Thermostat replacement questions

So I replaced my thermostat today and it was fairly easy to do . My question is what temp should the truck run at ? It WAS running at about 194 and fluctuating between 190- 195.8 (ultra gauge temp) for years this way . The new one is running 183ish , fluctuating between 178-185 . I pulled the front end of the truck up on a curb to get the front end higher and ran the rpms at 2000-2500 to heat it up while running the defrost on high (temp selector was on hot) and I also ran the truck down the highway and went for a drive . All total the truck ran for over and hour and the temp isn’t coming up .

do I have a bad air pocket somewhere probably or is that the temp of the new thermostat ?

I also drained the coolant into a clean new bucket, i did a drain and fill a few months ago (I know I should have done the thermostat then) . I did reuse it thou which SHOULD be ok right ? I was careful not to get any dirt or contaminates in it

 

If you still have the box the new one came in, it should have a temperature or part number you could look up to see what temperature it is. You might also find a temperature or part number on the old one. Most vehicles, one warm up, cool down overnight cycle, top off reservoir again, your good. Someone will possibly have a Tacoma specific instruction.

Why did you need to replace it? Mileage, 4 or 6 cyl? Useage, city, hwy, drive like granny, drive like its stolen?

 

It was a stock Toyota thermostat from my local dealer which just came in the typical Toyota bag with a part # and other unknown numbers . I have the 4.0 V6 in my truck , with 126k on it . I noticed it wasn’t keeping up to temp like it usually does , it was dropping slightly below where it usually ran and seemed to be taking longer to heat up in the mornings .

 

It should be a 180° thermostat so it should be around there.

 

Oh really ? Hmm I wonder why the stock one (that’s what I took out, it was probably original) ran at 190-195 range typically right at 194 was average and in the heat of the summer it wouldn’t go above 195.8 on the ultra gauge

 

Part number

$50 160310P010 TOYOTA Genuine Parts - Inlet Sub-Assy, Wate (16031-0P010)

160310P010

 

Also is my fan supposed to run constantly ?

 

Could be a number of reasons why. I'd consider it all pretty tolerable. But thermostats typically come in either 160° or 180° varieties.

If your fan is attached to the motor, then yes.

 

All the aftermarket thermostats (including the one made by Toyota-owned Aisin) are listed with 180F opening temp: https://www.rockauto.com/en/catalog...ystem,thermostat+housing+/+water+outlet,10337

The fan is on a viscous coupling to the belt-driven water pump, so it either runs at full engine speed (usually audible on engine startup) or a subset of engine speed.

 

Mine is still stock and runs consistently between the temps of 185-190. Sounds like you should be golden.

 

Hmm so I guess just check it later and top off if necessary ? Weird that it’s always run hotter .

yes I can hear the fan is usually louder with initial start up , I thought it was only supposed to run when the motor was over temp and then shut down? I guess not huh

 

When you burped the system, did you turn the heater to max?

A leak-free funnel like this one helps greatly with burping the system, if you aren't using one already.

 

Yes heater was a max heat , parked up on a curb , ran engine at 2000-2500 rpm to bring up temp . I noticed when the coolant went into heater core because the air initially wasn’t hot coming out of the vents

that’s how you burp it right ?

 

Yeah that's fine. The Tacoma cooling system is fairly straightforward, compared to some other vehicles like the MR2.

 

So I’m good to go it sounds , I got a 180 degree thermostat and that’s what it’s running . I’ll check the level later , any bad bubbles should work themselves out I imagine ?

 

I'm sure there's some burping procedure I don't follow. This is what I do. I'll fill radiator until there's still a little air at the top. Then repeatedly squeeze the hoses. It pushes air out, coolant in. Some water pumps have a bleeder screw on top to get any trapped air out. Unscrew, if it's a plastic petcock* it'll have a slot so you don't have to completely remove it. If it's a bolt, I've had to take it all the way out. Be ready to immediately put it back in, just takes a second ot two before it squirts coolant. Tighten the bolt, if plastic don't overtighten, the rubber gasket will mush out & leak. Top off radiator, fill reservoir to between the low & full marks. Clean spilled coolant off anywhere it could leak from with brake cleaner and ari blow gun. Start it up, turn heater on, turn engine off. Look for leaks, easy to forget to tighten a hose clamp. I'll use a mirror and flashlight to look on the backside of stuff, under the water pump. Start it up, heater on, brit up to full temperature, thermostat opens and closes at least once. Next day fill reservoir to cold line or hot upper line if already driven. I don't reuse coolant because it always washes some dirt & crap off & into the drain pan. It sounds like your certain it was clean so you're fine. This is what I do, and won't be offended if someone needs to correct me.

*Some of those old plastic petcocks, you look at it too hard the handle will snap off. Drill, extract, run a tap in if needed, new petcock & gasket can be got at any auto parts store.

The above funnel, I have a similar one by lisle. It does a wierd glop glop thing and squirts coolant straight up. I hold the stopper stick just above the hole so it doesn't squirt out. I have some pinch off pliers, I think they're gearwrench 3793 , they work great to keep some of the coolant in. I had some by otc but they stopped holding. Theres also cheaper plastic ones. For stuck hose removal theres hose picks. I also have a funny thing by astro pneumatic that grabs the hose so you can twist and pull on it.