car upon installation or even for the life of your car - which by the way these things never seem to die
Do a search on "head gasket" and then tell us that these things never seem to die. Or ask Illswyn.

car2nr69 said:
Single stage from Autozone & 1 year later, no problems.
No "cracks from spark plug to exhaust valve" like FlySwat?

Illswyn said:
Cruising at 80mph on my last trip north. This is with a 180 degree thermostat,
How's your head gasket?

Methman said:
Now its everybody elses turn. Lest put this 2-stage bull to rest and show everybody that its just a fancy way for mazda to make sure you only buy your T-stat from them, and that the 2-stage thing is also just somthing they did to justify the outrages $40 price tag.
Wrong.

Methman said:
Please only reply if you have had experience with both the 2-stage OEM T-stat and a single stage aftermarket T-stat. Those of you who have never tried a single stage T-stat because your stuck on buying nothing buy Mazda's 2-stager, you need not reply
After I pooched a bridge-ported 12A rotary (using a single-stage aftermarket thermostat rather than the 2-stage Mazda part), I consulted with Mazda Motors Canada (Warren Wheeler -- Manager of Warranty Claims).

By the way, this was not a warranty issue, it was a race car engine, so Mazda and Warren Wheeler had no stake in the issue. He had provided me with much, much valuable information on rotaries before and since.

The Mazda (2 rotor) rotary, for those of you unfamiliar with it, is sorta like a club sandwich -- the "bread" is end housings and intermediate housing made of cast iron and the "filling" is rotor housings made of aluminum.

Aluminum and cast iron have different co-efficients of thermal expansion (aluminum expands much more when heated) and have different rates of thermal conductivity (aluminum conducts heat much better than cast iron).

The 2-stage thermostat releases a smaller amount of coolant earlier and allows a more gradual normalization to operating temperatures and operating dimensions. A single-stage creates a more abrupt flow of coolant, engendering thermal shock and dimensional differences (cooling/shrinking rotor housings) which change the tension on the through bolts (analgous to head bolts on a piston engine) which changes the pressure on the rotor housing O-rings (analogous to head gasket on a piston engine).

Result: Coolant leaks into combustion chambers.

I built another 8 or so rotaries after that, (each time using the outrageously priced Mazda 2-stage thermostat) and they all survived, performed and prospered.

Coincidence? I think not. I'm kinda glad I invested in a 2-stage thermostat. Like FlySwat (& magik8), I think it's cheap insurance.

Now, does this parable have anything at all to do with our (cast iron block/aluminum head) F2 engine? Do the head gasket failures encountered by many, MANY users around here have anything to do with their saving a nickel on aftermarket thermostats? Does Methman know more about metallurgy and thermodynamics than the Mazda R&D engineers?

And am I part of the "2-stage bull" conspiracy to suck naîve F2/F2T owners into wasting money on a Mazda part?

Is Methman more clever (and thrifty) than FlySwat? Does he really need a copper head gasket? Or is that just a big scam, too? For myself, I plan to make my head gasket out of an old corn flakes box -- why waste $$$ on an "outrageous" OEM rip-off?
 

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no cracks, doesnt mean i wont get any, and besides as ive stated in many of my threads that i only drives the car about two miles a day which the car shouldn't get that hot in two miles of no traffic, on another foot note is if i wasnt selling the car then is the i would be more concerned about it.
 

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Illswyn said:
Cruising at 80mph on my last trip north. This is with a 180 degree thermostat, in the summer, with or without A/C.
Is that after 10 min of driving? Becasue when the car is warmed up that temp gauge should be around half not close to zero.

I think the argument for 2 stage is this. Since we have a cast iron block and aluminum head, their thermal properties are different. This being so the 2 stage thermostat gradually opens and slowly changes the temperature of the cooling system. The one stage it more abrubt and can cause the block and head to heat up and expand @ different rates. when that happens it stresses out the head gasket. Do that enough times and the gasket breaks. I'm going with a 2 stage from now on and I'm glad I know why (well I have always gone with what the bible told me on this issue.)
 

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Discussion Starter · #20 ·
SixSick6 said:
I'll ask you this methman, where does your needle sit at operating temperature?...mine hardly moves AT ALL, it basically stays at the first slash and never goes higher than a 1/8th of the way..very rarely does it even go past the first slash
the normal running temp for any MX-6 GT is right in the middle. Which is where mine sits, if your temp is really low all of the time I would be looking at you T-stat being stuck open, causing the temp to not make it to running temp. The reason why I say this is because when MY T-stat was completly out of my car it acted like what your saying bearly reaching past 1/2 way. I would check your T-stat and see if its not stuck open.

Methman
 
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