I have no idea what this part is on the cooling system

General discussion about our beloved Tercel 4WD cars
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conantm2
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My tercel:: 1985 sr5 4wd wagon
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I have no idea what this part is on the cooling system

Post by conantm2 »

Hey guys, new member here my names Mike. I just picked up a 1985 Tercel 4wd for an absolutely incredible deal. Anyways I’m trying to learn as much about them but I’ve never seen this part on a car before. It looks like it’s a sensor or proportioning valve of some sort. It’s on the housing of where one of the coolant lines comes in. Has 3 air hoses going into it. It’s missing on mine because I found it on a 1986 Tercel coupe at the junkyard. I’m wondering will that one Work for my 85? I’ve attached a picture of the one on the 86. Thanks for any and all help!!
CA23B60F-22FF-4DDE-B254-635B6103FC22.jpeg
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NWMO
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Re: I have no idea what this part is on the cooling system

Post by NWMO »

Congrats Mike and welcome to the forum. That part is called the TVSV (thermomatic vacuum switching valve) and would work on your car. They tend to be easily damaged during removal, but that one will fit fine. There is an interesting post about them on the front page of the “parts” section of the forum.

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Rednecklawrence
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Re: I have no idea what this part is on the cooling system

Post by Rednecklawrence »

I once merely poked one and it broke... Careful with those stupid things
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Petros
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My tercel:: '84 Tercel4wd w/extensive mods
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Re: I have no idea what this part is on the cooling system

Post by Petros »

welcome to the forum,

how does it run with it? Unless someone installed a weber carb (which means you do not need it), that item is difficult to make it run well with out it. It turns on and off certain parts of the emissions and fuel system as the car warms up. It would be near undrivable when it is first started and stone cold. It can be rigged to run without after it warms up. but before warm up, it will be stumbling and cofing every time to try and drive it.
'87 Tercel 4wd SR5 (current engine swap project)
'84 Tercel 4wd (daily driver, with on going mods)
'92 Mazda MPV 4wd (wife's daily driver)
'85 Tercel 4wd DLX auto(daughter's daily driver)
'01 Honda Civic (other daughter's daily driver)
conantm2
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Joined: Wed Dec 06, 2017 9:56 am
My tercel:: 1985 sr5 4wd wagon
Location: Monroe, wa

Re: I have no idea what this part is on the cooling system

Post by conantm2 »

Thanks for the help guys!! It runs great without it sometimes it takes a minute to start when she’s stone cold. I actually lucked out and found that 86 at a local junkyard and was able to pull the switch from it without breaking it. I just installed it on mine tonight and believe I have Plummed it in correctly. I’m going to start it back up in the morning to see if I succeeded :) . Clock says it has 320,000 on it but it runs really well.
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Petros
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Re: I have no idea what this part is on the cooling system

Post by Petros »

did you get all of the vac lines for it when you got the TVSV?
'87 Tercel 4wd SR5 (current engine swap project)
'84 Tercel 4wd (daily driver, with on going mods)
'92 Mazda MPV 4wd (wife's daily driver)
'85 Tercel 4wd DLX auto(daughter's daily driver)
'01 Honda Civic (other daughter's daily driver)
conantm2
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Posts: 5
Joined: Wed Dec 06, 2017 9:56 am
My tercel:: 1985 sr5 4wd wagon
Location: Monroe, wa

Re: I have no idea what this part is on the cooling system

Post by conantm2 »

Petros- yes I got all the vacuum lines from the 1986 at the junkyard. I actually just scored a bunch of spare parts from someone off of craigslist and they had another TVSV in it as well. I got several carburetors and distributors now if anyone needs one.
TVSV.JPG
Here it is plumbed in on my tercel.


Also I noticed that it looks like the top portion of my timing cover seal is missing, this was kind of alarming.
Timing cover.jpg
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Petros
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Re: I have no idea what this part is on the cooling system

Post by Petros »

actually that is not a seal for the valve cover, it is just so dust does not get into the timing belt area. No harm will come without it, most of the Tercels I have owned had this gap seal missing.

It has become popular with the street ricer crowd to install bright green or purple timing belts with bright anaodized sprokets, and then leave the whole front cover off to show it off. Not a good idea because sand and gravel can get kicked up and it will errode away the belt and pulleys. of course this is not such a big deal if you only drive on clean pavement, but I drive steep gravel roads daily and found my fan belt getting chewed up by sand and gravel anyway (one reason to keep the plastic splash pan on under the engine, but I find that a nuisance when I want to work on my engine). Also, having all those rotating parts exposed while you are working on the engine can be a hazard, particularly when setting the timing where you have the light and loose wires exposed in the engine compartment while it is running.

If you are really concerted you can put a piece of duct tape over the gap, but I never worry about it.

having a good working spare distributor assembly is important, it is useful as a diagnostic tool. if you suspect somethign in the distributor assembly (which contains the coil, ignitor, and capacitor), you just swap it out to see if your symtom goes away. I had done this recently, it was getting hard to start on cold damp mornings, I suspect a compromised coil (allow misture inside the case). I swap out my spare distributor assembly, and the problem went away. Faster than testing it, and certinaly faster than taking it all apart to inspect for cracks. I usually try to carry a spare distributor on long trips for the same reason. With it being all in one, you only need the one assembly to have spares for all of the components.

good luck
'87 Tercel 4wd SR5 (current engine swap project)
'84 Tercel 4wd (daily driver, with on going mods)
'92 Mazda MPV 4wd (wife's daily driver)
'85 Tercel 4wd DLX auto(daughter's daily driver)
'01 Honda Civic (other daughter's daily driver)
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Rednecklawrence
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My tercel:: 5.5 Tercels total... Not enough

Re: I have no idea what this part is on the cooling system

Post by Rednecklawrence »

Petros wrote: Mon Dec 11, 2017 2:05 pm having a good working spare distributor assembly is important, it is useful as a diagnostic tool. if you suspect somethign in the distributor assembly (which contains the coil, ignitor, and capacitor), you just swap it out to see if your symtom goes away.
Yeah when I got my green tercel it left me on the road 3 times due to a bad ignitor. wish I had a spare distributor then :?
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