CJITTY

For any other LS600hL owners, have you experienced your hybrid not pushing warm air into the cabin when the gas engine shuts off, especially when creeping in traffic or parked? I don't notice a problem until it gets below 35 degrees or so, but after reading through this thread, it could be that my system is "air locked". The heat comes back when the gas engine is back on and usually driving above 30 mph or so. Just wondering if any of my fellow 600 owners have experienced this?

https://www.clublexus.com/forums/hyb...-cuts-out.html

caha14

Hi CJITTY,

Limited experience thus far, since it's my first cold season with the car, but I recently drove in temperatures below 30 and did not notice anything unusual. In fact, because this was all new to me, I went in expecting something different (precisely, if the engine "cooled down", etc.) but was pleasantly surprised.

I hope it's a simple fix for you.

NotADood

The 600hl has a belt driven water pump to circulate coolant. If you are at a stop light, and the engine shuts off, there will be no hot coolant going through your heater core to maintain heat. Lexus added electrical heaters to help aid when the engine is stopped, but the performance is nowhere near where to where the actual heater core can put out.

Additionally a coolant leak such as at the water pump could cause a loss of heat at low RPM's. If your coolant is low, try to top it off (when the engine is cold) and see if that helps.

wanderer99

Cjitty - I will test this out for you tomorrow morning and report back. Temps here at that time should be in the high 20's. Do you have your air set to Auto and temp at something like 72? I'm just asking because you might have this manually set to floor, 75 and medium fan (no Auto) or something. Just want to test this as close as possible to what you have your settings set to.

CJITTY

Coolant levels are full with no signs of leaks or smells and I have it set to auto mode at about 75 degrees. I've tried every possible combo..no auto..auto..air purifier on..rear on..rear off..floor..face..etc. only solution is to get back to 30 mph +. But now its warm here in GA again so I can't replicate the issue exactly the same. I have an appt tomorrow...CPO baby!!

I look forward to seeing what you find out..thanks for the responses

wanderer99

OK - I've tested this and my car still blows hot, even when the car has been in hybrid only mode for 6 mins. Outside temp was 28F, inside I set it to 75F on Auto mode. Car had been driven for about 45 mins so was definitely warmed up with coolant temp showing in the middle.

Car ran for about 6.5 mins before the engine started up again. Hybrid battery was still showing as full (1 bar down) but the engine coolant temp dropped a bar, so that's probably what made the engine start. At all times the air temp blowing down onto my feet was what I'd call very warm to hot. Hope that helps!

CJITTY

Thanks for your comments, that helps a lot. So I took my car in to my trusty dealership I normally use and they said my coolant was very low, yet the other dealer told me it was "overfilled'. So they flushed my entire system, added the coolant to the proper amount and now the car is blowing very hot air when set to higher temps. Then again, it is about 55 degrees here, so my true test will be when we get down in the mid to low 20s again here in Georgia..but for now, it's seems better

Thanks for your replies. I will be sure to report back on our next cold day (if we have one).

Vansibel

I drove my previous ls600 during winter (and pretty cold one in Quebec) and I never noticed any issue with warm air not getting pushed even when on electric only. It was my impression that if the climate control would not be able to deliver on electric mode only the gasoline engine would just start.

caha14

Good to hear. As cold season kicks in, I'll be sure to observe the behavior of the system more closely. Up here, we will definitely get many cold days.

While I haven't formally read this anywhere, my understanding had been consistent with Vansibel's, that the engine would come on were it to cool down excessively - not necessarily to warm up the cabin, but likely for emission purposes, so technically there should be no issue (when everything is operating normally).

Lastly, I don't know if you just changed the photo in your signature, or if I had missed it, but your car looks so damn sharp from that angle!

caha14

For what it's worth, since it was in the 20s this morning...

I had the heat at 68, as I usually do, and everything was operating normally. As soon as the engine reached operating temperature, it started to shut off, and the heat continued operating normally.

I then pulled into a parking lot and parked, but left everything on (and engine was off). Then, I cranked the heat up to 80, and it was nice and toasty. Within minutes, I noticed the coolant temperature gauge starting to move down very, very slightly. When the needle moved maybe a millimeter, the engine came back online.

Thus, the system seems to operate as many of us have been thinking. When the engine is off, there must be an electric pump to push coolant through the heater core. More generally, the ECU seems to be programmed to maintain the engine at operating temperature, and whatever it is that cools the engine down (i.e., running the heat for a while with the engine off, being shut off for too long, etc.) is not directly relevant: if the temperature drops, the engine should come back on.

Note, by the way, that the hybrid batteries were almost fully charged during my experiment (i.e., engine did not come on to charge the batteries, as confirmed by the energy monitor when the engine fired up).

CJITTY

Caha..great info!!! We had a 32 degree morning here in Atlanta the other day. Ever since I had the flush done, the heating of my 600 has been perfect. No more cold air rushing through in hybrid mode. It appears in my case that having proper coolant levels is everything. Interesting how the one dealership said I was "overfilled" and my normal trusty dealership said I was low. adjusted levels properly and now I'm ready for polar vortexes lol

Pamperme

Just curious: In the hybrid, is the heat available instantly upon a cold start? Or does it take time before the air is warm like in a conventional car?

CJITTY

Takes about 5 minutes of driving or so..around 10 min it's like South Africa in that modasucka

Pamperme

I never understood why cars can't have instant heat. It's not that hard to do. I've only known of one car that had heat instantly upon a cold start, and that was a rented Chevrolet Cruze.

CJITTY

This morning the temp was 10 degrees in Atlanta.. Yes HOTLanta ..today was the true test and I was very satisfied to know my issue is confirmed resolved. After about 5 minutes of driving the heat was blasting. Plenty of hybrid only mode during stop n go traffic and while at drive thru. Spent about 30 min in car. Issue resolved!!!