Intermittent Over Heating - Toyota GR86, 86, FR-S and Subaru BRZ Forum & Owners Community

Deep Six · 12-15-2014, 10:07 PM

A few weeks ago I noticed my water temp was running near 225 while cruising along on the interstate on a cool night. Temp fluctuated between 220 & 230 for about 15 minutes then suddenly dropped to the normal 190. No issues until this weekend when I noticed the temp was 225 as I pulled into the driveway on a fairly cold night. Additionally there was no warm air coming out the vents even though the knob was on max hot. Drove to work this morning in 45 degree weather and temps were again in the 220's and no hot air from the vents. However on the drive home, the temp was back at the usual 190 and the vents were providing hot air as expected.

I assume the thermostat is sticking and needs to be replaced but I have no idea how this affects the ventilation system ??

Dipstik-sportech · 12-15-2014, 10:12 PM

Check the coolant level, sounds like you have an air pocket in the system causing it to spike hot and stop the heater core from functioning.

JDKane527 · 12-15-2014, 11:07 PM

Your Robispec-Cooler is probably leaking coolant

Fastbrew · 12-16-2014, 12:47 AM

Have you replaced your coolant with something other than the factory blue supercoolant?
PS: It should be at the very bottom of the range in the reservoir just as it ships from the factory. Did you overfill?

Dipstik-sportech · 12-16-2014, 02:20 AM

Quote:

Originally Posted by JDKane527

Or your Robispec-Cooler is leaking coolant

Which would cause a low coolant level causing an air pocket........

Deep Six · 12-16-2014, 09:04 AM

No leaks, coolant in the reservoir is mid way between the marks. My logic is when the thermostat is closed obviously no coolant is sent to the radiator but I'm not sure if that would also cut off circulation to the heater core as well. When it did start working, it was like a switch was thrown and the temp plummeted back to normal. Seems like an air pocket stuck in the system would be a more persistent issue?

Dipstik-sportech · 12-16-2014, 09:22 AM

It all depends. Crack the bleed screw on the heater hose and see if it's straight coolant.

12-15-2014, 10:07 PM	#1
Deep Six Senior Member Join Date: May 2013 Drives: 2013 FRS / 2013 427 Vert Location: Orlando Posts: 611 Thanks: 212 Thanked 328 Times in 197 Posts Mentioned: 5 Post(s) Tagged: 0 Thread(s)	Intermittent Over Heating A few weeks ago I noticed my water temp was running near 225 while cruising along on the interstate on a cool night. Temp fluctuated between 220 & 230 for about 15 minutes then suddenly dropped to the normal 190. No issues until this weekend when I noticed the temp was 225 as I pulled into the driveway on a fairly cold night. Additionally there was no warm air coming out the vents even though the knob was on max hot. Drove to work this morning in 45 degree weather and temps were again in the 220's and no hot air from the vents. However on the drive home, the temp was back at the usual 190 and the vents were providing hot air as expected. I assume the thermostat is sticking and needs to be replaced but I have no idea how this affects the ventilation system ?? __________________ [SIGPIC][/SIGPIC] 2013 FR-S Asphalt BC Coils/Rev Works UEL header/HKS Front Pipe/Racing Brake BBK/Shorai LW Battery/ACT 6 Puck Clutch/FBM Radiator & Oil Pan/JR Oil Cooler/Jackson Racing High Boost C30/Rev Works Built Motor 2016 Audi TTS APR Tuned

12-15-2014, 10:12 PM	#2
Dipstik-sportech Senior Member Join Date: Oct 2012 Drives: 2013 BRZ satin white pearl sportech Location: Thunder Bay Ontario Canada Posts: 1,813 Thanks: 842 Thanked 911 Times in 576 Posts Mentioned: 43 Post(s) Tagged: 0 Thread(s)	Check the coolant level, sounds like you have an air pocket in the system causing it to spike hot and stop the heater core from functioning. __________________ 2013 SWP BRZ sportech. 11.11sec@129.01mph, 511whp on e70. FullBlown base kit, FullBlown built 9.5:1 engine, GTX3076R GEN2 turbo, 1700cc Bosch injectors, FullBlown flex fuel kit, FullBlown radiator and oil cooler, FullBlown custom 3" dual exit exhaust, act xtreme clutch, whiteline diff and subframe inserts, BC Racing coilovers, hotchkiss 18mm rear sway, is300 3.73 differential ... Never finished

12-15-2014, 11:07 PM	#3
JDKane527 Senior Member Join Date: Jan 2013 Drives: Asphalt Scion FR-S Location: Los Angeles, CA Posts: 499 Thanks: 274 Thanked 215 Times in 136 Posts Mentioned: 10 Post(s) Tagged: 1 Thread(s)	Your Robispec-Cooler is probably leaking coolant __________________ Asphalt Build Last edited by JDKane527; 12-16-2014 at 03:18 AM. Reason: Reworded

12-16-2014, 09:04 AM	#6
Deep Six Senior Member Join Date: May 2013 Drives: 2013 FRS / 2013 427 Vert Location: Orlando Posts: 611 Thanks: 212 Thanked 328 Times in 197 Posts Mentioned: 5 Post(s) Tagged: 0 Thread(s)	No leaks, coolant in the reservoir is mid way between the marks. My logic is when the thermostat is closed obviously no coolant is sent to the radiator but I'm not sure if that would also cut off circulation to the heater core as well. When it did start working, it was like a switch was thrown and the temp plummeted back to normal. Seems like an air pocket stuck in the system would be a more persistent issue? __________________ [SIGPIC][/SIGPIC] 2013 FR-S Asphalt BC Coils/Rev Works UEL header/HKS Front Pipe/Racing Brake BBK/Shorai LW Battery/ACT 6 Puck Clutch/FBM Radiator & Oil Pan/JR Oil Cooler/Jackson Racing High Boost C30/Rev Works Built Motor 2016 Audi TTS APR Tuned

12-16-2014, 09:22 AM	#7
Dipstik-sportech Senior Member Join Date: Oct 2012 Drives: 2013 BRZ satin white pearl sportech Location: Thunder Bay Ontario Canada Posts: 1,813 Thanks: 842 Thanked 911 Times in 576 Posts Mentioned: 43 Post(s) Tagged: 0 Thread(s)	It all depends. Crack the bleed screw on the heater hose and see if it's straight coolant. __________________ 2013 SWP BRZ sportech. 11.11sec@129.01mph, 511whp on e70. FullBlown base kit, FullBlown built 9.5:1 engine, GTX3076R GEN2 turbo, 1700cc Bosch injectors, FullBlown flex fuel kit, FullBlown radiator and oil cooler, FullBlown custom 3" dual exit exhaust, act xtreme clutch, whiteline diff and subframe inserts, BC Racing coilovers, hotchkiss 18mm rear sway, is300 3.73 differential ... Never finished

12-16-2014, 12:47 AM	#4
Fastbrew Senior Member Join Date: Apr 2014 Drives: 2014 Pearl White BRZ Location: USA Posts: 764 Thanks: 123 Thanked 461 Times in 233 Posts Mentioned: 7 Post(s) Tagged: 0 Thread(s)	Have you replaced your coolant with something other than the factory blue supercoolant? PS: It should be at the very bottom of the range in the reservoir just as it ships from the factory. Did you overfill?

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