Changed Thermostat...still No Heat Blowing Cold

[wuzzy1]

Greetings Gents and Ladies,

Started out on a 600 mile trip and found cold air blowing with the heater on.

Was going to cancel the trip, didn't want to get sick, drove 40 miles stopped

in a lube shop asked to use a hammer, tapped the area of the thermostat

heat worked okay for the trip.

Got to where I was going, purchased and put in a new 185 degree thermostat

and the heat worked okay.

Took a drive tonight, Saturday, and...NO HEAT...blowing cold again.

Gotta' return Monday...needless to say I'm baffled.

Anybody got any ideas?

PLEASE SAVE ME FROM A COLD RETURN TRIP!

[4howard]

Greetings Gents and Ladies,

Started out on a 600 mile trip and found cold air blowing with the heater on.

Was going to cancel the trip, didn't want to get sick, drove 40 miles stopped

in a lube shop asked to use a hammer, tapped the area of the thermostat

heat worked okay for the trip.

Got to where I was going, purchased and put in a new 185 degree thermostat

and the heat worked okay.

Took a drive tonight, Saturday, and...NO HEAT...blowing cold again.

Gotta' return Monday...needless to say I'm baffled.

Anybody got any ideas?

PLEASE SAVE ME FROM A COLD RETURN TRIP!

Had the no heat problem in my 95 LS400. Make sure you have the coolant filled to the proper level. You will need to be sure there is no air in the system, on my car this required the car to be put on a lift with the front raised higher than the rear to force the air up and out of the radiator. Finally, make sure all the seals are tight - especially the one on the plastic overflow tank. If the gasket on the overflow cap is broken or cracked or missing, you could be getting air in the system. Good luck.

[landar]

Greetings Gents and Ladies,

Started out on a 600 mile trip and found cold air blowing with the heater on.

Was going to cancel the trip, didn't want to get sick, drove 40 miles stopped

in a lube shop asked to use a hammer, tapped the area of the thermostat

heat worked okay for the trip.

Got to where I was going, purchased and put in a new 185 degree thermostat

and the heat worked okay.

Took a drive tonight, Saturday, and...NO HEAT...blowing cold again.

Gotta' return Monday...needless to say I'm baffled.

Anybody got any ideas?

PLEASE SAVE ME FROM A COLD RETURN TRIP!

Most likely is air trapped in the system. First thing I would do is put on a new radiator cap. Perhaps your old one is

not keeping the system properly pressurized. And that may not allow the system to purge the air.

[AzHotLS]

Hopefully it's not a blocked heater core.

Another thing to check is the valve that allows water into the heater core. There's a cable that moves the valve and it possibly has come off. The valve is up high back on the firewall. You should see it with no trouble. If the cable is off, the valve isn't opening so no hot water into the core. Here is what it looks like:

http://www.clublexus.com/forums/ls400/6496...what-is-it.html

However, if it is because of air in the system, instructions for "burping" or purging the air from the coolant system should be printed on a label on top of the reservoir. Or follow the instructions here:

http://us.lexusownersclub.com/forums/index...st&p=354605

[Acidic]

I would check the coolant level, then burp the system... if that doesn't fix it find the feeder hoses for the heater core. Use a garden hose or some other sort of water source that provides a little pressure and blow out the core with it... then refill and burp the system....

when you are "burping" sit in the car and moving the heat from full hot to full cold several times while the car is running