But why??? I'm overheating
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But why??? I'm overheating
I don't get it I've flushed the coolant changed my thermostat and upgraded to a mishimoto fan and shroud. Car seemed to cool fine for a week or two. Then I changed the spark plugs and its over heating again. Also I noticed looking at my NC miata there is foam bellow radiator. But not in my rx8. I read something about foam keeping the car cool. Anyways wtf is my car getting so hot!!! I feel like the stock components should keep the car cool. I'm so worried about blowing my seals. Also I took off the engine cover in hopes of cooling. But it's not any better. Should I even be worried? These temps are being taken from right below the thermostat.
#2
Smoking turbo yay
There is supposed to be foam all around the radiator to make sure the air is forced through the radiator.
The difference the engine cover will make is pretty minimal.
Don't drive the car until you fix it.
The difference the engine cover will make is pretty minimal.
Don't drive the car until you fix it.
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200.mph (10-22-2019)
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200.mph (10-22-2019)
#4
Water Foul
A few unvarnished thoughts:
1. Mishimoto parts are generally over-priced junk. We recommend Koyo and CSF on this site for good reasons.
2. Have you verified the fans are turning on in the proper sequence and running at the proper speeds?
3. Have you verified all air is out of the system? The RX-8 is not the easiest car to burp for some reason.
4. Have you verified the thermostat is working? Is it oriented properly (jiggler up)? Is it a quality brand like Mazda, AC Delco, Stant, or Gates?
5. Do you have the undertray in place? It is critical for directing air into the radiator.
6. Did you foam at least 3 sides of the radiator with pipe insulation?
7. Does it overheat at idle? If so, that absolutely should not happen. The fans should keep temps reasonable.
8. What coolant are you using and in what proportion glycol to distilled water?
1. Mishimoto parts are generally over-priced junk. We recommend Koyo and CSF on this site for good reasons.
2. Have you verified the fans are turning on in the proper sequence and running at the proper speeds?
3. Have you verified all air is out of the system? The RX-8 is not the easiest car to burp for some reason.
4. Have you verified the thermostat is working? Is it oriented properly (jiggler up)? Is it a quality brand like Mazda, AC Delco, Stant, or Gates?
5. Do you have the undertray in place? It is critical for directing air into the radiator.
6. Did you foam at least 3 sides of the radiator with pipe insulation?
7. Does it overheat at idle? If so, that absolutely should not happen. The fans should keep temps reasonable.
8. What coolant are you using and in what proportion glycol to distilled water?
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gwilliams6 (11-04-2019)
#5
///// Upscale Zoom-Zoom
summary: make sure your system coolant pressure is good by checking your cap, coolant level, and coolant quality.
Pressure test your radiator coolant overflow tank cap and make sure at max operating temperature that your coolant is in between the min/max lines on the overflow tank. Issue 1: If it is not holding pressure (13 psi at max coolant temp conditions), then the boiling point of the FL-22 coolant is lower and (the boiling coolant in hot spots) significantly lowers the heat transfer surface area leading to overtemps. Issue 2: Too little coolant volume in the overflow tank will lead to lower system pressures at op temperature leading to lower coolant boiling points. Issue 3: Wrong coolant type/mixture and air bled from system (SD stated this above).
Occasional gurgling (of coolant flow as heard from the driver' seat) at idle is normal
Pressure test your radiator coolant overflow tank cap and make sure at max operating temperature that your coolant is in between the min/max lines on the overflow tank. Issue 1: If it is not holding pressure (13 psi at max coolant temp conditions), then the boiling point of the FL-22 coolant is lower and (the boiling coolant in hot spots) significantly lowers the heat transfer surface area leading to overtemps. Issue 2: Too little coolant volume in the overflow tank will lead to lower system pressures at op temperature leading to lower coolant boiling points. Issue 3: Wrong coolant type/mixture and air bled from system (SD stated this above).
Occasional gurgling (of coolant flow as heard from the driver' seat) at idle is normal
Last edited by wannawankel; 10-22-2019 at 02:07 PM.
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summary: make sure your system coolant pressure is good by checking your cap, coolant level, and coolant quality.
Pressure test your radiator coolant overflow tank cap and make sure at max operating temperature that your coolant is in between the min/max lines on the overflow tank. Issue 1: If it is not holding pressure (13 psi at max coolant temp conditions), then the boiling point of the FL-22 coolant is lower and (the boiling coolant in hot spots) significantly lowers the heat transfer surface area leading to overtemps. Issue 2: Too little coolant volume in the overflow tank will lead to lower system pressures at op temperature leading to lower coolant boiling points. Issue 3: Wrong coolant type/mixture and air bled from system (SD stated this above).
Occasional gurgling (of coolant flow as heard from the driver' seat) at idle is normal
Pressure test your radiator coolant overflow tank cap and make sure at max operating temperature that your coolant is in between the min/max lines on the overflow tank. Issue 1: If it is not holding pressure (13 psi at max coolant temp conditions), then the boiling point of the FL-22 coolant is lower and (the boiling coolant in hot spots) significantly lowers the heat transfer surface area leading to overtemps. Issue 2: Too little coolant volume in the overflow tank will lead to lower system pressures at op temperature leading to lower coolant boiling points. Issue 3: Wrong coolant type/mixture and air bled from system (SD stated this above).
Occasional gurgling (of coolant flow as heard from the driver' seat) at idle is normal
A few unvarnished thoughts:
1. Mishimoto parts are generally over-priced junk. We recommend Koyo and CSF on this site for good reasons.
2. Have you verified the fans are turning on in the proper sequence and running at the proper speeds?
3. Have you verified all air is out of the system? The RX-8 is not the easiest car to burp for some reason.
4. Have you verified the thermostat is working? Is it oriented properly (jiggler up)? Is it a quality brand like Mazda, AC Delco, Stant, or Gates?
5. Do you have the undertray in place? It is critical for directing air into the radiator.
6. Did you foam at least 3 sides of the radiator with pipe insulation?
7. Does it overheat at idle? If so, that absolutely should not happen. The fans should keep temps reasonable.
8. What coolant are you using and in what proportion glycol to distilled water?
1. Mishimoto parts are generally over-priced junk. We recommend Koyo and CSF on this site for good reasons.
2. Have you verified the fans are turning on in the proper sequence and running at the proper speeds?
3. Have you verified all air is out of the system? The RX-8 is not the easiest car to burp for some reason.
4. Have you verified the thermostat is working? Is it oriented properly (jiggler up)? Is it a quality brand like Mazda, AC Delco, Stant, or Gates?
5. Do you have the undertray in place? It is critical for directing air into the radiator.
6. Did you foam at least 3 sides of the radiator with pipe insulation?
7. Does it overheat at idle? If so, that absolutely should not happen. The fans should keep temps reasonable.
8. What coolant are you using and in what proportion glycol to distilled water?
#8
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summary: make sure your system coolant pressure is good by checking your cap, coolant level, and coolant quality.
Pressure test your radiator coolant overflow tank cap and make sure at max operating temperature that your coolant is in between the min/max lines on the overflow tank. Issue 1: If it is not holding pressure (13 psi at max coolant temp conditions), then the boiling point of the FL-22 coolant is lower and (the boiling coolant in hot spots) significantly lowers the heat transfer surface area leading to overtemps. Issue 2: Too little coolant volume in the overflow tank will lead to lower system pressures at op temperature leading to lower coolant boiling points. Issue 3: Wrong coolant type/mixture and air bled from system (SD stated this above).
Occasional gurgling (of coolant flow as heard from the driver' seat) at idle is normal
Pressure test your radiator coolant overflow tank cap and make sure at max operating temperature that your coolant is in between the min/max lines on the overflow tank. Issue 1: If it is not holding pressure (13 psi at max coolant temp conditions), then the boiling point of the FL-22 coolant is lower and (the boiling coolant in hot spots) significantly lowers the heat transfer surface area leading to overtemps. Issue 2: Too little coolant volume in the overflow tank will lead to lower system pressures at op temperature leading to lower coolant boiling points. Issue 3: Wrong coolant type/mixture and air bled from system (SD stated this above).
Occasional gurgling (of coolant flow as heard from the driver' seat) at idle is normal
A few unvarnished thoughts:
1. Mishimoto parts are generally over-priced junk. We recommend Koyo and CSF on this site for good reasons.
2. Have you verified the fans are turning on in the proper sequence and running at the proper speeds?
3. Have you verified all air is out of the system? The RX-8 is not the easiest car to burp for some reason.
4. Have you verified the thermostat is working? Is it oriented properly (jiggler up)? Is it a quality brand like Mazda, AC Delco, Stant, or Gates?
5. Do you have the undertray in place? It is critical for directing air into the radiator.
6. Did you foam at least 3 sides of the radiator with pipe insulation?
7. Does it overheat at idle? If so, that absolutely should not happen. The fans should keep temps reasonable.
8. What coolant are you using and in what proportion glycol to distilled water?
1. Mishimoto parts are generally over-priced junk. We recommend Koyo and CSF on this site for good reasons.
2. Have you verified the fans are turning on in the proper sequence and running at the proper speeds?
3. Have you verified all air is out of the system? The RX-8 is not the easiest car to burp for some reason.
4. Have you verified the thermostat is working? Is it oriented properly (jiggler up)? Is it a quality brand like Mazda, AC Delco, Stant, or Gates?
5. Do you have the undertray in place? It is critical for directing air into the radiator.
6. Did you foam at least 3 sides of the radiator with pipe insulation?
7. Does it overheat at idle? If so, that absolutely should not happen. The fans should keep temps reasonable.
8. What coolant are you using and in what proportion glycol to distilled water?
#9
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Some generic coolants like that contain 2EHA which will eat your coolant seals over time. It's a rotary specific problem. Use Mazda FL22 only or make very sure this coolant doesn't contain 2EHA.
By the looks of it the stock clamp has compressed the hose? It looks deformed, you may want to replace it.
So the only thing unaccounted for is the proper function of both fans. Can you confirm they both turn on and both go to high speed above 210 or something like that?
I don't think a 3rd thermostat is necessary if the 2nd one didn't fix the problem.
By the looks of it the stock clamp has compressed the hose? It looks deformed, you may want to replace it.
So the only thing unaccounted for is the proper function of both fans. Can you confirm they both turn on and both go to high speed above 210 or something like that?
I don't think a 3rd thermostat is necessary if the 2nd one didn't fix the problem.
#10
Smoking turbo yay
It's just that head gaskets are much easier and cheaper to replace than coolant seals.
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Loki (10-28-2019)
#11
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Some generic coolants like that contain 2EHA which will eat your coolant seals over time. It's a rotary specific problem. Use Mazda FL22 only or make very sure this coolant doesn't contain 2EHA.
By the looks of it the stock clamp has compressed the hose? It looks deformed, you may want to replace it.
So the only thing unaccounted for is the proper function of both fans. Can you confirm they both turn on and both go to high speed above 210 or something like that?
I don't think a 3rd thermostat is necessary if the 2nd one didn't fix the problem.
By the looks of it the stock clamp has compressed the hose? It looks deformed, you may want to replace it.
So the only thing unaccounted for is the proper function of both fans. Can you confirm they both turn on and both go to high speed above 210 or something like that?
I don't think a 3rd thermostat is necessary if the 2nd one didn't fix the problem.
#12
Water Foul
A new set of stock fans pull an impressive amount of CFM. Aftermarket fans usually under-perform the stock fans. The ones that are proven to be at least as good are 2 models of FAL shrouds. I don't know the specs on your Mishimoto fans, but I suspect they are not as good as a good set of OE replacement fans and probably under-perform the rated specs. So, being new does not necessarily mean anything.
The only trouble with the stock fans is that they slow down over time, and/or they have debris (such as airbox grommets) fall in them and burn them out.
The only trouble with the stock fans is that they slow down over time, and/or they have debris (such as airbox grommets) fall in them and burn them out.
#13
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The fans might be new but they run on relays. Maybe there's a problem there.
The fan logic is roughly this:
AC off:
- at 190F start fan 1 on low speed
- at 205 start both fans on high speed
AC on:
- start fan 2 whenever compressor is engaged
- at 190F also start fan 1 at low speed
- at 205 both fans on high full time
Someone can correct me, I'm going by memory.
The gist of it is that if the fans are only turning on when you hit 210ish, but not at 190, the car is heatsoaking, and AC is just making it worse.
See if your car behaves that way^^.
The lower temp thermostat shouldn't make any difference because by the time you get to 200, its full open anyway.
Do you see bubbles in the coolant overflow while the car is running? Start it cold with the cap off to see better, and it let it warm up.
The fan logic is roughly this:
AC off:
- at 190F start fan 1 on low speed
- at 205 start both fans on high speed
AC on:
- start fan 2 whenever compressor is engaged
- at 190F also start fan 1 at low speed
- at 205 both fans on high full time
Someone can correct me, I'm going by memory.
The gist of it is that if the fans are only turning on when you hit 210ish, but not at 190, the car is heatsoaking, and AC is just making it worse.
See if your car behaves that way^^.
The lower temp thermostat shouldn't make any difference because by the time you get to 200, its full open anyway.
Do you see bubbles in the coolant overflow while the car is running? Start it cold with the cap off to see better, and it let it warm up.
#15
Water Foul
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A new set of stock fans pull an impressive amount of CFM. Aftermarket fans usually under-perform the stock fans. The ones that are proven to be at least as good are 2 models of FAL shrouds. I don't know the specs on your Mishimoto fans, but I suspect they are not as good as a good set of OE replacement fans and probably under-perform the rated specs. So, being new does not necessarily mean anything.
The only trouble with the stock fans is that they slow down over time, and/or they have debris (such as airbox grommets) fall in them and burn them out.
The only trouble with the stock fans is that they slow down over time, and/or they have debris (such as airbox grommets) fall in them and burn them out.
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I'll be that guy... Mishimoto is shitty garbage... also oem fans are around 1235cfm....
The only fan that I would consider an upgrade from oem is FAL420 or 480.
Like those above said put in the foam around the rad, and if you can get the fans to turn on at a lower temp than oem( tune or controller mod) . Oh and make sure that they are sucking air into the engine bay and not trying to blow it out.
The only fan that I would consider an upgrade from oem is FAL420 or 480.
Like those above said put in the foam around the rad, and if you can get the fans to turn on at a lower temp than oem( tune or controller mod) . Oh and make sure that they are sucking air into the engine bay and not trying to blow it out.
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I'll be that guy... Mishimoto is shitty garbage... also oem fans are around 1235cfm....
The only fan that I would consider an upgrade from oem is FAL420 or 480.
Like those above said put in the foam around the rad, and if you can get the fans to turn on at a lower temp than oem( tune or controller mod) . Oh and make sure that they are sucking air into the engine bay and not trying to blow it out.
The only fan that I would consider an upgrade from oem is FAL420 or 480.
Like those above said put in the foam around the rad, and if you can get the fans to turn on at a lower temp than oem( tune or controller mod) . Oh and make sure that they are sucking air into the engine bay and not trying to blow it out.
#20
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What do you mean by "the fan turn on thresholds?" My fans turn on and off just as the manual says. At the intervals listed in the manual. I put foam in and wow! What a difference in temperature while moving. Unfortunately wasnt my solution though. I'm beginning to think my radiator could just be corroded or something because far left of the radiator/transmission cooler are at decent temps. But the right side is constantly higher temps. The temps measured on the right end of the radiator/transmission cooler line up with temps I'm getting from my obd scan tool.
Would you say the side where hot water comes in from the thermostat is the one that's higher, and the side where cooled coolant returns to the engine is the cooler one?
What kind of temperature difference are we talking? How hot is the return line compared to the radiator entry line?
Going further down the list of possible causes, ado you see bubbles in the coolant overflow tank while the engine is running? (do not open it when hot, start the cold car with the reservoir open and let it warm up)
#21
Moder8
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Much of it was covered already, but here is something...
https://www.rx8club.com/series-i-tro...o-i-do-258334/
Regarding Foam, it directs air at speed, it also keeps the hot engine compartment air from flowing back around the radiator when stopped and the fans are running. If hot air flows back around, you are stuck trying to cool the engine with 160 degree air.
https://www.rx8club.com/series-i-tro...o-i-do-258334/
Regarding Foam, it directs air at speed, it also keeps the hot engine compartment air from flowing back around the radiator when stopped and the fans are running. If hot air flows back around, you are stuck trying to cool the engine with 160 degree air.
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Nice work on the foam. I meant the on/off temps, so I guess that checks out.
Would you say the side where hot water comes in from the thermostat is the one that's higher, and the side where cooled coolant returns to the engine is the cooler one?
What kind of temperature difference are we talking? How hot is the return line compared to the radiator entry line?
Going further down the list of possible causes, ado you see bubbles in the coolant overflow tank while the engine is running? (do not open it when hot, start the cold car with the reservoir open and let it warm up)
Would you say the side where hot water comes in from the thermostat is the one that's higher, and the side where cooled coolant returns to the engine is the cooler one?
What kind of temperature difference are we talking? How hot is the return line compared to the radiator entry line?
Going further down the list of possible causes, ado you see bubbles in the coolant overflow tank while the engine is running? (do not open it when hot, start the cold car with the reservoir open and let it warm up)
pictures are top hose/bottom hose on start
Then its top hose/bottom hose after warm up. Lower than mid on temp gauge.
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#25
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"Doing its job" isn't the same as "doing its job well enough".
I would check the temperatures horizontally across the radiator. The radiator has a series of vertical channels that sink heat to air via horizontal fins. If some of the vertical channels are blocked or otherwise restricted, no coolant will travel those and you'll lose cooling capacity. It may work well enough until you stress the engine at which point heat output will overwhelm the radiator's ability to reject the heat to air.
I would check the temperatures horizontally across the radiator. The radiator has a series of vertical channels that sink heat to air via horizontal fins. If some of the vertical channels are blocked or otherwise restricted, no coolant will travel those and you'll lose cooling capacity. It may work well enough until you stress the engine at which point heat output will overwhelm the radiator's ability to reject the heat to air.