Overheating. No fan?
07-24-2016, 05:00 AM
#26
Yes the car overheats when I rev the car. Lets say there is someone really slow in fron of me and i pass them and rev it it goes up even sometimes at 60 mph but it goes up like 4 lines but it never reaches the red light. But it overheats usually when ac is on the. I turn it off then goes back to mid line. How would i know if the relays are bad? And what relays should i check? Colling1 & cooling2? I want to fix it but im really shor on money and plus usually no ones knows how to work in this cars.
Be careful. The stock temperature gauge doesn't move from the middle until the temperature is 230 F. 4 lines up on the gauge is about 237-238 F. 243 F is the limit of what Mazda considers safe for the engine. Above that you are risking engine damage from even a single overheating event. The gauge maxes out at about 250 F. We have seen multiple people, who have overheated and maxed out the gauge, report engine problems that result in a rebuild or replacement of the engine. Operating at 230F as you are, while not immediately catastrophic, will degrade your coolant seals and cause a coolant leak from the cooling jacket into the combustion chamber, if you do it for long enough. This will manifest itself as dropping coolant levels, difficulty starting and white smoke from the exhaust. If you absolutely must drive the car in the current condition, keep the AC off until you get your issue figured out.
As uncomfortable as that will be, better than an engine rebuild.
Last edited by Jastreb; 07-24-2016 at 05:03 AM.
07-26-2016, 03:24 AM
#28
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Even moderate acceleration on a heat soaked engine can increase the coolant temperature by 5 degrees or more.
Be careful. The stock temperature gauge doesn't move from the middle until the temperature is 230 F. 4 lines up on the gauge is about 237-238 F. 243 F is the limit of what Mazda considers safe for the engine. Above that you are risking engine damage from even a single overheating event. The gauge maxes out at about 250 F. We have seen multiple people, who have overheated and maxed out the gauge, report engine problems that result in a rebuild or replacement of the engine. Operating at 230F as you are, while not immediately catastrophic, will degrade your coolant seals and cause a coolant leak from the cooling jacket into the combustion chamber, if you do it for long enough. This will manifest itself as dropping coolant levels, difficulty starting and white smoke from the exhaust. If you absolutely must drive the car in the current condition, keep the AC off until you get your issue figured out. As uncomfortable as that will be, better than an engine rebuild.
Be careful. The stock temperature gauge doesn't move from the middle until the temperature is 230 F. 4 lines up on the gauge is about 237-238 F. 243 F is the limit of what Mazda considers safe for the engine. Above that you are risking engine damage from even a single overheating event. The gauge maxes out at about 250 F. We have seen multiple people, who have overheated and maxed out the gauge, report engine problems that result in a rebuild or replacement of the engine. Operating at 230F as you are, while not immediately catastrophic, will degrade your coolant seals and cause a coolant leak from the cooling jacket into the combustion chamber, if you do it for long enough. This will manifest itself as dropping coolant levels, difficulty starting and white smoke from the exhaust. If you absolutely must drive the car in the current condition, keep the AC off until you get your issue figured out.
As uncomfortable as that will be, better than an engine rebuild.
07-26-2016, 07:45 AM
#29
Power steering can be due to coolant dripping on the electric power steering connector. Which could easily be because the coolant overflow bottle is cracked or the pressure cap is not sealing; or someone messed with the overflow bottle and cracked the nipple on the radiator it attaches to. Any of those things will both put coolant on your EPS connector and cause the overheating you're seeing. Inspect the bottle, especially the neck for cracks and traces of coolant leaking.
08-03-2016, 02:21 PM
#31
Cooling Fan Relays?
I have a similar problem. 2005 Rx8, 150K miles but engine rebuilt at 125k. Noticed running hot (close to 230 when stuck in bumper to bumper in Miami). I replaced stock radiator with aluminum but kept the stock fans. Used Mazda premix coolant. Still runs hot. Noticed the fans don't seem to stay on after shutting engine down like they used to. I figured either one of the fan motors or relay were bad. So I applied power to each motor and they both ran fine. So Im thinking one of the relays are bad. I ordered the cooling fan relay number 3, which has 5 terminals. I should get it in a day thinking its only $10 and is the original. Any other thoughts?
Summary: Fans are good, radiator is aluminum. New Mazda coolant. Still runs hot. Think it is a fan issue not coming on at correct time.
Additional Information: I followed the recommended test procedure of jumping the relay connection for Cooling Fan #!, but that did not trigger the fan. I then looked at the wiring diagram and noticed that Fan #1 gets its ground only when the PCM applies energizes Fan Relay #2, which is a grounding relay. If I jump both relay 1 and also relay 2, then Fan #1 goes on. Also, let the car run till so it warms up. I turned on the A/C and the fan turned on. Switched A/C off and the fan turned off. It did turn on once the car got hot, even with the A/C off. It seems like only Fan #2 runs. Again, when direct power is applied to the Fans, the both work, so not a fan issue. Still thinking Fan Relay #3.
Summary: Fans are good, radiator is aluminum. New Mazda coolant. Still runs hot. Think it is a fan issue not coming on at correct time.
Additional Information: I followed the recommended test procedure of jumping the relay connection for Cooling Fan #!, but that did not trigger the fan. I then looked at the wiring diagram and noticed that Fan #1 gets its ground only when the PCM applies energizes Fan Relay #2, which is a grounding relay. If I jump both relay 1 and also relay 2, then Fan #1 goes on. Also, let the car run till so it warms up. I turned on the A/C and the fan turned on. Switched A/C off and the fan turned off. It did turn on once the car got hot, even with the A/C off. It seems like only Fan #2 runs. Again, when direct power is applied to the Fans, the both work, so not a fan issue. Still thinking Fan Relay #3.
Last edited by rcatala59; 08-03-2016 at 03:15 PM.
08-03-2016, 10:54 PM
#32
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Yes turning on the AC in hot weather will usually force both fans to go on high. You can test if they're coming on at the desired coolant temps. They should both go on low speed at 206F and both on high speed at 213.8F.
08-08-2016, 07:41 PM
#33
Finally solved the problem of car running hot.
Recap: Engine rebuilt about a year ago. Replaced stock radiator with an aluminum radiation. Kept factory fans, which both tested fine. Use FL-22 coolant. Car was still running hot, so I tested the relays. Cooling Fan relay 3 was stuck open. Replaced it. Ran a little cooler, but still around 220. Expected much cooler with the aluminum radiator.
It finally occurred to me to ask the rebuilder if he replaced the thermostat. He said he didn't that the original was good. So I bought an OEM thermostat (190). Was kind of a pita to install, but did it. What a difference. I was in stuck in stop and go traffic in Miami yesterday, with ambient temperatures of about 95. Car never went about 205.
We tend to think that since the radiator hose feels full if you squeeze it, and fans come on and off, then the therm must be ok. But what if it doesn't open all the way? That was my problem. OEM thermostat only $35. A little more that NAPA, but hey, it is an OEM part. Good luck!
Recap: Engine rebuilt about a year ago. Replaced stock radiator with an aluminum radiation. Kept factory fans, which both tested fine. Use FL-22 coolant. Car was still running hot, so I tested the relays. Cooling Fan relay 3 was stuck open. Replaced it. Ran a little cooler, but still around 220. Expected much cooler with the aluminum radiator.
It finally occurred to me to ask the rebuilder if he replaced the thermostat. He said he didn't that the original was good. So I bought an OEM thermostat (190). Was kind of a pita to install, but did it. What a difference. I was in stuck in stop and go traffic in Miami yesterday, with ambient temperatures of about 95. Car never went about 205.
We tend to think that since the radiator hose feels full if you squeeze it, and fans come on and off, then the therm must be ok. But what if it doesn't open all the way? That was my problem. OEM thermostat only $35. A little more that NAPA, but hey, it is an OEM part. Good luck!
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10-10-2016, 06:07 PM
#36
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FYI - For what it is worth, if your RX8 has high heat at idle (214+ degrees F), and the power steering has failed at some time due to coolant overflow (before you extended the overflow hose), be certain to check to see if the right hand (passenger side) fan turns on to low speed at about 206.6 degrees F. The connector for the fan motor is fairly close to the overflow hose, and as many have found out the coolant can corrode terminals and break the electrical connection.
I just went through the same overheating issues discussed in this thread. I replaced the radiator (broken nipple to overflow tank) and the thermostat (replaced a Stant thermostat that was likely bad from day 1) with an OEM thermostat. I also replaced the air conditioning condenser (didn't even try to straighten those fins). The temps were then fine at speed, but went up to 216 F at idle, at which point I could hear a radiator fan turn on to the high speed setting. A few days later my power steering went out, which I reasoned was likely due to spilling coolant into the power steering connectors while I was refilling the radiator. As I was cleaning the connectors, I noticed the right-hand fan connector was close by, and the light came on! I cleaned the fan motor connector, and the high heat at idle problem went away. Duh! I never suspected that the fan was not turning, since I could hear the left-hand fan go on at high speed. I now suspect that the fan has not been working since the first time the power steering went out a few years ago.
I also just installed the RX8 Performance cooling fan control kit to further reduce idle temperature. Cooling Fan Control Kit by RX-8 Performance | RX8Performance.com
Since I was only concerned about idle temps, and was not certain that the high speed fan setting was necessary, I replaced only the #1 fan relay. The fans now turn on at about 192 F, but on low speed rather than high speed. I put the other kit relay in bubble wrap and let it sit on top of the relays. If I decide I need additional cooling at some time, I can simply plug it into the #2 fan relay.
[2004 Grand Touring, ACT Lightweight Flywheel, Centerforce DFX Clutch, Greddy Catback, Corksport Front Upper Strut Brace, Racing Beat Complete Gauge Panel Kit, TSW 18x8 Trackstar Rims, Sohn’s adapter, oil catch can, reinforced clutch, Mazmart Oil Pressure Regulator, RX8 Performance cooling fan control kit, aluminum radiator, intake and oil cooler screens, Galaxy Pad 3 install (replaced factory navigation), Bluetooth OBDII, Mazda 02-08 GROM USB Android iPod iPhone Bluetooth AUX car kit]
I just went through the same overheating issues discussed in this thread. I replaced the radiator (broken nipple to overflow tank) and the thermostat (replaced a Stant thermostat that was likely bad from day 1) with an OEM thermostat. I also replaced the air conditioning condenser (didn't even try to straighten those fins). The temps were then fine at speed, but went up to 216 F at idle, at which point I could hear a radiator fan turn on to the high speed setting. A few days later my power steering went out, which I reasoned was likely due to spilling coolant into the power steering connectors while I was refilling the radiator. As I was cleaning the connectors, I noticed the right-hand fan connector was close by, and the light came on! I cleaned the fan motor connector, and the high heat at idle problem went away. Duh! I never suspected that the fan was not turning, since I could hear the left-hand fan go on at high speed. I now suspect that the fan has not been working since the first time the power steering went out a few years ago.
I also just installed the RX8 Performance cooling fan control kit to further reduce idle temperature. Cooling Fan Control Kit by RX-8 Performance | RX8Performance.com
Since I was only concerned about idle temps, and was not certain that the high speed fan setting was necessary, I replaced only the #1 fan relay. The fans now turn on at about 192 F, but on low speed rather than high speed. I put the other kit relay in bubble wrap and let it sit on top of the relays. If I decide I need additional cooling at some time, I can simply plug it into the #2 fan relay.
[2004 Grand Touring, ACT Lightweight Flywheel, Centerforce DFX Clutch, Greddy Catback, Corksport Front Upper Strut Brace, Racing Beat Complete Gauge Panel Kit, TSW 18x8 Trackstar Rims, Sohn’s adapter, oil catch can, reinforced clutch, Mazmart Oil Pressure Regulator, RX8 Performance cooling fan control kit, aluminum radiator, intake and oil cooler screens, Galaxy Pad 3 install (replaced factory navigation), Bluetooth OBDII, Mazda 02-08 GROM USB Android iPod iPhone Bluetooth AUX car kit]
10-10-2016, 09:40 PM
#37
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nice catch
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