Heater Control Valve

[Tote]

Hello, I recently (2 Months ago) had my timing belt changed and the mechanic inspected my car and said the heater control valve had a leak. I told him to skip it as the part alone was over $140. at his price. I saw the part and it did look like fluid had leaked and dried. I can't really tell, it almost looks like it is coming from the hose underneath. None the less, I now want to change it and wanted to know if I should be aware of anything before I try to take on this project? It seems stright forward. It seems as if I should be able to change the hoses attached to the heater control valve as well.

I checked out newlexusparts.com and they had this listed

CONTROL valve, LS400 90-94 $65.06

Hvac - Heater - Control valve

Is control Valve same as heater control Valve? If so is that site and price decent? I haven't called the dealer for a quote yet, cause they always make me sick to my stomach. Espeacially if I can do it myself.

Any Info would be appreciated

Tote

1990 Ls400

[wwest]

The 90-94 series, insofar as I know, only has one heater, hot water, control valve, mounted at the top center of the firewall within the engine compartment.

It is very likely a really easy DIY project and the control cable from the airflow mixing vane servomotor slips on and/or off quite easily and doesn't really need calibration, just be sure it's at the full closed position in max cool.

As an aside, I remove the control cable during the summer months and tie the valve into the fully closed position. Improved cooling efficiency and slightly better MPG.

If you're not seeing an substantial level of antifreeze loss you might be looking at simple seepage which is hard to avoid for a car this old.

[bartkat]

As an aside, I remove the control cable during the summer months and tie the valve into the fully closed position. Improved cooling efficiency and slightly better MPG.

That's a great idea. :)

[mickg]

As an aside, I remove the control cable during the summer months and tie the valve into the fully closed position. Improved cooling efficiency and slightly better MPG.

That's a great idea. :)

←

I just did my '94 heater control valve. Very simple DIY job. Same part price, local shop wanted $200 to change it out.

Mick

[arsvivendi]

I just did my '94 heater control valve. Very simple DIY job. Same part price, local shop wanted $200 to change it out.

Hi

I have 93 Lexus LS400,Problem with Heater Control Valve:Leaking coolant currently. Anyone has information how to remove and install it?

Thanks.

[pgupta]

I just did my '94 heater control valve. Very simple DIY job. Same part price, local shop wanted $200 to change it out.

Hi

I have 93 Lexus LS400,Problem with Heater Control Valve:Leaking coolant currently. Anyone has information how to remove and install it?

Thanks.

←

It is quite straigthforward. One of the hose clamps is rather funky. You have to "unwind" it to make it loose. Spray some WD-40 all over, makes slipping the hoses out a little easier. The leaking coolant corrodes the parts underneath and is a good idea to replace the valve. I bought mine from irontoad.com for about $70 including shipping.

[Lexls]

The hardest part will probably be getting the old one off. Basic steps...

1) Drain coolant

2) Remove valve

3) Install new valve

4) Fill coolant

[arsvivendi]

Thank you all you guys!

I order heater valve today. I will update pics of "before and after".

[pgupta]

The hardest part will probably be getting the old one off.  Basic steps...

1) Drain coolant

2) Remove valve

3) Install new valve

4) Fill coolant

←

No need to drain coolant! The valve is at the highest point of the coolant circuit. Draining the coolant will be a bigger chore than replacing the valve. My two cents!

[Lexls]

No need to drain coolant! The valve is at the highest point of the coolant circuit. Draining the coolant will be a bigger chore than replacing the valve. My two cents!

←

Even though it's at the top I would think a bunch of coolant would spill out.... Have you done this without draining the coolant or is this just a hunch? Doesn't make much difference to me, just wondering :whistles: .

[wwest]

What is your definition of a "bunch"??

In this case mine would be "no more that a quart". Just don't do it with the water jacket hot and/or therefore pressurized. Open the radiator cap, gently, first.

[pgupta]

No need to drain coolant! The valve is at the highest point of the coolant circuit. Draining the coolant will be a bigger chore than replacing the valve. My two cents!

←

Even though it's at the top I would think a bunch of coolant would spill out.... Have you done this without draining the coolant or is this just a hunch? Doesn't make much difference to me, just wondering :whistles: .

←

I have done it without draining and don't remember if a cup full was lost or a few teaspoons! I just shoved a rag underneath the valve before starting and don't remember it being dripping wet.