Top hose hot , bottom cold...new radiator

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mbaird

mbaird

mbaird
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So I noticed that my top hose is getting hot but my bottom hose is luke warm. This did not bother me until I noticed a drip from somewhere.
The top hose seems to have a lot more pressure than the bottom as well!

The only thing that is not new is the thermostat. Champion aluminum radiator , all new hoses and ENGINE. Could it be an air bubble ? Or a bad stat ? Or a defective radiator..?

I know thermostats are cheap but I want some ideas before throwing time and money at it....
 
The difference in hose temps shows the rad is doing it's job,, getting rid of heat,, and pressure is equal throughout the system..

It would be wise to put in a new thermostat.. ask for one that "fails open" to prevent an overheat if it fails..

hope it helps
 
Well is the engine running hot? What is the temp? Your top hose should be hotter than the bottom as the water flows in thru the bottom and out thru the top.
 
I understand the lower will be cooler due to the radiator doing it's job but the pressure should be equalized I would think.!
 
The lower rad hose is the suction side of the pump,, but the pressure in the system is whatever the radcap is rated,,

SGBARRACUDA said:
Well is the engine running hot? What is the temp? Your top hose should be hotter than the bottom as the water flows in thru the bottom and out thru the top.
Click to expand...

mbaird said:
Dont you have that backwards?
Click to expand...

yes, he does..

hope it helps
 
What did I say wrong? Water is picked up from the bottom of the radiator and out the top hose back to the radiator!
 
If you have an original old-school brass & steel radiator I'd recommend getting a lower pressure rad. cap like a 10-lb... the ones you typically find at parts stores are 16-lb and can cause leaks on our 40-year-old stuff lol. NAPA is the place to go btw the other stores don't have much of a selection...
 
Um............. Wait.......... The top hose is hot and the bottom is cool right? That means the radiator is working..........:banghead:
 
After rereading I see what you meant about flow direction. Which leads me to think about lower hose possibly collapsing. Which in turn would create pressure on top but not boottom.

I will put new thermostat in ... But kinda want to minimize time chasing issue.

I would assume there would be no pressure difference if Tstat wasn't opening.

Couldn't see where small drip was coming from. Fan may have evaporated it too
Quickly.

I have also been chasing a huge P/S leak... Put new pump on and still have big puddle....
I suspect the cap.... But double gasketed it and still a puddle ? Might have to take the fan off and run for a few minutes to trace leak sources... Wait a minute , is a leak a food ? Or is a leek a food ? Lol
 
With your engine running at normal temp, idling, the pressure will be the same throughout the system. Now if you were to rev it up, you will see a drop in pressure in the bottom hose as the impeller drops the atmospheric pressure( below the normal 14.7 psi at sea level, less at elevations). But that would be temporary.
 
You are pulling cooled coolant from the bottom so the bottom will be cooler and have less pressure.

If your temps are fine, chasing the issue is pointless because you don't have an issue to chase.
 
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