abalagtas

....steam?

assuming a proper mix of toyota red?

superjoe83

way hotter than you want your engine to be at, probably 250-300, depends on the mix ratio and pressure cap

fiveofeen

212 F for water isnt it? anyhow depending on the mix and the pressure of your cap it will get up there.

Glenn

For one PSI increase above regular atmospheric pressure the cap is rated for, the boiling point is increased by 3° F.

The effects of the coolant vary by its concentration.

abalagtas

What if it is just bubbling in the overflow tank?

rudestar

cracked head or bad headgasket

Flamedx4

50/50 mix of ethylene glycol based automotive antifreeze/water is what is typically recommended. The figures below assume a radiatior cap mainting pressure of 11-15psi.

% antifreeze Freezing pt. Boiling pt.

33.3..............0*F.............. 256*F
40..............-12*F...............260*F
50..............-34*F...............265*F

Straight water, no pressure cap=
0 ................32*F ..............212*F

Agreed that it could be the head gasket, but could just be a faulty radiator cap. In fact, you *might* have just happened to look when some of the normal expansion was going into the tank.

youngbuck

The 212F is @ sea level though. The higher the elevation the lower the boiling point, but not by much. For example, at 5000 ft. elevation the boiling point may be 203F vs. 212F @ sea level.

Oh, and if you're getting overheating problems, a stuck thermostat could also be the culprit. And, make sure that you don't have any other coolants mixed with your Toyota coolant. Even a small amount can really throw things off and lower the boiling point considerably.

abalagtas

I pretty much know what caused it....

The dealer had messed up my FAL fan the last time they worked on the truck. Basically, they messed up the power lead and it would lose contact intermittently. The problem didn't show it self until months later. I already purchased a hayden fan controller and was going to install it. I had just gotten off the freeway and was on some side streets and noticed the temp rising, but not in the red. I pulled over immediately and popped the hood. I jiggle the power lead on the fan and the fan started. The coolant in the overflow tank was gurgling. I started the engine to get the coolant flowing through the engine and the temp went back to normal immediately. Dropped the hood and thought everything was ok. The engine was/is running great. I replaced the controller the next day. Today I noticed I have an oil leak on the passenger side under the exhaust manifold. Damn! I just did a valve job on this thing!

Glenn

Elevation above sea level matters only if boiling occurs in the open because it's related to atmospheric pressure. Since the cooling system is a "closed" system with radiator cap, the elevation above sea level shouldn't have an effect on the boiling temperature.

oly884

Actually, it should. The PSI rating is relative to the atmospheric pressure that you're at. A 15 PSI cap means that it will hold to 15 PSI above atmospheric pressure. So, at 5000ft, where the pressrue is lower, the 15 PSI cap will hold less total pressure than at sea level.

This is much like a pressure gauge. There's "gauge" pressure, and there's "absolute" pressure. Absolute pressure is the gauge pressure + atmospheric pressure. You could say that the cap rating is a gauge rating, not an absolute.

snap-on

I disagree

The cap pressure is determined by a spring. the K value of the spring doesnt change based on altitude. the pressure it takes to compress the spring (and create an opening for it to boil over) is constant (as K values are).

Theirfore I say its an absolute presure not a guage pressure.

oly884

but the force from the pressure on the outside of the cap will be less.

Atmospheric pressure at sea level, 14.7 PSI + 15 PSI gauge = 29.7 PSI total

atmospheric pressure at 5000 ft, 12.28 PSI + 15 PSI gauge = 27.28 PSI total

The water will boil at a slightly different temp. It's not JUST the force of the spring, but the force on the other side of the spring.

oly884

Meh, you're right, just read something that proves me wrong. Studying for finals has taxed my noggin a bit.

snap-on

abalagtas

So if the coolant was only 'gurgling' in the overflow tank...is that considered boiling?

Glenn

Do you see steam?

It's supposed to gurgle into the overflow tank as the coolant expands when it gets hot.

punkbek3886

however, if the ambient pressure was zero psi, do you think it would hold 29.7 psi of pressure? no, it would only hold 15 psi inside the radiator. if the ambient pressure is 14.7 psi, there is already 14.7 psi normally inside the radiator, making it possible for the cap rated at 15 psi to hold 29.7 psi. i think its rated for a 15 psi differential pressure, not an absolute 15 psi. i obviously agree that the k value does not change, but atmospheric pressure does exert force on the radiator cap.

superjoe83

next time it does this carefully grab the upper radiator hose and see if you can feel it boiling in the hose, you may want to wear gloves

Flamedx4

Not neccessarily. As the system builds pressure, the coolant expands. (Actually, as the coolant gets hot it expands - this is what causes the pressure.) At some point the radiator cap will "burp" some of the excess into the overflow tank. As it gets hotter it will burp more. Then later when the system cools the volume decreases and it sucks coolant from the overflow bottle back into the radiator - that's why the hose into the catch bottle goes almost to the bottom.

So unless it was just boiling out the tube, continuously and non stop, it was probably not overheating. No way to tell fer shur from a description, but from what you said that would be my guess.

As a side note, once in a while a younger guy who never had experience with cars before the EPA mandated overflow bottle systems were common would get an old car. They'd get frustrated because it was always losing coolant and they thought it had a problem, which they could not locate. In the old days, the first time you drive it after filling, the excess would overflow onto the ground! (gasp!!!) and next time you check it, it's "low." Fill it up, drive it, it's low.... AH the good old days... That's one of the reasons radiators used to be bigger than they are today.