sTaLa

What do you think about gutting the thermostat so that it is always open?

Here's my situation. I had the add coolant buzzer last year. I thought it was the thermostat, so I changed it. But the buzzer came back after a week or two. I just kept adding coolant from time to time and it did the trick (I thougt the thermostat was not the source of the problem). And I stored the car for the winter.

I unstored the car two weeks ago, and the add coolant buzzer was still there. So I kept adding coolant from time to time, telling myself the coolant had to go somewhere, and that I would run into problems one day or another (by the way, the coolant tank was full, I mean overfilled because there is no overflow).

And my problem came today. I smelt sugar... The hose before the thermostat (right under the colant cap) was pressurized and leaking to its fitting. There was coolant all around the hose on the engine. My almost brand new thermostat does not open!!!

I'm kind of tired of this. What would happen if I removed the valve in the thermostat? Would the engine keep too cold? I do not drive my FC in winter, but it can get pretty cold in fall and spring (about 0-4 celcius).

Thanks guys!
Alex

KansasCityREPU

iTrader: (9)

You need the restriction that the thermostat supplies so that the coolant has a chance to cool down. Plus, it will take longer for the car to reach operating temp. If your concerned about quality, get a Mazda one.

sTaLa

I would not actually remove the thermostat, I would only stick it open. The one a bought was an OEM I got from a Mazda dealership...

I'll probably end up buying a new one as I will not want to wait hours to have some fun with the car...

Project88Turbo

iTrader: (22)

The factory service manual and the owner's manual both state the SEVERE ENGINE damage can result from running without a thermostat.

Vince

jjwalker

Thread after thread after thread go over this same subject over and over and over.

IT IS A BYPASS THERMOSTAT!

That mean that the thermostat allows coolant to circulate through the motor and bypass the radiator when cold. It provides a more even distribution of heat across the engine and helps warm the engine faster. When the thermostat opens to allow coolant to go through the radiator, it closes the bypass port.

If you gut, run without, or whatever with the thermostat, then you have coolant going through the rad AND bypass thing rad and recirculating.

You'll over heat, your engine will die. Also, you probably have a slightly leaking coolant O-ring on one of the rotors. It may not be ingesting coolant but rather pressure from exhaust entering the system. Consider that as well as you try to trouble shoot your cooling system issue.

sTaLa

Thanks for the info!

I searched a bit more and found out I was mistaken about the flow direction of the coolant.

Now, I joined a picture of the part that was pressurized. I really don't have any clue what could cause the problem!

If the flow was in the other direction, the thermostat not opening would be the cause. But now, since the coolant flows from the pump the the upper "pressurized" hose, the only thing I can think of is that hose is blocked somewhere???

Any ideas?

87FCTurboII

iTrader: (2)

You do know that the cooling system is supposed to pressurize once it warms up right? Water expands when it is heated.

jjwalker

The whole system will pressurize, whether the thermo is open or not.

The easiest way to tell you have exhaust gas leaking into the coolant is to warm the engine up, pull the hose out of the overflow. At idle, if you get smelly axhaust gass out of this tube, then you are in dire straits. Warm the car up, pull the overflow tube and put your thumb over it. If it immediatly pressurizes and smells like exhaust, you have a coolant seal issue which requires a rebuild. There are more exotic methods but my advice is the easy and reliable way to see.

RotaryRocket88

iTrader: (7)

The add coolant buzzer is coming on because you have not properly bled air out of the system, or the connection to the level sensor (top of radiator) is loose/broken/corroded/etc...

The cooling system is supposed to be under pressure. Increased pressure raises the boiling point of the water/coolant mix, so it will stay liquid while your engine is running. The radiator cap is rated at 12 lbs. (?), and will bleed coolant into the overflow tank if the pressure exceeds that level. Pressure is a GOOD thing.

duo2999

iTrader: (1)

get one. stant is major ftl

clokker

iTrader: (2)

Intuitively this makes sense but in fact, is totally fallacious.

You need a thermostat to regulate coolant flow to the engine and radiator so the temperature remains (relatively) constant, which it does by proportionately diverting flow either back into the block or through the heat exchanger...basically just like the single **** for your shower mixes hot and cold water to get the desired temp at the nozzle.
That's how a thermostat manages temps...it has absolutely fuckall to do with "slowing down" the water so it spends more time in the radiator.

If the thermostat acted as a "restriction" (instead of like the valve it actually is), consider this...what happens when you restrict an orifice in a closed loop fluid system?
You increase the pressure, that's what (somewhat analogous to your brake hydraulics).
What component of the system would be most affected by an increase in pressure due to reduced flow capacity...the waterpump, which would now have to work much harder to pump the coolant.
The pump would be hating life if this actually happened.

ericgrau

iTrader: (1)

You almost never need restriction for anything in any part of the car, nor is hardly any part intentionally designed with more restriction.

The cooling system can follow two paths after it leaves the engine: through the radiator or through the bypass. With no thermostat coolant flows through both for worse cooling, but this is acceptable in a pinch. The thermostat blocks the bypass when open so all the coolant goes through the radiator. When closed it blocks the radiator so all the coolant goes through the bypass. Besides better cooling, the thermostat is important for rapid warm-up because driving hard with a cold engine will cause accelerated engine wear. Always use OEM because the auto parts store ones are much less reliable and seem to allow less flow (or maybe are set hotter than their claimed temperature?). Change coolant and thermostat more often than recommended to be safe because overheats are the most common cause of engine failure in non-turbos.

Pressure comes naturally from heating up the coolant in an enclosed system. The pressure is regulated by the radiator cap which only needs to relieve excess pressure beyond its rating to do this; there's no need to create any restriction. A broken radiator cap could cause pressure to build and build without limit until a hose bursts, or they can leak or stick open causing zero pressure which causes other issues. Radiator caps are cheap; you may want to get one just in case.

If you want to properly bleed every last bit of air out of the system rather than struggling for a while to kinda-sorta-not do it, then get a lisle funnel. Search forums for more info on it, search google to buy one. Simple item, piece of cake to use. Air bubbles can cause erratic cooling system performance: things can be fine then suddenly a bubble can get stuck and restrict flow for poor cooling, or a bubble can hit the coolant sensor and make the car buzz at you b/c it thinks you have no coolant, etc., etc. The way to burp air without the Lisle funnel is to close the radiator cap and squeeze a hose repeatedly until air gets to the top. Then you add more coolant and repeat. As said this method is only partially effective and it's time consuming. From your description I dunno if you have any air bubbles but it would eliminate 1 more possible source of random confusion. I do it every time I change my thermostat or coolant.

sTaLa

Filler cap (13lbs) and OEM Thermostat are brand new.

Sure pressure is a good thing. But there was so much pressure in the hose that it spilled all over the engine. My stupid idea of adding coolant everytime the buzzer went off over-pressurized the overflow thank. And since there is no overflow on the overflow tank, pressure kept building.

At first the buzzer only went off on thight truns. But yesterday it would not sut up. Even went and I pulled over and turned off the engine, it took 30min to stop yelling.


I'll check if there is exhaust gaz in the overflow tank hose.
I'll lower the level of coolant in the overflow tank.
Then I'll try bleeding the system with the lisle funnel.
If that doesn't solve the problem, I'll replace the thermostat.

Other than that... I'll search a bit more...

clokker

iTrader: (2)

Why is there no overflow outlet on the expansion tank?
It absolutely needs one, system won't recover fluid without it.

FelixIsGod29X

iTrader: (50)

since there is no overflow on the overflow tank, pressure kept building.-- Make a over flow on the overflow tank or get the right overflow tank/cap.

At first the buzzer only went off on thight truns.---There is air in the system,bleeder screw is on the passenger side of the radiator towards the top.

If that doesn't solve the problem, I'll replace the thermostat.-- Ifs its a OEM stat from the dealer and you installed it properly then i wouldn't worry about it.

You need to vent the overflow, bleed the system of air, and get rid of ANY coolant leaks. Mine has been under 190 degress forever but one day it was going above 190. I had a TINY leak, once sealed it doesnt get as hot anymore. Any coolant leaks may cause air to get sucked in the system.

sTaLa

I took a look this morning now the engine has cooled. And there was almost no coolant in the upper hose (yesterday that hose was spilling all over the place by its fitting to the radiator cap).

From my understanding, the cooling of the colant should suck coolant from the overflow tank... but it didn't! There was almost no coolant when I removed the cap.

My pressure cap is brand new (but not OEM). Could it be the problem?

What I find really, really strange is that yesterday the coolant buzzer was yelling even if the upper hose was pressurized. I mean, if the upper hose is pressurized, there's is definitely coolant in the radiator and the sensor should be grounded?

Thanks!

jackhild59

iTrader: (7)

His coolant is accumulating in the overflow tank. The coolant 'all around the hose on the engine' is from a leak. That leak (and maybe others) is what is allowing the coolant to stay in the over flow tank, as it becomes a vacuum leak when the engine cools off.

The comments about the overflow tank having no overflow is unlikely and irrational.
The problem is the poster is bilingual and is struggling with a language barrier? If I am wrong, please post a picture so we can see what you are referring to.

Do a cooling system pressure test and find your leaks. Fix your leaks, fix your problem.

Good Luck.

-Crash-

You are most likely leaking coolant from a split line somewhere, but not at idle, I had this problem on my first rx7, mine was one of the small lines on the throttle body.

Just because there is pressure in the system doesn't mean there is coolant in the system. that is why your buzzer was yelling at you because it knows there is no actual water/coolant in the system, just pressure.

if you are leaking coolant, once you lose enough your engine starts running hotter which boils your coolant/water and in turn it becomes steam which will cause high pressure without having much water in the system.

get under your hood with the car warm, rev it up(with the throttle body) and look very closely at the lines for a leak, check the heater hoses, throttle body lines, and any other coolant lines (there are a lot more than you would think) it might be a drip or a spray of water.

here is a fun way to look for water leaks at night or if you have a garage, when its dark outside or with all the lights in your garage turned off do the above mentioned method but use a black light to look for leaks, 90% of coolants react to UV light (black light) and glow very bright.

Hope this helps.

ericgrau

iTrader: (1)

If you top off the cooling system through the metal cap the extra coolant will go into the overflow tank. Too much and it'll burst. Try siphoning your overflow down to "low" and then filling your cooling system at the metal cap. The extra should fill the overflow back up. Filling the overflow above "full" will likewise do the same.

Coolant buzzer means for whatever reason there is air where the coolant sensor is, or the coolant sensor is disconnected. It's connected to the wire at the top of the radiator. Having your coolant too low, air bubbles, steam from boiling, leaks letting air in (and coolant out) and a loose wire that detaches with the slightest movement are some examples of what could do this.

KansasCityREPU

iTrader: (9)

By design, the job of the thermostat is to either block flow or allow flow. It must restrict flow to be able to regulate flow. We are saying the same thing. It's just semantics.

jackhild59

iTrader: (7)

Except that in your version, the coolant is 'slowed down' in the radiator to increase cooling and in real life, it is 'sped up' in the radiator to increase cooling.

Other than being the exact opposite they are the same. So much semantics, so little time...

KansasCityREPU

iTrader: (9)

You're not getting the point. By design, the physical dimensions of the thermostat supply a certain amount of restriction even when it is open. When the thermostat is removed, the size of the opening increases. This is why in old hot-rod cars, they would remove the thermostat and replace it with a big washer. The washer would allow the coolest a little more time to sit in the radiator the be cooled.

clokker

iTrader: (2)

Imagine that every water molecule is a dump truck and it's heat load is carried in the bed.

The "washer/restrictor" theory assumes that each truck would move too quickly through the dump area (i.e., the radiator) to completely shed it's load unless traffic was slowed down.
So, instead of allowing 100 trucks per minute- who can only unload 50% of their heat in the time allotted- you install a restrictor (the washer) and now 50 trucks can fully unload in the same amount of time.
The end result however, is a total wash...the same amount of heat gets dumped every minute, no matter the method.

"Slowing down the water in the radiator" is an urban myth, plain and simple.

KansasCityREPU

iTrader: (9)

I guess for an old guy I can learn something. So, are you saying we sound all remove the thermostat to get better flow and therefore cooling?

beefhole

iTrader: (29)

I hate to get technical...
"Slowing down the water in the radiator" is an urban myth, plain and simple.
This is ambiguous.
Say you have a constant given flow of air through the radiator and you pass through coolant at a variable flow. You are saying that if you vary the GPM (I say GPM because I familiar with the term ) you take the SAME amount of heat out regardless?!

I may not be an engineer, but I deal with HVAC. I have to run calculations across heating coils to obtain proper air temperatures in systems. How do I vary the amount of heat taken/given to the system? I vary the flow of fluid through the coil. In this case, the coil is a radiator.

So... I am altering the flow (Gallons Per Minute) of water through the radiator and obtain different entering/leaving temperatures of both the water and air. But this whole time, it was just a myth?