Heater blowing cold
11-07-12, 09:49 AM
#16
Lexus Test Driver
It's possible in case OP have system with radiator cap. I don't. I have an expansion (unpressurised!) tank system on my 2001 and there's no radiator caps employed...
11-10-16, 09:43 PM
#18
Have some heat when set at max. Not much at lower settings. I've just had the coolant drained and replaced. Tech says it looked fine. New radiator cap. Pressure tested system and it's fine. Heat valve (bulkhead placement) arm moves to correct max hot and max cold settings.AC works perfectly (fans blow at low/medium/high settings). I suppose it could be a clogged heater core or defective temp sensor. Suggests much appreciated!
12-18-16, 02:48 PM
#19
Driver School Candidate
Have some heat when set at max. Not much at lower settings. I've just had the coolant drained and replaced. Tech says it looked fine. New radiator cap. Pressure tested system and it's fine. Heat valve (bulkhead placement) arm moves to correct max hot and max cold settings.AC works perfectly (fans blow at low/medium/high settings). I suppose it could be a clogged heater core or defective temp sensor. Suggests much appreciated!
12-19-16, 06:12 AM
#21
Pole Position
The thermostat may be stuck open or the rubber seal around the thermostat valve (which seals off colder coolant from radiator) is split which prevents the engine from getting up to full operating temperature. Both the t-stat and seal are easily replaced.
There could be an air lock in the coolant system around the engine block / heater core. Does the temperature gauge get up to full operating temp? There is a weep hole in the t-stat to allow coolant to slowly refill the block and heater core.
There could be an air lock in the coolant system around the engine block / heater core. Does the temperature gauge get up to full operating temp? There is a weep hole in the t-stat to allow coolant to slowly refill the block and heater core.
Last edited by Tom57; 12-20-16 at 10:47 AM.
12-23-16, 06:37 PM
#23
The thermostat may be stuck open or the rubber seal around the thermostat valve (which seals off colder coolant from radiator) is split which prevents the engine from getting up to full operating temperature. Both the t-stat and seal are easily replaced.
There could be an air lock in the coolant system around the engine block / heater core. Does the temperature gauge get up to full operating temp? There is a weep hole in the t-stat to allow coolant to slowly refill the block and heater core.
There could be an air lock in the coolant system around the engine block / heater core. Does the temperature gauge get up to full operating temp? There is a weep hole in the t-stat to allow coolant to slowly refill the block and heater core.
12-24-16, 09:32 AM
#24
Pole Position
11-29-18, 03:25 PM
#25
My 2003 base LS430 blows fairly cold air on idle, warms up slightly when driving. Temp gauge stays very near the low end, never toward the middle like normal, even when driving for 30 minutes. I'm going for t-stat change first (cheapest,first, right?).
BTW, I've got 249,000 miles on her. Bought it with 119,000 and haven't changed t-stat yet.
BTW, I've got 249,000 miles on her. Bought it with 119,000 and haven't changed t-stat yet.
12-05-18, 12:59 PM
#26
Driver School Candidate
Join Date: Jul 2018
Location: CA
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It's just recently that our temps in SoCal have dropped to the point of needing heat in the car. My wife came in last evening with an "A/C only, no heat" complaint, thus I've found this thread.
The low coolant theory rings truest in my ears, so that's my first direction. It's raining today, so won't get to it until Friday, but I'll report back if I find something.
The low coolant theory rings truest in my ears, so that's my first direction. It's raining today, so won't get to it until Friday, but I'll report back if I find something.
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thomashmc1
IS - 2nd Gen (2006-2013)
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12-18-17 07:29 PM
