Black13B

iTrader: (1)

If any of you are having any cooling system problems, or feel you are running just a bit hot, I really recommend changing the thermostat with a Mazda OEM.

My cooling system is great, but it was a tad hot for my liking. I had never suspected the thermostat, moreso thinking the rad may have been in need of a cleaning or the internals had alot of buildup.

When installing the thermostat, ensure the jiggle-pin is at it's upmost position. Be sure there are no leaks.

For S4 guys, (hoping I get this right or else Icemark will come to get me), make sure when refilling the coolant to remove the top rad hose bleeder screw on the radiator.

I overlooked this, and had a bubble in the system without realizing it.

After some consideration, I realized I had forgot the bleeder screw.

After refilling with the bleeder screw removed, Topped everything up, and went for a little drive, I noticed MUCH cooler temperatures on the stock gauge.

For the most part, it runs 1/5th cooler at ALL times.

Anyways, just thought I'd recommend this to anyone having some cooling issues but wasn't sure where to start, using my own personal experience.

(moreso for the noobs who are doing searches.. this post does contain all the necessary words to attract them to the thread )

MasteRX

I second your opinion, and I bet you can get most others who have swapped from a Stant or whatever back to OEM to agree as well.

yearrgh

Thats a cardinal rule of thermostats. ALWAYS use OEM. One thing i can't figure out is that the jiggle pin is supposed to go at the top, but it won't fit in that way. the best i can do is about 3 o'clock.

Blue88GXL

try this. oem, aftermarket whatever. screw em both. Remove your thermostat. Rx7s run hotter than most any cars, and even with your fluid flowing to the radiator at all times, you still run at temps in the "running zone" of your temp gauge, but only barely. My 88 gxl runs about 2-3mm above the "C" on the temp gauge. Colder=more dense air=increased performance. Plus the stock thermostat has a clogging problem, and if it clogs you will overheat and blow off some hoses on the back of your efi that have silicon connects and will be annoying or costly to fix...or both.

klrbee7

iTrader: (8)

Cool im going to try this. I never took the big screw from the radiator when i filled it with coolant and water. May this will fix my problem. i will let you know if it works.. coz i have a brand new rebuilt engine ang i used the old radiator that came with the car when i bought it. will post again tomorrow..

Mr. Gadget

Blue, thats a bad idea, running with no stat will cause hotspots within the engine.

SleeperZzZ

yea i heard the running no thermostat was a bad idea

Black13B

iTrader: (1)

NEVER run the engine without a thermostat.

Tofuball

Yay, as if our engines could take any LONGER to warm up on cold mornings

Aaron Cake

iTrader: (1)

This is VERY bad advice. Running without a thermostat is a sure way to run an engine too hot. You wonder why? Because without it, the coolant circulates too fast to transfer heat from the engine block. Coolant temperatures will be lower, while actual engine temps will be much higher. This means that your guage will be reading low.

Also, what are you talking about "blow off some hoses on the back of your efi"? There are no stock silicone hoses in the RX-7, and there are no coolant lines running to the ECU. I think you're pretty confused about something.

Coolant temps also have nothing to do with air temps...

klrbee7

iTrader: (8)

Im having problems with my temp. I have a new rebuilt engine. I said i while ago i will try and take the bleeder screw out of my radiator.

since i have all the coolant and water in my Rad. Can i just take and Screw out and put it back in? or do i have to drain everything ?

thanks

JP

Black13B

iTrader: (1)

Its the bleeder screw at the top rad hose.

Do you have an S4 rad?

after removing the bleeder screw, my 'topped up' fluids all drained into the rad..

Fill @ the fill neck until some of the fluid begins to seep from the bleeder screw. Reinstall the screw and top up fluid.

silverrotor

iTrader: (1)

In regards to bleeding your system of air - after you bleed from screw found at the Radiator, you may want to disconnect the one end of the cooling hose (found at the Thermowax) and proceed to pour Coolant Into the Filler neck until coolant flows out of this end of the hose. Doing this, ensures that portion of the cooling route Is free of air, thus free of air from the whole system.

Icemark

Probably the worst advice I have seen all week.

#1 one of the worst possible things you can do to a rotary is to remove the thermostat. Hell even 20B IMSA GTO cars used at least the thermostat body with the valve cut off, just to restrict the flow.

Because as Aaron mentioned without the restriction, the coolant flows way way too fast to effectively cool the engine, and you will end up with bad hot spots, leading to premature engine failure. You need the coolant to flow slow enough to absorb the heat. Without the thermostat the coolant flows way too fast.

If you are truely convinced you know more than 99% of the rotary engine tuners and builders out there, well alone Mazda's engineers own experience, then at very least, put in the thermostat body in.

#2 And the OEM design prevents the clogging that you mention. Even when the thermostat completely locks and fails, the system will bleed through, and not "blow off some hoses". Sure there is the potential of overheating when a thermostat fails, but that is what the water temp gauge is for.

klrbee7

iTrader: (8)

Thanks guys i tried it. but i think my rad is bad. I did it step by step, and i took the Thermostat out to make sure that my thermostat is not bad. then i drove it arround and my heat is above normal. so i think it's my radiator. Thanks again

JP

Blue88GXL

Ok guys, apparently taking the thermostat out is a bad idea...so tomorrow i think i shall put mine back in. But, a few things.

1. i never said that i truely believe that i know more about rotaries than 99% of people out there. Dont make **** up.

2. About the silicon hoses. I never said silicon hoses, check it. I said hoses w/silicon connects...as in, they are connected with silicon. And yes, that is true. And yes, your thermostat can most definetly clog up, stop up completely, and the built pressure can and will blow these hoses off the back of your engine. I am 110% sure that this is accurate, and can and will happen. Why? because it definitely happened to my car. It overheated bc the thermostat clogged and built up pressure and blew the silicon from the back of the motor. It is now replaced with metal connectors. This was assesed and fixed by a Mazda certified Rotary mechanic, and i am sure he knows more than the rest of us here. (not saying that i do, but he does). And so yes, there are silicon connected hoses, and yes the thermostat can clog and they can be blown off. End of story.

3. Where did you get coolant lines running to the ECU from? when the hell did i say that ****? oh yea, i didnt.

JPA

My 88 vert's gas mileage went from 10mpg to 17 after I replaced the rad and had the original thermostat replaced.

One of the 1st questions they asked me was about gas mileage cause I guess the cold coolant tells the ecu to run it rich???

Now it's running 1/3 - 1/2 on the guage with AC on in traffic, great mileage and it's 95 degrees out.

ilike2eatricers

Honestly from all the horror stories I have heard on the forum I would say not many "Mazda certified rotary mechanics" are qualified to work on a rotary. There are of course exceptions.

c-squared

There is no stock silicon in an RX-7 in the hoses, or clamps. There is most likely silicon in the chips of the ECU.

There is no silicone in any part of the engine bay of a stock FC. Your mechanic did not tell you fact.

The stock waterpump, running into a completely closed system (completely clogged thermostat), is not efficient enough to create enough pressure to blow the stock good condition hoses, coolant gaskets, engine o-rings, or coolant temp sensors. The water pump is not a pressure pump, it is efficient for flow.

Your hoses blew b/c they were conatminated from a petroleum product, despite what your mechanic told you.

Mechanics are not always honest to their clients. They often tell their customers the "easiest to understand" or "sounds the best" story. This is likely what happened to you.

You cannot be 110% sure of anything. This is 10% higher than the theoretical maximum amount. Also, human nature does not allow anything to be believed to levels of perfection. This is called reserved doubt,; it presents the possibility that anything we hear can be questioned.

Lastly, Mazda mechanics are trained to know how to fix cars, not how they work, what the parts are made of, or potential flaws in design, so don'y take their words for gospel.

Blue88GXL

ok, ok. Well whatever the case, that was what i was told and thought i understood. Im not questioning your knowledge, cause i know you know more about it than i do. At whatever rate, that was his story and i thought that that was what happened. I didnt know that no thermostat was a horrible idea, and i just finished putting one back into my car...quesiton. i think the stock temp thermostat is like 170...is it cool to run a 160 or is that a bad idea (i cant remember what the stock thermostats temp was, but i think the one i just put in is 10-20 degrees cooler)

HAILERS

Somewhere around 180/162 degrees F. It's in the manual, Cooling Section.

chris1234p

Wow c-squared I learned alot from your post.

mac_dad6

mazda racing actually reccomends in race used cars to gut the thermostat but dont completely remove it. some resistance is absolutely neccessary for proper cooling. i dont think i would run a gutted thermostat on a street car though

Icemark

As mentioned by C-squared, the thermostat can't plug and blow hoses (or anything else for that matter). If it did, then everytime you started the car cold when the thermostat was closed you would blow hoses. Who ever told you that a clogged thermostat would blow hoses, is clueless on the rotary engine.

and what hose connects with a silicon connect??? There sure are not any on a FC. What silicon can you possible mean when you say Could you possible mean the gasket??? I doubt it because then you said:
I think your "Mazda certified Rotary mechanic" is about as clueless as they come and was just feeding you some BS that he thought you wanted to hear.

HAILERS

OOOOps. I wrote 180/162 F and meant to write 180/182. But that would be wrong.

I just looked in the fsm and it say it begins to open 177-182 F and is fully open at 203F.