school me on cooling systems

Reply Subscribe

Thread Tools

Search this Thread

Nov 11, 2016 | 07:39 AM

RJL1

Thread Starter

Senior User

Joined: Oct 2016

Posts: 105

Likes: 0

school me on cooling systems

Last weekend I dumped the coolant and put in a new thermostat and upper radiator hose. When it warms up as I drive the temp gauge goes all the way up to 3/4 hot and then I guess the thermostat opens up and it runs at right about 1/2. It sits and idles at half, drives at half, doesn't move. Normal? I can't see the radiator being clogged because it runs at half when it's warmed up and stays there. I'm not sure which thermostat I have, just took the one from NAPA and didn't think to ask what temp I have until now. Should I have the radiator professionally flushed? I'm not a mechanic, just a parts changer.

Thanks

Bob

Nov 11, 2016 | 11:14 AM

Lead Head

Lead Driver

Joined: Jul 2007

Posts: 7,868

Likes: 9

From: Rhode Island

It shouldn't jump up then settle down. You may still have air trapped in the system.

Nov 11, 2016 | 12:45 PM

BruteFord

Postmaster

Joined: Mar 2013

Posts: 3,066

Likes: 7

From: Over There

Yeah, you just had an air bubble under the thermostat that was preventing it from opening. Not uncommon, easily solved, and likely all better now. If it continues then maybe reconsider.

FYI for future reference, whenever I install a new thermostat if it doesn't already have one I drill a small hole in the metal around the valve. The smallest drill bit I haven't yet broken, just enough for some air to pass thru. This prevents air bubbles from collecting under the thermostat without allowing much coolant to bypass the thermostat.

EDIT..
Also putting the upper radiator hose on the water neck is the next to last thing I do. I fill the radiator/cooling system until water comes out the water neck, then put the hose on. This let's me be sure that the thermostat is submerged in coolant.