Mech temp guage wacking out still?

[Railing68]

After 500+ miles my mech guage still periodically flips out and shows huge temp spikes. To make sure it wasn't just the guage I switched 2-1/16 phantom out for an old pro-comp. The pro comp did the spiking as well, but it seemed to be less frequent and appeared to subside (only ran it for a couple of days). Since the smaller phantom fits in the console that is what I hooked up again.

I know the engine is not getting hot, so what is causing this, a steam pocket? I drilled 3 small holes in the thermostat and tried filling radiator last time with coolant while front end was raised. Could the guage really be the issue? My machinist swears he drilled the steam holes in my heads. I am probably going to call Autometer, but I figured they would lean towards steam etc. Any suggestions,ideas. Thanks, SS.

[porschev8]

It sounds like you still have air in the system. I had the same problem until I tried a tool called the "Mighty Vac". It's generally used for bleeding brakes and performing other diagnostic tests but I found that it works great for cooling systems. I connect it to the high point on my engine and pump the system down as I fill the system from the front fill point. My application is mid engine with the fill tank at the front of the vehicle and a bleed point at the rear of the vehicle above the motor.
You can purchase a Mighty Vac for about $60 at http://www.eastwoodcompany.com (http://www.eastwoodcompany.com/) item #46004
What kind of engine are you working on?

https://static1.pt-content.com/images/noimg.gif

[Railing68]

thanks for the reply, I didn't double post too my knowledge previously? anyway, I do have a vacutester it is just minus the tank, where are you connecting it to to draw out air and not fluid? understanding that your application is mid-engine are you using the overflow fitting, or? SS