KahnBB6

iTrader: (5)

Update on my Everco (aka Four Seasons) #74636 notes:

I'm not sure why but today when I went to look up this part again I find it seems to be hard to order from most of the usual auto parts stores or even from Amazon. I do see them available on eBay under another name with the same part number (with the claim they are made in Japan, btw).

Curiously I have found another model come up in a search for "2000 Toyota Sienna heater control valve" (the 74636 valve is intended for a 1998-2000 Sienna) which is 74646 but there was the note that it would not fit the Sienna. The difference appears to be the lack of additional bracing on the side of the valve that we DON'T want, so there's that plus of not having to modify it externally.

The arm still needs to be swapped and without having the 74646 in front of me I can't tell if the mounting point allows the OEM SC metal arm to rotate the valve to open and close in the same way our OEM valve does.

It may be a worth investigating this one to see if it works, since this model appears to be easier to source as of 2017 than the Everco/Four Seasons 74636 valve.

SDGSPW

Just so everyone knows, it looks like the Four Seasons/Everco part 74636 has been replaced by Murray part 74636. It shows still available at O-Rilley's.

KahnBB6

iTrader: (5)

^^ Good catch! Thank you!

tylerlinn5

I was able to purchase the Motorcraft YG-368 part O.L.T. mentioned for $27 same day pick-up from a local Ford dealers parts department. If anyone is in a rush, I would go this route. Most of the alternatives need to be shipped in.

RudysSC

OLT you're the man. I recently noticed that my valve had started to leak and began doing research. I'll be replacing my OEM part with the Motorcraft option and doing all heater hoses as the same time. Thank you for the excellent DIY.

wsaharem

Had a mechanic said he would not work on my car because it was leaking from the heater vacuum valve. I signed up for the $520 repair job, then found the $20 solution on this thread. Quickly called and cancelled. (thankfully he had not yet ordered the part).

I appreciate the DIY from OLT and further invesigation from KahnBB6. I unfortunately went the Volvo route because I do think Volvo makes quality parts, and it was $16. I say unfortunately because the Volvo valve is backwards for the SC300. IE, when heat is on, the valve is closed and when temp is low or Air conditioning is on, the valve is open. Also, the diameter of the male part is smaller on the Volvo part, but was able to clamp it ok.

So I'll be going back to purchase the Motocraft version since I've removed the vacuum assembly from the car. I've included a couple of pictures for the folks that asked for pictures of how it looks after it's completed.

Before

The "wrong" volvo part.

Purchased the elbow and a replacement hose because the current one is old and it needed to be longer.


Small .614. Volvo part wrong on 2 fronts.

Original at .679 (5/8)

After. All installed

KahnBB6

iTrader: (5)

Excellent work, wsaharem! Definitely if the Volvo part's valve arm operates in the opposite direction then O.L.T.'s Ford Motorcraft valve solution will be your best bet with this style fix.

I don't take full credit for the Everco/Four Seasons 74636 valve. Another member a few pages back initially came up with a big list of possibly compatible valves that he had not tested. I just followed his list and tried every one of them until one proved to work like the stock one (albeit requiring some Dremel shaving on one side). For reference I haven't tried it yet but the next OEM-like valve to try is the Everco/Four Seasons #74646 (for a 1998-2000 Toyota Sienna Minivan) as it is also shaped like the OEM Lexus SC valve. It has yet to be tired out by anyone to see if it works like the Everco/Four Seasons #74636 with or without any modifications besides swapping over the OEM HCV valve arm. So far the only model number of that style heater control valve that I've personally tested to work correctly is the 74636.

Nonetheless your work is neat and clean! Thank you for taking the time to gather pictures and measure to demonstrate the thicknesses of the inlet and exit pipes and your adapters!

Gears12

Thanks to all who worked on this mod. I greatly appreciate your effort. Let me give back to the Forum by saying I just got through putting on a Four Seasons 74646 valve from Rock Auto on my Lexus SC300. I could not find a Four Seasons 74636 valve anywhere and it appears to be discontinued? OK, Did the 74646 work: Yes. Was it easy to do or a bolt on: No. Would I do it again, and should others try this: IMHO, No.
Here's the good and the bad about the 74646 valve.

The Good:
The inlet and outlet piping are at a right angle, like the Lexus valve.
The inlet and outlet piping are the same sizes as the Lexus valve.
Water flow through the valve is in the same direction according to the arrows
The valve arm shuts in the same direction as compared to the Lexus valve
The Lexus valve arm screws right on (and will need to be swapped)

The Bad:
The mounting points for the valve are on the wrong side! They are on the opposite side they need to be.

This "Bad" point is a biggy because I had to cut off the back half of the mount to get it to fit in the metal Lexus mount. Then, I had to fabricate a 1/4" thick spacer to take up the bottom gap between the water valve and the metal frame. Lastly, now how do you mount the valve to the metal frame? The screw holes are on the wrong side, facing up and are pretty much useless. I ended up cable tieing the valve to the frame. Since the valve ends up being wedged in the frame snuggly and the 1/4" spacer gives it a tight fit, it ended up working out for me. Keep in mind I had already cut 1/2 of the mount off at this point so I couldn't return the valve. Also, my old valve was leaking and my car was apart so I didn't have anything to lose by trying this. If the cable ties don't hold, then at least my car wont leak until I get different valve. It is working however.

So again, I don't recommend using the 74646 valve. It appears from this thread that there are easier alternatives. I will mention two other valves if someone wants to look into them. From O'Reilly's site: Murray 74637 or Murray 74641. These valves look better than the 74646 as the mounting point appears to be right. One thing to check on is it appears these valves close in the opposite direction as the Lexus valve.

I hope this helps,
Gears

KahnBB6

iTrader: (5)

^^ Just chiming in here with both some examples of a Four Seasons 74636 valve installed in my spare HCV assembly but also to pose the possibility that Four Seasons perhaps made a revision to the 74636 since the time I bought one and tested it in my car. That revision may well have been to remove the mounting points that we DO need to fit these into an SC. A few years ago when I used a 74636 valve I did have to Dremel off the mounting posts on the side that we do not need. And I had to re-used the original swivel arm and locking washer from my old broken Lexus valve. Those were the only changes needed at the time.

I just pulled out my spare HCV assembly which has a working Four Seasons #74636 valve installed into it. Note that it DOES mount correctly but that I had to Dremel off some material on the other side to get it to clear the metal frame on that side. Also note the swapped over swivel arm from the old Lexus valve.

The original DIY guide post in this thread that I made for the #74636 (which has since that time apparently been revised?):

https://www.clublexus.com/forums/per...ml#post8587609











Gears12, from what you have reported to us it appears that Four Seasons (or whichever company manufactures and supplies this part to them) has removed the mounting points required to get it bolted in to an SC. If so... that is a very unfortunate revision because it means that unless someone buys a new old stock earlier version of the #74636 then it can't be used. I hope that is not the case but it seems to be so from what you've said.

Further back in this thread I listed some Four Seasons valves that another CL member tested before me and a few other Four Seasons valves that I tested after him... one of which included the #74636. It was the only one of the bunch that had the potential to mount correctly (with some minor housing modification), which routed the hoses correctly and had the correct rotation direction and correct rotation angle.

If anyone happens to find a #74636 with the mounting points on BOTH sides then that is the revision of it that can be modified to bolt right in like the stock Lexus valve. Assuming any are still out there. However with nothing to indicate a revision one would never know which version they are buying.

If memory serves I did not buy and try the #74637 or #74641 but I will go back into this thread and see what my old notes said.

Edit:

I found my old research which actually DID include the Everco / Four Seasons #74641 and #74637. Unfortunately both of them were close but had compatibility issues that the #74636 didn't have:

https://www.clublexus.com/forums/per...ml#post8323504


Overall this thread is important because it gives SC owners options to service and replace their HCV. The near-stock #74636 *was* a good option when I tested it out back in 2013-2014 or so and later but so are many of the other options that came before it such as O.L.T.'s Ford Motorcraft valve fix. And I think there was someone who tried a Volvo HCV as a replacement.

Gears12

Thanks for your reply KahnBB6.

I just wanted to be clear that I was posting on the 74646 valve not the 74636 valve. Believe me, I wish I could have found a 74636 valve, but I really think its discontinued at this time. If someone can find the 74636, please post where they can get it because I believe it would be the best way to go.

Thanks again

KahnBB6

iTrader: (5)

Gears12, my apologies if I misunderstood your post as referencing the #74636 valve when you meant the #74646 valve. That the '36 is discontinued now is very disappointing. When I had checked doing research on it a few years ago it seemed to cross-reference to some 90's model years of the Toyota Sienna minivan. Maybe the target market for it died out ?

I wish I could suggest some way to internally modify any of the other valves (#74641, #74646, #74637, #74004) for proper arm rotation but I don't recommend breaking them open unless someone knows a proven and surefire way to re-seal the plastic housing in order to continually withstand hot coolant running through it for years. The only other method that comes to mind (and so far not attempted) is to modify or machine a new arm that mimics the Lexus valve arm but which can work with the plastic valve keyway impression ( ">") on one of those valves that rotate in the wrong direction for SC's.

The Lexus arm mounted on any of those won't allow the valve to fully close or open because the arm hits the wrong side of the SC300/400 HCV bracket assembly.

It's been a while since I've dealt with it but thinking out loud here (and without further experiments or evidence to go on) it may be possible to have a new arm made that fits the opposite keyway indentation and which uses an extension of some kind to work correctly with the SC's HCV diaphragm plunger.

At that point it's fast getting into the same territory as adapting O.L.T.'s Ford Motorcraft HCV valve but theoretically it might be possible. However all those other wrong-rotation valves would have to be experimented with and a new arm would have to be made available through some means.

...

Another thought would be to simply measure and design a simple flip-around mounting adapter bracket to mount any of those wrong-rotation valves so long as the correct arm rotation with the Lexus HCV arm, with such an adapter bracket plate change, could be achieved.

^^ Honestly getting a simple flip-around mounting bracket figured out for that purpose would seem to be the best and easiest idea at this point for these "almost like OEM" HCV valves since the #74636 has become a discontinued item :/

But, again, I haven't tried this yet with any of the other valves in the list. The '36 was such an easy solution since it presented the least number of compatibility obstacles compared to stock.

renokev

The Motorcraft YG-368 valve works, but, I decided to not use the old mounting bracket. Didn't really need it and it can go in the box of parts. The problem lies in simply trying to reverse the valve flow direction and hoping on the cold setting being the new hot and vice versa. The valve opens perfectly (now on the cold setting), but the blend door, flapper, or whatever you want to call it doesnt work properly, since the car recognizes that the dash setting is on cold, and prevents the air flow from being routed through the heater core. So even though the setting is on cold, and the valve is wide open, once again-no heat.
So you will have to modify the original arm and spin it around to the other side as previously mentioned. This is kind of a pain, but works fine. Just be aware its not just a simple reversal of flow direction. I used a little shoe goo on the screw holding the modified arm on since its just a screw into plastic. One last thing, if your switching out the vacuum hose leading to the diaphragm, be aware that mine had a small brass reducer inside the original hose, that could easily be overlooked.
92sc300. 315k miles.

GAsc300

I posted a question and answer elsewhere on site about this but it also applies here…

I think I’ve figured out my own answer to dealing with aftermarket heater control valves. Importantly, Only the oem piece has the eletrical connection hanging off it to plug into car’s switch.

So No matter which cheaper replacement you choose you have to deal with fact that Lexus SC300’s electrical switch doesn’t have a way to connect to the new part(s). this switch controls the function of the heater control valve, so without it the new valve will always be open or always closed. Period.

that probably explains the varying experience of past members who connected one replacement heater control valve or another. They either had constant flow into heater core or no real flow. Since none of the non oem replacements connect to this switch they will be open or closed based on their default design (some start off always open or always closed).

if this is correct then you might as well move the heater control arm lever by hand to being always opened or always closed, based on the season. Nothing in the car can control it without the switch connected. Or just by bypass the faulty heater control valve completely and basically have it always opened and always flowing into heater core.

kolbe

Nothnghead

^
I’ve found this to be true for my ‘92. I change routing if the vacuum lines in the spring and fall as appropriate. I wonder if there are any solenoids that could be swapped in to activate the vacuum control valve.

GAsc300

thanks for reply…

We’d really be just as good replacing the whole heater control valve with a piece of piping with a lever on top to open or close flow. These replacement heater control parts do nothing this wouldn’t do.

Yesterday I ended up bypassing the whole heater control valve and heater core too using existing coolant lines plus some 5/8 inch barbed connectors. Drove car few times no leaks and good temperatures. No heat of course since i bypassed both.