My previous cars have all reached their normal operating temperature (coolant temperature guage needle in the middle) after about 1/2 mile. My new IS250 is very slow coming up to normal operating temperatures (10 miles before the needle reaches the middle/normal position). Yeah, I know, probably the thermostat stuck open. However, I'm reluctant to have the dealer replace the thermostat as I don't think it's a trivial replacement. Anybody know if you have to remove timing belts/water pump as you have to do with most other cars? Could it be anything else?

 

Its normal. My IS takes longer to warm up then my previous cars also. The thermostat is not stuck open, its just a characteristic of the car. So don't waste your time going to the dealer. If your theromostat was really open the engine will NEVER warm up with the needle never being in the "middle" position. This happend to my Acura Integra.

 

I think it is normal too. I usually wait for the initial hum/warmup to complete.
after like 20 seconds or so.

If on a very cold day, then I wait until the needle approaches the "C" before moving on...couple minutes or so.

But in general it takes more time than my previous vehicles.

 

Yup...I have noticed this too while driving to work each morning. It's normal.

 

Know what is different on top of that. When the engine is cold you notice the white exhaust fumes. After driving 10 miles it still has that white fumes coming out. My other cars stop doing that after about 2-3 miles.

 

Hmmmm.......... it may be typical of the IS250 but it's definitely not "normal". The thermostat should be closed until the water/block heats up (this is for max fuel economy/minimum emissions) and then open up to permit the optimum cooling of the engine. Sounds like someone at Lexus spec'd the wrong thermostat for the IS250 and no-one has noticed yet(?)

 

I have the same issue. I've had the car for about 6 months and this is it's first winter. To me, the car takes a long time to warm up. Dealer ran diagnostic -- no faults -- said that everything was fine. Never had a car that took so long to warm up... other than that, the car has been great.

 

yea mine takes forever to warm up.. anytime its cold and i start it.. its probably 3 times as loud.. then when i start it up and its warm

 

lol. How do you know its open when cold?

Its normal. Both IS250/350 do this. It just takes a bit longer to warm up. No big deal. Maybe the IS has a large volume of coolant then the previous car that we owned.

 

At least the heated seats start working a 1/4 mile before the blower starts to send out any air when set to "auto." :4|