ThumperPup

Issue with no heat today i had the temp turned up to high and had it set on auto remote started the vehicle 15 minutes no heat was coming out let it run another 15 minutes no heat
then i started to drive down the road after i started driving heat started coming out of the vents i let my foot off the gas and slowed down and it started to blow cold again
what should i look at ?
07 ES350

jagtoes

What was your water temp.

ThumperPup

what do you mean you mean the engine temp gauge? that was reading normal it was at temp the temp gauge was normal reading where it always is for operating temp once its warmed up

ESh

Low on coolant or bad water pump.

jagtoes

Considering the car is running at normal temps I would be looking at the heater matrix as a potential problem. The heat valve may be bad or the dash electronics may be the problem. I believe the Lexus diagnostic tool can check for heater/AC function.

ThumperPup

i checked codes yesterday and nothing was coming up
i will check codes again today and see if anything comes up for any error codes.

ThumperPup

coolant level looked good

water pump was replaced with a Factory OEM water pump 4 years ago
luckily i still have the service contract doesn't expire for another 2700 more miles
so if it needs to be replaced i just pay 100 and contract pays the rest.

if it was the Thermostate would i have codes saying that its stuck open or closed ? would there be a high or low current code to the thermostat sensor if it was stuck open

also some other info 2 years ago the Radiator was replaced the thermostat was replaced also at the same time from what i remember and it was proper TOyota Lexus Long life coolant that was used because it was at the dealership these where replaced so i don't think that there could be air in the system
i never see any jumps in engine temp or overheating or anyting

2013FSport

iTrader: (2)

How did you verify coolant level?
Looking at the reservoir level may not tell the whole story.

Also keep in mind the dash gauges tend to be normalized and remain parked in one location even tho the engine temp is swinging +/-25°F around 180°. That said it should still blow warm even if block is at 175°F.

What are the ambient temps?

ThumperPup

This morning I plugged in my code reader and scanner and let it warm up to temp idling for 10 minutes it warmed up at first it was nice and warm when I got into the car after letting it run
then I started to drive down the road it got warmer when I stopped at the first stop sign I waited for a moment and it started to cool down the air started to get cool just air no heat blowing just seemed like the fan was on the Scanner was reading that the ETC .oF temp was 180 I then started to drive put my foot on the gas and heat started coming out really hot heat
I then got to a red light I checked the scanner for temp reading it was showing temp was reading ETC Temp was 185 and a few moments after stopping at the red light it starts to blow fan no heat just cool fan.
I got onto the highway and the temp stayed steady for like 60 miles of driving it would move between 185 and 187 ETC Temp after and heat was nice and hot
I got off the highway and will I was waiting to turn the ETC temp went up to 190 and fan started blowing cold again

So this is what has been happening
the outside temp when I first started out this morning was 36 in the city
the temp when I got off the highway had dropped to 23 degrees these where the outside natural temps during these following steps above

jagtoes

1st there is no special code for the HVAC system at the OBDII connector. Usuall there are other methods that the dealer can access from there with their special equipment. Normal water temp. should be at 195* +/- 10* so even though your readings are at the low end you still have 180*+ of heat in the system. So this brings me back to either the blend valve or the heater valve or the electronics in the dash that control the heater unit. Are you also running in the AUTO mode and have you tried running the auto off. How high are you setting your temps.

ThumperPup

this is no matter what mode its in auto or non auto mode

ThumperPup

Took it to the dealership today
They said that it was because the antifreeze was low even thought it didn't look low they said it was low.
the cooling system was Bled and then Filled up then they let it idle for a while and was testing the heat was coming out at 160 Degree on idle they temped it at from the vents.
63 dollars is what they charged so not bad for the Lexus dealership on this.

however, i notice it isn't cooking down when it's on high it's coming out nice and hot but it does seem to cool down a bit more than you would think it should if you turn it down below 85 like if I set it at 83 or 84 it starts to chill out a bit
so as long as it stays working and I don't have any problems I'm happy.

i did check the ETC temp and its reading around 187 to 199 today it did go above 200 for a moment its currently 33 degree outside

ESh

told ya, low on coolant.

jagtoes

Once again we ASSUMED you were smart enough to check your coolant level. It would have been the 1st thing to check. Good luck.

12jimmyjam

He did say it didn’t look low...