Engine overheats, coolant level drops

Stuck thermostat will not show up on the code, but judging from how quickly your truck overheats I would say its a real possibility its either busted water pump or stuck thermostat. Did you find where leak is ? Is it possible its coming from water pump?

 

It was in the parking lot of Advance Auto when I was replacing the serpentine belt. I did not have means to look into it more closely as to find the actual hole. I plan to get back to working on it tonight. I have ordered a pump kit with valve adapters to pressure test the coolant system, hope it gets here some time this week.

 

Like I said before, I did detect one source of drippage in the lower right corner of the rad, which doesn't of course mean that the hole/puncture is there but maybe somewhere higher and just draining its way to that dripping point. As for the thermostat/water pump, I will check whether there is a leak there when I get back to working on it, hopefully tonight, and will post updates.

Thanks for your reply.

 

Honestly, I doubt its head gasket, you will finally bust head gasket if you keep driving with a truck that overheats but not likely head gasket. It would take much longer to overheat and only after you blew most of the coolant.
just IMHO

 

Well, that sure is comforting. Thanks

 

I'd say that it's the thermostat that is stuck and not allowing the coolant to flow and exchange the heat through the radiator. Yes, you should refill the coolant by putting it straight into the radiator BUT ONLY IF IT IS COOL! Doing it hot can give you a terrible burn from the steam and the pressure could send the cap flying (that's why you have to press and turn it to remove the cap). The reservoir will suck coolant into the radiator as needed and allows for a place for fluid to go if the radiator is overfilled (when it's all working correctly). The "baby poop" oil and white smoke (steam) from the tailpipe would indicate that's it's too late and the head gasket is blown. If it's not there yet, don't keep driving it. Getting it too hot will warp the head and blow the gasket. It gets expensive after that.

 

How do I test if the thermostat is "stuck" ?

 

FYI, always look at Scotty Kilmer ANY time you have an issue. Most times you can fix it immediately with one of his videos.

 

Do you have access to grden hose with water ?
If yes...
Try that, Than idle the truck with hood open, once you see temperatures going up put hose with water spraying on radiator. It should keep it cool. If engine is still overheating despite full flowing garden hose on radiator than its Thermostat or water pump. (aka coolant is not circulating)

 

If the thermostat isn't built into the housing, you could pull it out and run the motor without it. If it doesn't overheat, that was the issue. It's behind the radiator hose attachment point on the engine.

 

It is built into housing, so he won't be able to do it, But Thermostat is right up there so its easy to remove and test in the boiling water pot (just don't let your wife see it, she will make you toss a pot and get new one in a fear of poisoning everybody.)

 

Ah, then yea. Take the whole housing out and sit it in really hot water. The bottom should extend out which opens it (to let the coolant through). If it doesn't open at least 8mm, replace it with a new one.

 

And just in case anyone wants or needs to know more about how thermostats work: http://auto.howstuffworks.com/question248.htm

 

So here is another question:

If the thermostat was stuck, not allowing for coolant flow between the rad and the engine, what was making the fluid boil in the resi tank?

 

The steam pressure in the radiator blowing bubbles down the tube that goes to the bottom of the reservoir. It's like blowing chocolate milk bubbles with a straw when you were a kid. It's not actually boiling the fluid but you hear the bubbles.

 

I take it that you have been down that road?

 

Thermostat has tiny bypass valve so once coolant boils in engine steam will go to radiator (top point for system) and from there through the cap to res tank, and bubble.
By pass is tiny so it won't cool engine but enough for steam to escape and not let engine explode like steam locomotive in 1860's

 

I am leaning towards the impeller being worn out and not moving enough water causing the thermostat to gum up.....

 

Yep this happens when you build pressure in a vessel and it can't escape to it finds a weak spot....

 

Not with Tacoma but with Honda. She did scream than toss a pot out and charged me for pot replacement.
It goes along side of
1. Opened carburetor which had gasoline on kitchen table.
2. She found Wheel bearings in frozen food section of fridge
3. She wondered what that big ring gear is doing in the oven cooking along side of burned gear oil.
etc etc

Behind every shady tree mechanic is his screaming very supportive wife.