Topic: Water pump, Thermostat or setup

[pacman454]

Thought I would post this question on here and see what you guys think.  Getting a few miles on my rat now and have noticed the temp will cycle up and down. Most of the time it is moving up and down but will stay steady at 190 once in a while.  It will slowly (5 min) rise to roughly 230 and then drop quickly to 190.  First thing I did was replace the thermostat with a better one, and still does it.  Drilled a small hole in side of the thermostat, thought maybe had some air trapped in there.  Still does it. Have a new alum radiator in a Model A frame so the rad cap is in the center. Was looking at the elevations and the radiator cap was just slightly above the thermostat.  Tried raising the radiator and bit and tilted a little more vertical, in case air is getting trapped. Rad cap is now about  2" above the thermostat. Still no results.  Water pump is also fairly new, but is a no-name brand.  Also have an electric fan on the radiator, runs all the time.  Driving or idling doesn't seem to matter.

[hotwheels]

Which side of the radiator is the fan on? Is your fan set up to be a pusher or a puller? I had a similar problem and found that i had my fan set up to pull, when it should have been pushing......

[pacman454]

The fan is set up as a puller.  It is between the radiator and the engine.  Had it wired backwards to begin with but corrected it. 

[obama]

What temp thermostat is my first question, then check for more air trapped, pull cap run up to where the water is flowing ( open thermostat) and fill as you can.   You mentioned water pump, does it have any wiggle to it when you grip the fan with your hands? don't do this  test while the motor is running unless your really fast.

[pacman454]

Thermostat is a 190 degree.   I did try adding some coolant with the cap off once, when the thermostat opened coolant started overflow the filler neck, landed on the water pump and got me all wet.  I will drain a little bit and try again.  I know some air gets trapped in the upper rad hose.  I can "burp"  it by squeezing the hose.

[pacman454]

Sorry, I think I deleted someone's comment. My sausage fingers are too big for the I-phone.  I swear that thing just does the exact opposite of what I am trying to do.

[miraclepieco]

For filling while running with the cap off, get a "Spill-Free Funnel." Big funnel that fits in the radiator neck and can handle lots of expansion. All the pros use them.

Just read a post where a guy swears by "Water Wetter." Said he couldn't drive his rod without it - lowers temps by 15-20 degrees.

[pacman454]

Bought the Spill Free Funnel and replaced the water pump, and it worked like a charm.  Jacked up the front of the truck and burped the upper rad hose with the funnel attached and got a lot of air out of it.  Probably didn't need to replace the pump, but I just trust it. I could tell water wasn't circulating all the time, the lower rad hose was much cooler then the top.  Thanks for the help.

[obama]

Glad it woking.

[hotwheels]

Glad you got it. Replacing the water pump is probably a decent investment, never know when they will fail and leave you stranded.