mmarzluf

Just bought my IS250 a few weeks ago. 75k miles. Everything is mint, but the heater only puts out hot air at 2000 rpms or higher. Idle gives Luke warm air, not even close to hot. I topped off the coolant overflow and it has taken a small amount, but nothing to suggest being low on coolant. Wondering if maybe it had been flushed improperly before and has some air in the system or maybe the thermostat isn't working properly.

Anyone have any ideas. ? The rest of the air system works perfectly.

quick123

iTrader: (2)

Topping off the coolant overflow will not do anything but cause it to eventually purge out...if there are some air pockets in the coolant system, you need to add coolant at the radiator cap itself until it doesn't take any more (and watch for air bubbles/burping)...

That might be whats going on, but I really don't know...you may have stumped me

mmarzluf

Thanks Quick.

That's exactly what the issue was. If I had to guess, it was about 1 Qt low on coolant. Just enough to cause an air pocket in the system preventing it from flowing correctly. After topping off at the cap, and squeezing the upper and lower hoses, It appears to be well burped and heating well.

Believe it or not, I performed this yesterday and just read your reply this afternoon. I guess great minds think alike.

Funny, even as sophisticated as these new cars get, it's the simple, age old problems that can make you scratch your head for a while. LOL.