94 SC400 Heater Control Valve?
Alright well I noticed something wierd. I definitely have a bad heater control valve. I bypass it for the winter and the heat works, otherwise it doesn't. But the heat will only get hot if the engine is over around 2000RPM. Under that (so cruising or idling) the heater blows cold air. AC button is off. Outside temp is around 50*. Can't figure out what this would be?
Lead Lap
Joined: Jan 2004
Posts: 539
Likes: 0
From: Ohio
My 94 SC4 just had the same problem. There is a diag test for the VSV which controls the actuator on the water control valve. However there is a simpler test. If you take the vacuum hose from the VSV and plug it directly into the actuator and you now get heat (engine warm, wait a minute or two), then your VSV is bad. See the two photos below. First photo is how the vacuum hoses should be routed. Second photo is the re-routed hose directly to the actuator. A local lexus gave me the following part numbers 88690-24060 ($225) for the VSV and 87240-24040 ($325) for the whole water control valve unit. It's much less at Carson's and I just ordered my VSV today. By the way, if you keep the hoses rerouted, you'll lose cooling efficiency when it gets warm outside but it's a good alternative until the replacement part(s) come in.
Would buy you a beer if you were from around here.
Driver School Candidate
Joined: Nov 2011
Posts: 2
Likes: 0
From: Texas
Saved $865 Heater Control Valve Replacement by Lexus Dealer. After reviewing your pictures, I tested the valve by changes hose connections as instructed. Heat came on. However the short hose 45 degree hose has a plastic connector. I removed it and found the connector was collapsed. Replace the connector with a piece of hose I had lying around and it now works like new. So, before replacing the Heater Control Valve check the short 45 degree hose connection for clogging or collapse.
Pole Position
Joined: Aug 2006
Posts: 311
Likes: 1
From: FL
Hello all 
I'm in a similar situation with my Heater Control Valve. But in my case, the water inlet has broken off of the housing of the valve it's self. In the picture below you can see the inlet port circled by yellow, and where it's broken off shown in red dashed. And the blue is what I'd like to replace without having to purchase any of the other stuff which is still working.
1st, is that even possible? Buying the central plastic part ONLY. And if not - what's the deal with all these I see everywhere online as *replacements* for the whole Heater Control Valve assembly:
Because these little suckers are 20 bucks as opposed to $400.
Check this shop here it's got both:
http://www.drivewire.com/vehicle/199...control-valve/
I'm in a similar situation with my Heater Control Valve. But in my case, the water inlet has broken off of the housing of the valve it's self. In the picture below you can see the inlet port circled by yellow, and where it's broken off shown in red dashed. And the blue is what I'd like to replace without having to purchase any of the other stuff which is still working.
1st, is that even possible? Buying the central plastic part ONLY. And if not - what's the deal with all these I see everywhere online as *replacements* for the whole Heater Control Valve assembly:
Because these little suckers are 20 bucks as opposed to $400.
Check this shop here it's got both:
http://www.drivewire.com/vehicle/199...control-valve/
Pole Position
Joined: Aug 2006
Posts: 311
Likes: 1
From: FL
Pole Position
Joined: Aug 2006
Posts: 311
Likes: 1
From: FL
Anyone on this? Can anyone explain how you'd integrate this little 20 dollar part in place of the central plastic valve part of the OEM assembly?
If i'm understanding this correctly, that's what the process would be if I got one of these 20 dollar parts listed / shown / linked to above.
If i'm understanding this correctly, that's what the process would be if I got one of these 20 dollar parts listed / shown / linked to above.
Lead Lap
Joined: May 2011
Posts: 485
Likes: 2
From: GA
OLT has pointed out a far cheaper replacement in this thread.
I'll go with this replacement when my valve gives up the ghost. There's no reason to hang onto a Lexus branded part for something as simple as this.
I'll go with this replacement when my valve gives up the ghost. There's no reason to hang onto a Lexus branded part for something as simple as this.
Pole Position
Joined: Aug 2006
Posts: 311
Likes: 1
From: FL
100% Genius. You and OLT are de men 'dem!
F that little metal part I'd found. And F the Denso $400 one too.
Thank you - I'm off to go find one of these now wikkid!
I'll report back here once I get one about how much it is right now end of year 2011, where from and again once it's in with any install notes and afterward operating comments.
ez ---CLRH2O
F that little metal part I'd found. And F the Denso $400 one too.
Thank you - I'm off to go find one of these now
wikkid!I'll report back here once I get one about how much it is right now end of year 2011, where from and again once it's in with any install notes and afterward operating comments.
ez ---CLRH2O
I just tried doing this now I just had my gte swap done not sure wtf happen but it looks like its not even plugged in I can't seem to find the clip that it plugs in to as well please help I'm freezing my *** off
^ make sure you have vacuum , i did the "fix" and nothing then later fiddled with it again and noticed the valve was working(by pressing on it with my finger) and then took the vacuum line off it to realize i had no vacuum at all, went straight off the manifold and viola ..heat!!
Lexus Test Driver
Joined: Jun 2004
Posts: 1,074
Likes: 0
From: Florida
How did you notice the valve was working by pressing on it? Also which line should I be checking for vacuum, the vsv line? When you found that it didnt have it, you just t'ed off one going to the manifold you're saying? Thanks in advance. It just got a little cool out here in FL didnt it?