VSV Question

[Grandavi]

Okay, so as my engine is back in the car and all the hoses/wires getting repaired/replaced/upgraded, I notice that my VSV is "bypassed".
Apparently, the solenoid on the bottom of the unit is prone to failure over time. So the quick fix is to connect the vacuum hose that come from the driver side of the engine bay directly to the VSV and just leave the solenoid vacuum lines unplugged. This seems to disable the solenoid which allows the heated coolant to flow through your heater core all the time. (which may explain my warm feet after a long drive)

I see to test the solenoid I simply start the car and set it to AUTO and put it on its coldest setting. This should retract the rod to its "shortest" size (or up) to close the valve if I am correct.
Then when I turn up the heat in the car it should extend the control rod. (Pretty sure thats how its meant to function)

I priced out the solenoid replacement and its a LOT here... over 200 bucks.

Also, in my 1990 7MGTE A/T, I had the problem with the heat only engaging if I am revving over 1000 RPM. If I idle, it starts blowing cold air. For winter.. I bypassed the VSV solenoid. (Seems to fix that issue)
I have 3 MK3's and 2 of them have this fault.. which is why I think its a common failure.

Is there any fixes to this? Just thinking there may be because I believe it is a common issue.

 

[Grandavi]

Hmm... came across this in SOGI.... (think its an old article, but may still be valid...)

Article:
Authored by: Dr. Joseph Armstrong

Tools Required: Phillips Screwdriver, Solderless Connector crimper

Skills Required: Basic Skills

If you want your fix to remain "stock" in terms of looks, you can replace your old VSV with Toyota part # 88690-32280. It's from a Camry (I believe) and is virtually identical to the original stock one. Only thing you'll have to do is cut off the leads from the old VSV and attach to the new one with solderless connectors. Again, follow the previous article to see how to do this. The new unit comes with a bracket that you can discard, and mount the new one to the stock heater diaphragm valve just like the old one.


kk, premature thread... lol.. I think I found all my answers from google, etc.. : )

 

[jetjock]

You are correct about how it works in that the VSV is closed when the temp is set to 65 and open when set to anything above although the coolant valve is designed to permit minute flow even when closed. Like all cars with such a valve its for MAX AC and testing on my car showed leaving it open costs 5--10 degrees of AC goodness.

That said the VSV can be replaced with any 12 vdc three way, automotive or otherwise. After the second one died on me (failure mode usually involves the molded coil) I replaced it with a sub-miniature industrial three way from ebay. $16 Iirc. It even bolted up to the stock bracket. End of problem.

The coolant valve itself can be replaced with a much less expansive than dealer one from 90s Corollas and Geo Prizms.

 

[Grandavi]

Does the coolant valve have any history of failure? From what I can see, it looks pretty solid, although I would guess eventually it may leak from the valve pivot. Haven't seen one failed.

 

[jetjock]

They do. Most fail at the hose connections where it gets brittle and cracks. The problem is Toyota doesn't sell the valve alone. It only comes with the bracket and actuator making it around $150. The Corolla/Prizm valve can be had aftermarket for about $30.

 

[CyFi6]

The plastic gets brittle and cracks, I have seen the ends break off. I ended up buying the Geo version of the valve but if I could do it again I would probably try to find an OEM one. The valve body itself is actually a bit larger, so you have to bend the stock bracket just slightly and it seems to make the valve stay cracked open farther than stock when in the fully closed position. The hose fittings are also slightly larger than stock but that really isn't an issue, just have to push the hose on a little harder. BTW when I bought the Geo valve it was sold by FourSeasons but was stamped wit Denso's name on it.

 

[Grandavi]

very good to know.. thank you!