Radiator Overflow on my Towrig - Need Help

saf-t scissors said:
If either one of you can explain to me how a radiator cap that isn't designed to open until the coolant temp reaches 255F allows coolant to freely pass back and forth at 195F, I'll kindly STFU.

Until then.... :flipoff2:
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Ok then Here you go
Wel First I think you are getting the Radiator cap and the thermostat confused becuase the Radiator cap has a pressure rating not a temp rating.



Pressure builds up in the radiator and after the pressure gets to the rating of the Radiator cap then it opens and then and lets fluid into the over flow Bottle.

Now it shuts after the pressure is relieved. When the engine starts to cool down it creats a suction and opens the little valve in the center of the cap and sucks the fluid back in. see picture #2. When presure is higher in the radiator the little valve is press Shut againest the rubber seal.see pic #1

So There you have IT :flipoff2:


therm001.jpg


therm002.jpg


No Radiator Caps wer harmed in the creation of this post
 
So, It needed a radiator cap that let the colant out at 195 instead of 255?
 
Ridgerunner: A picture is worth a thousand words! Thanks

Wolfpack Offroad: Thanks for "edumacating" me

Above all I am happy to hear he has found the problem.
 
Ridgerunner said:
:confused: radiator caps do not have temp ratings!!!!!!!
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While thats true, what I meant is that it would not hold pressure enough to get the coolant temp to 255 before releasing. (Pressure increase = temp increse.)
 
cap

Chip was correct in his description of how the cap works. The cap is rated at 7-14 lbs normally, and dosen't care what the temp is. When pressure reaches the rating of the cap it will release into the overflow. As the system cools, it will pull fluid from the overflow tank back into the radiator.
 
I guess one thing we have all maybe misunderstood. All my manuals refer to the little jug thing as a "reservoir" not, an overflow. which in it's self, would indicate it will be used as coolant again. As my son used to ask me(when assembling something) "did you read the clues dad?"
 
all the arguing over radiator caps aside, my first two hunches would be either a t-stat blockage (or other area of cooling system blockage) or head gasket. your coolant temp guage is a poor indication of actualy engine/coolant temp. if the sending unit is reading an air pocket, non flowing coolant, etc. it will give the guage a false reading. i've personally witnessed numerous vehicles that will show a normal temp on the guage, but in actuality have a reading of 250+ at the radiator. in most systems, the sending unit is about the last thing to see the coolant after it circulates through the block/head.

as for a head gasket, it is possible (though somewhat rare) that you will get exhaust gasses pressurerizing the cooling system without oil contamination or visible steam from the tailpipe. this is a fairly easy check though... just take it to a shop that does inspections, and have them stick their tailpipe sniffer just above the coolant in the radiator neck/fill hole. they can set the computer on a "realtime" or manual mode to pick up CO readings without doing an actual inspection. if you need somewhere to do this, drop me a pm... i know a couple of people at the dealership i worked at that are familiar with the procedure.
 
if you suspect a blown head gasket, you can try a trick that we do at work. if you can get your hands on a 2nd rad cap, drill a hole in it and put a male nipple from an air chuck quick release in it and use epoxy/jb weld to seal it up. remove your spark plugs and screw this cap on your radiator and pressurize the system with about 10psi and leave it over night. next day, place a peice of white cardboard or paper over each of the open spark plug holes. spin the motor over about 10 times with the plugs still out. remove and examine each peice of paper or cardboard and look for droplets of coolant. this will also tell you exactly where the head gasket blew if it actually did. heres how it works; the pressure in the system will force coolant that is in the block up agianst the head gasket and through any hairline cracks or fractures. pressurizing it over night will help maintain the pressure that may be lost through other leaks in your system. it is also a good idea to watch it after you pressurize for a few minutes to see if you have any visible leaks. this method also works well for finding pesky radiator leaks. hope that helps
metty
 
Ok so Here was the problem the Radiator that was in Kens truck. IT had 2 hose connections near the radiator cap one was at the cap and one was just below the cap. the one at the cap was supose to go tot the over flow and the other one back to the engine. These were switched.

And now It is Fixed!
 
rattlecanpaint said:
While thats true, what I meant is that it would not hold pressure enough to get the coolant temp to 255 before releasing. (Pressure increase = temp increse.)
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While this is True that as the temp increases so does the pressure but the pressure is determined buy the expansion of the coolant which is also related to the boiling point.



For Example Straight water will boil at a lower temp than 100% antifreeze will.

If you had a radiator full of straight water and no Cap it would boil at 212 degrees the pressure of the cap will allow it to go to a higher temp before it boils. With the addition of anti freeze the boiling point is reduced. You never want get to the point of the engine coolant boiling, because then you loose you’re cooling properties.



If the water boils no matter what the temp is the pressure will build and the cap will open.
 
Ridgerunner said:
Ok so Here was the problem the Radiator that was in Kens truck. IT had 2 hose connections near the radiator cap one was at the cap and one was just below the cap. the one at the cap was supose to go tot the over flow and the other one back to the engine. These were switched.

And now It is Fixed!
Click to expand...


Yup this is correct..

this is exactly what happened. and whil efixing that I also notice other leaks, seem to other hoses for tranny where loose.. so they whole thing was leaking :(


ALL FIXED NOW
 
wow...it's the simple things huh? Your truck just wanted some TLC... ;)
 
BIGWOODY said:
and everyone now knows how a radiator cap works...
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In excruciating detail! :D
 
Not at all.. I just would NEVER have guessed we could take 2 pages explaining a radiator cap... It's kinda funny, don'tcha think?

That reminds me.. the cruzah needs a new one..
 
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