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Coolant Burping and Thermostast Temp.

1675 Views 8 Replies 5 Participants Last post by  82MKIILtype
K ... seriously ... If i have to take the thermostate housing off one more time ... I'm going to buy a Honda! I'm that fead up. (see Lessons learned in General Chat for history if you care.)


82 Supra runs at just past verticial on temp gauge but occaisionally jumps drasticially ... sometimes comes down ... other times not. I figured it was air traped in the head and burped and burped and burped it. Nothing. No air bubbles at all. At one point I had it on a hill with a jack under it so that the nose of the car was so high that the rear bumper was on the ground. Still no air bubbles ...

I have identified a tiny leak at the thermostat housing hose clamp and fixed it so that is probably where the bubbles of air were comming from. It was about -5C or 22F here today and after I started the car within 5 min. the thing overheated. I felt the top rad hose and it was ice cold. The thermostate never opened ... I figured that air trapped in the head wasn't transfering enough heat to the thermostate to open it and therefore boiled the coolant trapped in the head. I deceided to remove the thermostate, cut out that little air bleeder valve thingy. and drill it out to about a quater inch diameter to help get the air out and to let "some" coolant flow even when the engine is cold.


Holly Crap! Filling the rad on a level surface I hear a steady stream of bubbles for about 15 sec. and the car sits and idles all freaking day long without a problem. This where it gets interesting ... 'cause now the gauge is a bit before it reaches verticial. (not a big surprise)


-How cold is too cold to run the 5M-GE all the time? (I am going into a Canadian Winter)

-Affects on performance, durability, pinging ect. of a cool engine?

-If I choose to get ANOTHER thermostate and snip off the air bubble thingy and NOT drill to make the system run closer to normal 188 F WILL THE STUPID THING BLEED OUT THE AIR.

I'm kind of looking for experience not theory here and I have access to a thermal gun to accuratly read the engine temp so I'll post the real temp reading soon. Oh yeah, new Toyota theromstate, cap, rad ect in system.

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I stuck one of those plastic tees, with the threaded cap in in the upper heater hose. Between the head and the heater valve.

I fill from there to help fill the top of the engine. I leave the cap off to let the air bleed out when I first fire it up.
Did I say I wasn't looking for theory? Errrrr Ummmm maybe now I'll take it. Am I the only person in a cold climate to have these kind of problems bleeding??? :confused:
No, I'm sure you're not the only one. The Toyota cooling system has always been a little harder than others to get the air out. I would suggest that the little jiggle valve be pointing upwards when you put the thermostat back in. You can cut it off if you like, it's just there to give more backpressure to the system so it forces the bubbles out faster, but I seriously doubt that you'll have any ill effects of not having that there.
It seems you've done everything right on burping your vehicle properly, including raising the frontend to get every bit of air out, Maybe let the vehicle sit overnight in your driveway with the front on blocks?
The only other thing I can think of is did you turn your heater on full heat when you burped the system initially? I'm sure you did, but thought I'd ask anyway.
To tell if its opening up properly, for a 185º F thermostat, open up the rad. cap on a cold engine, and put the probe of a meat thermometer in the water. Start the car and wait for a while, it should read cold right up to the point of the thermo opening, at which it should be around 200~210º F. You should see the water flowing inside of the radiator until it hits about 185º F. The whole process should start again, but much sooner.
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yea sounds to me that u just have an f'd up thermostat. just take out the thermostat, put it in sum hot as hell water and see if it opens up. remember it opens up by wax so if the wax was super cold then got super hot, it prolly cracked and went bye bye, u might take it out and see no wax at all? but yea, if thats the case, u might need to get...a higher temperature thermostat? unless ur part of canada isnt cold 24/7. i live in cali where its always hot so i get low temp thermos and my car runs cooooooolll 8)
O.K. Just got the temp checked and it's running at 146 deg. F I think thats a bit chilly but what do you guys think about the effect this could have on the engine???
This may be theory, sorry, but if you run the engine cold, the fuel injection will run richer. This can cause gas dilution in the oil, you theoretically will not get the engine temp hot enough to boil off the water vapor also. Modern engines are designed to run hot for fuel efficiency and emission control.
If your engine does not run at the proper temp. The engine life will also be shorten. The hotter your engine runs. The less wear on it. If you take the thermostat completely out. Engine life can be cut in half or even more. It's never a good idea to remove the thermostat. Make sure your engine is running at the factory designed temp. A $5 thermostat can kill a new engine very fast.
Yeah, I thought the low temp might make the cylinders and other clearances a bit tight. I still think I'm going to cut out the little check valve out of the new thermostate to make sure there is still enough coolant circulating when cold to get rid of air bubbles and "prime the thermostate". I won't drill it out this time ... I figure that should put the temp somewhere about 175 deg. F What does everyone think about running at that temp?

:banghead:I can't believe I'm going to take off the thermostate housing again...:banghead:

I think somebody needs to make an Emotiocon where a house just falls out of the sky on a happyface and crushes him like on the Wizard of Oz. (Gotta have the legs twitch) Put the little s.o.b. out of his misery.
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