RedLexusSC400 Posted September 15, 2005 Share Posted September 15, 2005 So going into the colder seasons I thought I would try to figure out what is going on with my heater. Earlier this year my heater stopped working so well. When I start it up it doesn't kick on at all sometimes for 5 minutes, sometimes it takes about 15... It will just blow cool air. And I know it's not that it's just warming up. Because you feel a huge difference when it does kick on. And it still works great when it's on. It gets very hot. So any ideas why it would take that time for it to actually kick on? Loose wire or something? Thank you for your help... Bryan Quote Link to comment Share on other sites More sharing options...
master Posted September 15, 2005 Share Posted September 15, 2005 Yeah i have had same problem, your thermostat is going bad bro, get this done before winter cuz you're going to freezzzzz your !Removed!, big time!!! that thing is located almost on top of engine where air box piping meets intake mainfold, don't have any pictures, sold my SC400 3 years ago with same problem at 135,000 miles :whistles: Quote Link to comment Share on other sites More sharing options...
RedLexusSC400 Posted September 15, 2005 Author Share Posted September 15, 2005 Yeah i have had same problem, your thermostat is going bad bro, get this done before winter cuz you're going to freezzzzz your !Removed!, big time!!! that thing is located almost on top of engine where air box piping meets intake mainfold, don't have any pictures, sold my SC400 3 years ago with same problem at 135,000 miles :whistles: ← Well do you have any idea what I'm looking at costwise? :( It doesn't sound so bad... Quote Link to comment Share on other sites More sharing options...
jbarhorst2 Posted September 16, 2005 Share Posted September 16, 2005 I don't think it's your thermostat. If the heat comes on all of the sudden, then I think it is your heater control valve. This controls the flow of hot water to the heater core inside the dash. The valve is easily accessed under the hood on the firewall. I replaced mine last year because it was leaking. It's not cheap. It was almost $400 for the entire assembly (valve and electronic control). My valve was leaking, but my electronic control still worked. They will sell the control separately, but if you need the valve then you must buy both in an assembly. It sounds almost like your control is going out. Let me know if you need help finding it under your hood. I can take a picture. Tom Quote Link to comment Share on other sites More sharing options...
RedLexusSC400 Posted September 16, 2005 Author Share Posted September 16, 2005 I don't think it's your thermostat.If the heat comes on all of the sudden, then I think it is your heater control valve. This controls the flow of hot water to the heater core inside the dash. The valve is easily accessed under the hood on the firewall. I replaced mine last year because it was leaking. It's not cheap. It was almost $400 for the entire assembly (valve and electronic control). My valve was leaking, but my electronic control still worked. They will sell the control separately, but if you need the valve then you must buy both in an assembly. It sounds almost like your control is going out. Let me know if you need help finding it under your hood. I can take a picture. Tom ← A picture would be great if I know what to look for... I mean is there any way to tell that it's bad without just changing it out? Quote Link to comment Share on other sites More sharing options...
jbarhorst2 Posted September 16, 2005 Share Posted September 16, 2005 You can watch it move. Unfortunately I am out of town and won't be back until Monday to be able to take a picture. If you are looking at your engine from the front of the car, the valve is on the passenger side of the firewall. You will see two hoses connected to it. They are about 1 inch hoses. It is near the top of the firewall. Go take a look and let me know if you find what I am talking about. Tom Quote Link to comment Share on other sites More sharing options...
chasrb Posted November 14, 2005 Share Posted November 14, 2005 You can watch it move.Unfortunately I am out of town and won't be back until Monday to be able to take a picture. If you are looking at your engine from the front of the car, the valve is on the passenger side of the firewall. You will see two hoses connected to it. They are about 1 inch hoses. It is near the top of the firewall. Go take a look and let me know if you find what I am talking about. Tom ← My 94 SC 400 just stopped heating the cabin too, well into the 300 USD to replace the heater control valve almost 700 USD if the dealer does it... I think I found where it is located but when I connected the two hoses together(bypass routine) I still did not get the heater to start blowing . A/C blows fine so the motor works. BTW if you can post the pic it'll help me verify I am workign on the right part. Thanks Chasman Quote Link to comment Share on other sites More sharing options...
RedLexusSC400 Posted November 16, 2005 Author Share Posted November 16, 2005 So we checked the heater control valve along with the entire heater/cooling system under the hood and everything seems to be working fine. While we saw that it worked fine my heater was not working. But then later that day it decided to come on, and like I said before, it works perfect once it decides to kick on. The mechanic I have looking at it thinks it might be an internel/electrical issue maybe? Because I turn it on and blows air, but randomly blows hot. We have also looked under the dash and the control to switch from blowing air on your feet or up top all seems to be working fine, along with the recirculation/vent control. Any other ideas would be much appriciated!!!! :cries: Bryan Quote Link to comment Share on other sites More sharing options...
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