barachie

I recently purchased a 95 3.0 4Runner, in good working order albeit with weak cabin heat. The previous owner believed it was due to a clogged heater core. I drove it 60 miles home with no issues.

I decided to replace all fluids (oil, etc.), including a coolant flush. I figured id replace the thermostat as well, considering its a cheap part. In doing so, however, I first mistakenly removed the 90 degree metal elbow connecting the upper radiator hose to the engine block cooling system. No big deal, or so I thought...

I used Permatex FormAGasket number 1 to reseal the elbow. It has leaked twice now, which correlated with the engine overheating (I now know to use rtv silicone).

The engine overheats now, getting just below redline while idling after five minutes.

My question is this: could the leak be causing the overheating? Note: it was just a small leak, steaming out. It wasnt gushing, and I imagine the coolant level was still in the acceptable range. I would be surprised if losing that small of an amount of coolant would cause it to redline.

Thanks.

DallasTX

I agree, the very small leak you described would not cause it to overheat.
Is the thermostat the right one (correct temp rating) and installed the correct way...pointng the right way and with the jiggler at 12:00 o'clock?
3.0s seem to have a way of trapping air in the system. Make sure you 'burp" it to get all of the air out. http://toyotarepair3.blogspot.com/20...nt-system.html

barachie

The tstat didnt have a jiggler.

If something called a 'jiggler' is the source of my problems, well, that would be a first!

Ill let you know how it goes today.

DallasTX

Toyota t-stats have them....not sure what the technical name is, but is jiggles. Most likely culprit since you just changed fluids is air in system

barachie

Oh yeah, I noticed that the original tstat had that, but not the aftermarket one I purchased.

Curious, whats the jiggler's purpose? Im sure it's been answered already somewhere on the forums, but Im taking off the running boards right now.

DallasTX

I am sure there is a lot of debate and opinions on if they work and if it matters if it is at 12:00 or 6:00 o'clock, but they are suppose to help remove trapped air.

http://www.stant.com/index.php/engli...rmostats/faqs/

What does a jiggle pin do?
It helps bleed the cooling system of trapped air by allowing air to pass into the radiator and released from the system.

My thermostat has a jiggle pin but the Stant thermostat doesn't. Will a Stant thermostat still work?
Yes. Many thermostats have a “jiggle pin” that allows trapped air in the cooling system to pass through the thermostat and be released from the system. Some Stant thermostat do not use have a jiggle pin. These thermostats will have a "bleed notch” or other method of removing air from the system.

barachie

Success! DallasTX you were right; air in the system. Moral of the story: make sure to bleed after you change your coolant!

DallasTX

Cool. Glad you were able to resolve it.