Why did Mazda sell the RX-8 with an incompetent cooling system?
08-26-2015, 09:14 AM
#26
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My car is a 2012. Every component on this car is new. That's why I started this thread in the first place. We have 2010 R3s with 12,000 miles that hit 226F while idling for 20 mins. I don't think EVERY cars cooling system is failing.
08-26-2015, 09:19 AM
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Ah, ok, that changes a few things.
Though I thought 2011 was the last year for everywhere except Japan, which had a very limited run of a few hundred 2012s. I guess you got one shipped?
Though I thought 2011 was the last year for everywhere except Japan, which had a very limited run of a few hundred 2012s. I guess you got one shipped?
08-26-2015, 09:24 AM
#28
You gonna eat that?
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08-26-2015, 09:29 AM
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Yeah I got mine off an auction in Japan. Was a royal pain, but it's finally here. It sucks when I have to deal with cooling issues on a (reasonably) new sports car that I paid a fortune to get!
08-26-2015, 04:27 PM
#31
Something that has helped me cool the car down before putting it in the garage is the fans on low mod. This easy mod allows you to make sure both fans are always running at least on low speed (or medium if you like) regardless of what the ECU wants to do. This probably doesn't do anything when you are sitting in traffic with the A/C on (see fan control description below), but it does seem to affect cooling when the car is moving more than ~10mph, but too slowly to force much air through the radiator, and when the A/C is off.
Thanks for posting that table. It seems different from the Series I fan operation logic. I only remember seeing 3 relays for Series I. May be a stupid questions, but what is the maximum speed at which the ECU will operate the fans?
08-26-2015, 10:11 PM
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Why did Mazda sell the RX-8 with an incompetent cooling system?
Yeah I'd like to know the speed too. And does anyone know the maximum vehicle speed that the fans stay on? 20mph?
08-26-2015, 10:11 PM
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Why did Mazda sell the RX-8 with an incompetent cooling system?
216 was the nominal high once heat soaked in normal conditions. I have seen around 220 peak a couple of times in 3 years in extreme conditions (ambient temp > 105). Sorry for the lack of clarity, but I didn't feel like typing a thesis on my car's temps, so I lazily used your number.
The fans on low can become a restriction at speeds above 30mph, which is why I put mine on a switch. I turn them on when sitting in traffic and when creeping through residential areas at 15-20mph. I also turn them on when exiting the track and driving around the pits and paddock. I only plan to use the fans in the summer here. It is an easy and almost free mod that may help you in certain conditions. You can wire up a switch and tie it up under your dashboard to test the mod and see if it works for you without doing any permanent damage to your car. You can also wire them to run at medium or high if you like, which would effectively simulate a fan upgrade.
I still think you are operating under a false premise here. Most 8 owners who live in hot climates pay no attention at all to their cooling systems while driving them all summer long in high to exreme heat and have no heat-related problems. Also, keep in mind that the membership on this board is mostly enthusiasts and people having problems. That does not accurately represent the 8-owning public at large. Most 8 owners have no idea this board exists.
The fans on low can become a restriction at speeds above 30mph, which is why I put mine on a switch. I turn them on when sitting in traffic and when creeping through residential areas at 15-20mph. I also turn them on when exiting the track and driving around the pits and paddock. I only plan to use the fans in the summer here. It is an easy and almost free mod that may help you in certain conditions. You can wire up a switch and tie it up under your dashboard to test the mod and see if it works for you without doing any permanent damage to your car. You can also wire them to run at medium or high if you like, which would effectively simulate a fan upgrade.
I still think you are operating under a false premise here. Most 8 owners who live in hot climates pay no attention at all to their cooling systems while driving them all summer long in high to exreme heat and have no heat-related problems. Also, keep in mind that the membership on this board is mostly enthusiasts and people having problems. That does not accurately represent the 8-owning public at large. Most 8 owners have no idea this board exists.
Ok a switch fixes the issue. You're correct. Fans on high would be pretty good for me. More cooling is always good!
Again, you are correct. Most 8 owners have no idea that this exists. But we Sri Lankans love our cars. We're the kind of guys who'd die for our cars
So you're saying that 220F is SAFE for these cars? Then what's with RIWWP posting on the new owners thread that our coolant seals are good only up to 220F? Did he take it from 9k's builder too? 220F seems to be the general rule number around here. Everyone took it from that one builder? I thought there are plenty of cars that died from living in the 220F+ range.
Last edited by Nisaja; 12-11-2015 at 10:46 PM.
08-26-2015, 11:30 PM
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Why did Mazda sell the RX-8 with an incompetent cooling system?
Originally Posted by ouimetnick
The cooling system in my car is original (2004). Car never starts to overheat. I've seen it hit 210F in 95F with the AC on, but never higher than that.
08-26-2015, 11:33 PM
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Why did Mazda sell the RX-8 with an incompetent cooling system?
Originally Posted by 9krpmrx8
You can pull the radiator without breaking the nipple, you just have to not take that hose off the radiator and disconnect it at the coolant reservoir. Yours is a 2012, I doubt it is that fragile yet. As for the price, well if you want an improvement you have to pay for it. Pusher fans is a bad idea, no need for that.
08-26-2015, 11:35 PM
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Why did Mazda sell the RX-8 with an incompetent cooling system?
Originally Posted by ouimetnick
Depends on the traffic. Sometimes 5-10 minutes if the train is coming. I just have my OBD II thing paired with my phone, and monitor the thing like a hawk.
08-26-2015, 11:58 PM
#39
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I looked at the FAL 420 on Amazon. It says it won't fit our cars. Do you have the same?
Attachment 210561
Attachment 210561
It fits. See the first post in my build thread. The 480 has larger motors and still fits with plenty of room. Jegs also makes their own version with similar specs to the 420 for cheaper.
08-27-2015, 08:14 AM
#40
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I've missed your reply. 220 in 105 is still pretty high. Was that with the stock rad? 216 is a number. I can live with. I'm one of those guys who'd like to see the coolant temp below 200F all the time, so if something goes wrong, I have plenty of headroom to do something about it.
Ok a switch fixes the issue. You're correct. Fans on high would be pretty good for me. More cooling is always good!
Again, you are correct. Most 8 owners have no idea that this exists. But we Sr Lankans love our cars. We're the kind of guys who'd die for our cars
So you're saying that 220F is SAFE for these cars? Then what's with RIWWP posting on the new owners thread that our coolant seals are good only up to 220F? Did he take it from 9k's builder too? 220F seems to be the general rule number around here. Everyone took it from that one builder? I taught there are plenty of cars that died from living in the 220F+ range.
Ok a switch fixes the issue. You're correct. Fans on high would be pretty good for me. More cooling is always good!
Again, you are correct. Most 8 owners have no idea that this exists. But we Sr Lankans love our cars. We're the kind of guys who'd die for our cars
So you're saying that 220F is SAFE for these cars? Then what's with RIWWP posting on the new owners thread that our coolant seals are good only up to 220F? Did he take it from 9k's builder too? 220F seems to be the general rule number around here. Everyone took it from that one builder? I taught there are plenty of cars that died from living in the 220F+ range.
I realize what the stickies say, and like you, I don't want to see my coolant temperatures much above 200 for very long. I'm not an expert, so I can't comment further, other than to say I have no signs of coolant in my oil at this point (2011 with 32K very hard miles).
Before you spend the time and money on a fan upgrade, try putting a switch on your fans. At the very least, it will tell you if the fan upgrade is worth it. And, you may find you can save a lot of money by making it permanent.
08-29-2015, 04:55 AM
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Why did Mazda sell the RX-8 with an incompetent cooling system?
Sorry for the late reply Steve. Thanks for all the info. I'm going to wire them to a switch and see if that helps. I'm also going to check on getting those FAL fans. If that doesn't work out, I'm going go fix a pusher fan on the front and see if that helps.
08-29-2015, 09:35 PM
#42
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I performed a little informal test for you, Nisaja. I wanted to see if running the fans at cruising speed really does create a restriction to air flow.
I warmed up my car and drove 6 miles from my house to the gas station and monitored my coolant temps while sustaining 55mph 90% of the way in 98F ambient heat in 5th gear at about 4000RPM. My average cruising coolant temp was 192F. On the way home, I did the same thing with my fan switch turned on. My average cruising coolant temp was 185F. The air conditioner was running on the same setting both ways. (I would normally cruise at that speed in 6th gear, but I wanted to create some heat for the test.)
It appears, at that speed, having the fans on actually helps. So, if your driving mainly consists of sitting in traffic and driving at speeds up to 55mph, it seems you can just run your fans on low and see some benefit (based on my previous testing and this new test) without worrying about any air flow restriction from the fans.
I may decide to run the test again with my data logger on and post some graphs. In any case, I think this mod is all you need to put your mind at ease. It is easy to do and is practically free, so there is no reason not to try it.
I warmed up my car and drove 6 miles from my house to the gas station and monitored my coolant temps while sustaining 55mph 90% of the way in 98F ambient heat in 5th gear at about 4000RPM. My average cruising coolant temp was 192F. On the way home, I did the same thing with my fan switch turned on. My average cruising coolant temp was 185F. The air conditioner was running on the same setting both ways. (I would normally cruise at that speed in 6th gear, but I wanted to create some heat for the test.)
It appears, at that speed, having the fans on actually helps. So, if your driving mainly consists of sitting in traffic and driving at speeds up to 55mph, it seems you can just run your fans on low and see some benefit (based on my previous testing and this new test) without worrying about any air flow restriction from the fans.
I may decide to run the test again with my data logger on and post some graphs. In any case, I think this mod is all you need to put your mind at ease. It is easy to do and is practically free, so there is no reason not to try it.
08-30-2015, 10:20 AM
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Why did Mazda sell the RX-8 with an incompetent cooling system?
Steve that is incredible! Good job! That kills that story for good. You have the fans on low I presume? Ever tried the fans on medium or high? That should keep the car even cooler! Yeah I'm mostly below 50mph. But my problem is not when moving, it's at idle. When I'm idling, the fans are already on high speed (because of the AC), and the temps get well above 220F. I'm going to try this mod though. At least it'll drop my temps a lot quicker when moving. Something is better than nothing. Thanks Steve! Great test. Very informative. I'm sure a lot will make use of this.
Has anyone tried changing just the fan motors? I heard these motors are made by Mitsubishi. Is that true? What if we grab a pair of high power fans from a different car and slap them on this? I'm talking about fans that pull a fair bit more amps than the stock fans.
Has anyone tried changing just the fan motors? I heard these motors are made by Mitsubishi. Is that true? What if we grab a pair of high power fans from a different car and slap them on this? I'm talking about fans that pull a fair bit more amps than the stock fans.
08-30-2015, 07:05 PM
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Something to consider is oil cooling, as that is responsible for a significant portion of overall cooling. Your low mileage suggests your oil coolers are likely in good shape. Any data on oil temperature?
08-30-2015, 08:57 PM
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Nah, I have had numerous oil cooler setups, NA and turbo, and it doesn't affect coolant temps at all really. On my current setup (Stock drivers side cooler and large BEHR secondary cooler from a Mercedes S class and no oil thermostats) I can't get my oil temps above 210F, but when pushing it hard under boost in this 100F weather I can hit 230F coolant temps.
08-31-2015, 02:38 PM
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Nah, I have had numerous oil cooler setups, NA and turbo, and it doesn't affect coolant temps at all really. On my current setup (Stock drivers side cooler and large BEHR secondary cooler from a Mercedes S class and no oil thermostats) I can't get my oil temps above 210F, but when pushing it hard under boost in this 100F weather I can hit 230F coolant temps.
Btw 9k, what are you idling temps with the FAL 420s? Did you notice a massive improvement when switching from the stock fans?
08-31-2015, 03:17 PM
#47
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Yes, the oil coolers are in pretty good shape. No bent fins. I have no way of monitoring my oil coolant temps. It's not on Torque
You hit 230F? Isn't that when the temp gauge starts to move? And you keep a straight face?
Btw 9k, what are you idling temps with the FAL 420s? Did you notice a massive improvement when switching from the stock fans?
You hit 230F? Isn't that when the temp gauge starts to move? And you keep a straight face?
Btw 9k, what are you idling temps with the FAL 420s? Did you notice a massive improvement when switching from the stock fans?
Yeah 230F is no biggie so long as you are not there for a very long time, it's only when I am on the throttle under full boost if I am driving hard. As soon as I left off it cool down to normal really quick. My engine also has heavy duty coolant seals from Pineapple Racing and I run Evans waterless coolant so temps are typically a tad bit higher (read up on Evans) than what I saw using normal coolant. The FAL fans make a huge difference in how fast the engine cools down at low speeds/idle. I am planning to run the FAL fan controller with a switch soon, I just have not gotten around to installing it. At idle in this 100F+ weather I typically sit at 195-205F or so.
Last edited by 9krpmrx8; 08-31-2015 at 03:26 PM.
08-31-2015, 03:37 PM
#48
So, while we're on the subject...
How was it ever determined that the stock coolant seals start to cook before the stock temp gauge moves? That seems like an extremely boneheaded design choice by Mazda. As in, I have a hard time imagining how it could possibly have been allowed to happen.
How was it ever determined that the stock coolant seals start to cook before the stock temp gauge moves? That seems like an extremely boneheaded design choice by Mazda. As in, I have a hard time imagining how it could possibly have been allowed to happen.
08-31-2015, 03:51 PM
#49
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Well, there is no science on it, just the general consensus from rebuilders and a few builders I have talked to think it has to do with the way the seals are installed. For example, my last Mazda Reman had a faulty coolant seal and my builder (Rob @ Pineapple Racing) said that a crap ton of RTV was was used where you don't use RTV. Yeah that's right, the Mazda reman plant puts RTV where the Mazda factory engine workshop manual does not call for RTV.
I have also see a few botched installs, there was one from Pettit recently that another rebuilder tore apart after the engine failed in short order and they cut the coolant seal (assuming during assembly) and instead of replacing it, the RTV's it together an assembled the engine.
Many people have gone to 240-250F on the track many times and never had a coolant seal fail so keep that in mind.
But Rotary Resurrection had one recently that had overheated so bad that the OMP lines melted on to the engine.
I have also see a few botched installs, there was one from Pettit recently that another rebuilder tore apart after the engine failed in short order and they cut the coolant seal (assuming during assembly) and instead of replacing it, the RTV's it together an assembled the engine.
Many people have gone to 240-250F on the track many times and never had a coolant seal fail so keep that in mind.
But Rotary Resurrection had one recently that had overheated so bad that the OMP lines melted on to the engine.