Full operating temp?

[NEALD]

I have been driving my 1999 Rav4 for a couple months now and notice my engine temp rarely goes above 185 F. Is this normal? It has been between 30-50 F outside for the duration I speak of, not sure if this is the reason why. What do others Ravs run at during these temps or warmer temps for that matter. I just want to catch a potential problem if I have one. Thanks.

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[hilander]

185F is fine

usu mine is at 190F but will go up to 205-210F in stop n go traffic

[NEALD]

That's about 15-20 degrees more than mine. What are the current temps in your area? I'm just worried if my temp sensor is not correct or if my engine is actually running too cool I maybe wasting fuel and not running optimally.

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[hilander]

I have read that 190F is the ideal operating temp for the 1997 rav which is what I have.

I see you have a 1999 so maybe someone else can weigh in here.

I live in the Piedmont area of NC so it doesnt get super cold. I also had my rav in WA State and it behaved pretty much the same as it is here.

[NEALD]

Thanks for your input. I am going to be flushing coolant come spring anyhow, I may as well replace the thermostat also as cheap insurance.

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[JuneBug]

Remember that any replacement thermostat needs to have the same temperature as the original part. If you try to run a cooler thermostat, the computer will sense the lower temp and continually try to raise it. Gas mileage will suffer, trust me.

[NEALD]

Yes thanks, this is the reason I want to make sure it is correct( correct state of tune and good fuel economy). It just seems that it is running a little too cool and maybe going into more fuel enrichment. Plus it couldn't hurt 2 flush the coolant that I have no idea how old it is , and replace the thermostat while I am at it. Besides my Rav runs really good and I want to keep it that way.

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[djb383]

A '99 is OBD-II so the system should enter "closed loop" due to the heated O2 sensor controlling air/fuel thus allowing for clean and lean running shortly after motor start-up and well before coolant temp reaches operating temp. Some heated O2s "light off" and start controlling air/fuel in as little as 8 seconds.

[NEALD]

Ok , so when running in closed loop it shouldn't even matter if the engine is a little cool since the ECU is calling for stoich using the o2 sensor, not the temp sensor . According to my torque app obd scanner my ECU does go into a closed loop operation, so my engine temps are definitely warm enough for that. Although today I was monitoring open/ closed loop operation after full warm up( over an hour of driving) the ECU entered open loop operation because of cool temperature . I think it may have been referring to 02 temp because coolant temp showed 185 f. It didn't affect running in anyway so I just took it as normal.

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[djb383]

There several driving conditions that momentarily cause "the loop" to re-enter "open", regardless of coolant temp. Both deceleration and acceleration will momentarily send the system from "closed" to "open". Again, once the O2 has reached it's operating temp (+/-650F) the system will enter "closed loop" but the system can also flip back and forth (open/closed), depending on driving conditions and programming in the ECU.