opinion on refrigerent temp/IAT temp read out
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From: Diamond Bar, CA
W206 PHEV AMG
opinion on refrigerent temp/IAT temp read out
been checking the refrigerent temp (some say it's IAT) from the a/c diagnostic mode under number 08. The outside temp at night for the past couple days has been well under 60.
The running temp when the car is on the move the the temp showing up on the a/c is well below 75 however here is where my confusion starts. When the car is stopped the temperature indicated quickly raises up to 80-90 degrees on short stops at the stop light which seems normal from before, but here is where it goes
for me. during those long stops when i'm parked or when I'm waiting in the drive-thru for a long period of time I'm seeing the temp topping 110-115.
this is after the heat exchanger has been installed, but the coolant wasn't flushed. maybe I need to flush the coolant? or something is wrong with the temperature sensor (but where is this sensor located)
btw, just for reference I've asked Mike/Temjin to check his (he has the heat exchanger and coolant pump, but no other power mods). his starting temp is around 75 and idling for 5min bring him up to around 80-85.
edit: forgot to mention the car drives fine with no lost of power.
The running temp when the car is on the move the the temp showing up on the a/c is well below 75 however here is where my confusion starts. When the car is stopped the temperature indicated quickly raises up to 80-90 degrees on short stops at the stop light which seems normal from before, but here is where it goes
for me. during those long stops when i'm parked or when I'm waiting in the drive-thru for a long period of time I'm seeing the temp topping 110-115. this is after the heat exchanger has been installed, but the coolant wasn't flushed. maybe I need to flush the coolant? or something is wrong with the temperature sensor (but where is this sensor located)
btw, just for reference I've asked Mike/Temjin to check his (he has the heat exchanger and coolant pump, but no other power mods). his starting temp is around 75 and idling for 5min bring him up to around 80-85.
edit: forgot to mention the car drives fine with no lost of power.
Last edited by FrankW; Feb 12, 2009 at 07:19 PM.
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From: Llandudno, Cape Town, South Africa
late 2009 CLK 350 Coupe Elegance, '65 Jaguar S Type wires
Frank,
Got your message. I understand refrigeration & Aircons & a bit about thermodynamics. I don't know the C32 particularly well or your mods. That said - can we try and establish exactly what we are measuring here. Is it Inlet Air Temp or refrigerant temp & where is the sensor in the circuit - I will do some scratching but will you please try & establish this. Does your coolant temperature creep up in unison with IAT or Refrigerant temperature? (maybe not as much but do you see a rise) Do you have a touch thermometer and are you able to take a temperature at the Aircon condenser unit at the radiator? May be difficult to get a representative reading with radiator influence??? An evapourator temp would also be useful.
Is the (radiator) electric fan operational & does it kick in during these idle periods? (It should not 115F is only 46C). I doubt that changing the coolant will make any difference. Are you however sure that there is no air in the system & that it has been properly bled?
Is your aircon operating normally?
I presume your worry here is IF this is a raise in IAT it will compromise power output? Let's understand what you are really chasing here or is it just the difference between your & Mike's cars.
I really think that this is some minor heat soak while stationary.
Let's go back to basics see pics below:
Can we establish what we are measuring and at what point we are measuring it.
Got your message. I understand refrigeration & Aircons & a bit about thermodynamics. I don't know the C32 particularly well or your mods. That said - can we try and establish exactly what we are measuring here. Is it Inlet Air Temp or refrigerant temp & where is the sensor in the circuit - I will do some scratching but will you please try & establish this. Does your coolant temperature creep up in unison with IAT or Refrigerant temperature? (maybe not as much but do you see a rise) Do you have a touch thermometer and are you able to take a temperature at the Aircon condenser unit at the radiator? May be difficult to get a representative reading with radiator influence??? An evapourator temp would also be useful.
Is the (radiator) electric fan operational & does it kick in during these idle periods? (It should not 115F is only 46C). I doubt that changing the coolant will make any difference. Are you however sure that there is no air in the system & that it has been properly bled?
Is your aircon operating normally?
I presume your worry here is IF this is a raise in IAT it will compromise power output? Let's understand what you are really chasing here or is it just the difference between your & Mike's cars.
I really think that this is some minor heat soak while stationary.
Let's go back to basics see pics below:
Can we establish what we are measuring and at what point we are measuring it.
Last edited by Glyn M Ruck; Feb 13, 2009 at 05:33 AM.
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From: Corona, CA
03 g35 coupe...........02 c32 Sold
actually just to clarify, i have the code 3 heat exchange, code 3 intake and code3 pulley and tune and a johnson cm30 pump.
I think you just need to flush out all the air bubbles. There was a lot of air after i installed mine. You should just PM splinter on how to flush out the air bubbles.
I remember when open the resevoir cap and squeeze the return line, i was able to get out a lot of the air bubbles. I had to run the intercooler pump on the acc circuit while the car was idle to get out the rest.
I think you just need to flush out all the air bubbles. There was a lot of air after i installed mine. You should just PM splinter on how to flush out the air bubbles.
I remember when open the resevoir cap and squeeze the return line, i was able to get out a lot of the air bubbles. I had to run the intercooler pump on the acc circuit while the car was idle to get out the rest.
Last edited by TemjinX2; Feb 19, 2009 at 01:15 AM.
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GMC - Miata - Trek - P-Car
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#08 is almost certainly not refrigerant temperature.
My observations closely parallel yours, in that the readings quickly escalate when the car is stationary. Your thread got me to thinking – seldom a good thing for the membership at large.
Did some data logging comparing the #08 readout and post-intercooler IATs. At times, they’re almost identical. But not always. They varied by as much as 40 degrees, depending upon operating conditions, during the brief test. Under light-load highway operation, the IAT’s tend to hover ~20 degrees above OAT with its LET heat exchanger. At WOT, IATs will increase while the HVAC reading remains relatively stable. When there is no airflow through the engine compartment, the increasing #08 figures rapidly outpace those from the IAT sensor.
Next time we catch up, we’ll do some data logging to see if yours is working similarly and verify that your intercooler circuit is working as it should.
Edit: any chance you’re joining us mañana for the canyon GTG?
#08 is almost certainly not refrigerant temperature.
My observations closely parallel yours, in that the readings quickly escalate when the car is stationary. Your thread got me to thinking – seldom a good thing for the membership at large.
Did some data logging comparing the #08 readout and post-intercooler IATs. At times, they’re almost identical. But not always. They varied by as much as 40 degrees, depending upon operating conditions, during the brief test. Under light-load highway operation, the IAT’s tend to hover ~20 degrees above OAT with its LET heat exchanger. At WOT, IATs will increase while the HVAC reading remains relatively stable. When there is no airflow through the engine compartment, the increasing #08 figures rapidly outpace those from the IAT sensor.
Next time we catch up, we’ll do some data logging to see if yours is working similarly and verify that your intercooler circuit is working as it should.
Edit: any chance you’re joining us mañana for the canyon GTG?
Last edited by splinter; Feb 20, 2009 at 10:12 PM.
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Joined: Apr 2002
Posts: 22,058
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From: Diamond Bar, CA
W206 PHEV AMG
https://mbworld.org/forums/c32-amg-c...en-c-menu.html
#08 is almost certainly not refrigerant temperature.
My observations closely parallel yours, in that the readings quickly escalate when the car is stationary. Your thread got me to thinking – seldom a good thing for the membership at large.
Did some data logging comparing the #08 readout and post-intercooler IATs. At times, they’re almost identical. But not always. They varied by as much as 40 degrees, depending upon operating conditions, during the brief test. Under light-load highway operation, the IAT’s tend to hover ~20 degrees above OAT with its LET heat exchanger. At WOT, IATs will increase while the HVAC reading remains relatively stable. When there is no airflow through the engine compartment, the increasing #08 figures rapidly outpace those from the IAT sensor.
Next time we catch up, we’ll do some data logging to see if yours is working similarly and verify that your intercooler circuit is working as it should.
Edit: any chance you’re joining us mañana for the canyon GTG?
#08 is almost certainly not refrigerant temperature.
My observations closely parallel yours, in that the readings quickly escalate when the car is stationary. Your thread got me to thinking – seldom a good thing for the membership at large.
Did some data logging comparing the #08 readout and post-intercooler IATs. At times, they’re almost identical. But not always. They varied by as much as 40 degrees, depending upon operating conditions, during the brief test. Under light-load highway operation, the IAT’s tend to hover ~20 degrees above OAT with its LET heat exchanger. At WOT, IATs will increase while the HVAC reading remains relatively stable. When there is no airflow through the engine compartment, the increasing #08 figures rapidly outpace those from the IAT sensor.
Next time we catch up, we’ll do some data logging to see if yours is working similarly and verify that your intercooler circuit is working as it should.
Edit: any chance you’re joining us mañana for the canyon GTG?
good data logging John. this could be with the LET HE since Mike has the code3 and the temp does not raise as fast.
and yes, i'll be there tomorrow.
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From: Llandudno, Cape Town, South Africa
late 2009 CLK 350 Coupe Elegance, '65 Jaguar S Type wires
https://mbworld.org/forums/c32-amg-c...en-c-menu.html
#08 is almost certainly not refrigerant temperature.
My observations closely parallel yours, in that the readings quickly escalate when the car is stationary. Your thread got me to thinking – seldom a good thing for the membership at large.
Did some data logging comparing the #08 readout and post-intercooler IATs. At times, they’re almost identical. But not always. They varied by as much as 40 degrees, depending upon operating conditions, during the brief test. Under light-load highway operation, the IAT’s tend to hover ~20 degrees above OAT with its LET heat exchanger. At WOT, IATs will increase while the HVAC reading remains relatively stable. When there is no airflow through the engine compartment, the increasing #08 figures rapidly outpace those from the IAT sensor.
Next time we catch up, we’ll do some data logging to see if yours is working similarly and verify that your intercooler circuit is working as it should.
Edit: any chance you’re joining us mañana for the canyon GTG?
#08 is almost certainly not refrigerant temperature.
My observations closely parallel yours, in that the readings quickly escalate when the car is stationary. Your thread got me to thinking – seldom a good thing for the membership at large.
Did some data logging comparing the #08 readout and post-intercooler IATs. At times, they’re almost identical. But not always. They varied by as much as 40 degrees, depending upon operating conditions, during the brief test. Under light-load highway operation, the IAT’s tend to hover ~20 degrees above OAT with its LET heat exchanger. At WOT, IATs will increase while the HVAC reading remains relatively stable. When there is no airflow through the engine compartment, the increasing #08 figures rapidly outpace those from the IAT sensor.
Next time we catch up, we’ll do some data logging to see if yours is working similarly and verify that your intercooler circuit is working as it should.
Edit: any chance you’re joining us mañana for the canyon GTG?
Thread Starter
MBworld Guru
Joined: Apr 2002
Posts: 22,058
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From: Diamond Bar, CA
W206 PHEV AMG
from different reads through the forum some say it's IAT, but from c32used's one stop search thread another listed as refrigerant. I guess John's assessment clear my doubt on the refrigerant part.
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From: Llandudno, Cape Town, South Africa
late 2009 CLK 350 Coupe Elegance, '65 Jaguar S Type wires
