Rambo

How do you get rid of air in the cooling system?

to make a long story short as possible,... Got a 93 mustang convertible from a police impound, took it apart, changed color, replaced all kinds of stuff,...finally got car on road. Took the car for its maiden test drive (after 14 months). Noticed the temp gauge never got above 130 the entire time driving...I was like..wtf. Bought a new sending unit, now, it jumps to like the second white notch from 270! So I figured I would change the thermostat to find out, there wasnt one. So I put in a 180 and tried it. Still same spot..way too high for my taste. Got another radiator since the one it had in was corroded around the cores I figured that was the prob. Well, apparently its another problem. STill running up second white notch from 270. So, whats left... Water pump, or the gauge is lying. Weird thing is, after the car is definitely up to temp from running, the top left hose is hot, but the bottom right hose is not hot at all. Plus, the system does not build pressure now. Could it be air in the system?

I'm not sure what the second white notch from the top is, but I'm thinking maybe 240 degrees? If I unplug the wire off the sending unit, the temp gauge drops to 0.

Im hoping its air in the system, how do I check and remove it, thanks.

ponyboy302

i think if you squeeze the upper rad hose it will push the air out

Mike W

My notch does the exact same thing. I have not changed anything yet except for the radiator cap which didn't correct the problem. I do notice my temp gauge will move up or down depending on if I'm in traffic or highway but does not overheat but comes close. My next step was a new water pump but have not had time to mess with it.

USMC1775

With the rad cap open, run the engine until the the t-stat opens, then squeeze the upper hose.

88_5.0

Make sure it's the proper sending unit.. For example if you use the factory sending unit with an aftermarket gauge it won't read correctly.

86HOGT

Find out what it's really running at before throwing parts at it.

Juanizzle

remove the cap, and raise the RPMs with the throttle cable, you should hear air escaping, also, you have air in your coolant lines, you should hear a nice gargling sound when you start it. lol

wowvfast

if it has the stock clutch fan check the clutch in it

mjr46

do you have heat??? turn the heater on, if there is air trapped in the cooling system , coolant will not circulate and heat output will be cold often or luke warm at that.

Rambo

Thanks for the replies,

I have a stock gauge, and sending unit.

The clutch fan had about a pound of dirt built up in the front of it, I blew all out, and it seems to have a fair amount of resistance.

I am getting heat, and the heater hoses going into the cowl are hotter then hell.

I noticed today, that the temp needle rises fast enough to where I can see it moving. I didnt get a chance to work on it today, crappy weather.

Usually, you can tell when the thermostat opens cause the needle would drop, but not in this case. Once it gets to its peak, it stays there. wouldnt the bottom hose be pretty hot also after the thermostat opened and the coolant was hot at the cap? The top hose gets pretty hot so the thermostat must be opening. Its almost like there is no water in the intake where the sending unit is, and its just getting hot air. Tomorrow, I will try to squeeze the air out of the hoses.

I could always go get a cheap aftermarket gauge and hook it up to see if its the stock gauge, but I think its something else.

Oh, would air in the system keep it from building pressure?