"Burping" air from radiator

Could be right. At 65 MPH I'm running around 3000 RPM's. I think I'm gonna try the restrictor plate first and see if that helps me any. Thanks

 

I had a small block Ford do that to me. I had put the thermostat in backwards. Until the coolant on the rad side got hot it would'nt open. On my currant car (big block Chevy) it ran hot at high speeds only. Per the Hamb advice, I switched the vac advance from ported to full vac. That cured the problem completely. Thanks guys.

 

Okay-lets look at a different angle to your problem. 330hp 350 has Vortec heads no? If this engine has a Vortec style block there is no internal coolant by-pass provision-so heat spikes will occur as coolant can get trapped in the heads.
Plumb in a by pass(think big block chev) from the intake manifold to the suction side of the water pump-if you have a water pump with the plug in the top-pefect place to tap into or tee into the heater hose return port on the front of the water pump. Your coolant temp will stabilize.
First step-check to see if your block has a coolant by pass passage-there will be two holes on one side of the block where the water pump attaches.
If no by pass-you need to install one.

 

Valid point, now get ready for this. The set up on my 5Six is as you describe above. I have a rigid line from the top of my water pump (short style) to the intake. Now why did I do this? Because I have 1/8" spacer/gasket (alum that I fabricated myself) between my water pump and block and I purposely left out the by pass hole. I ran this way for a long time with no issue's until I needed to replace my water pump. After installing a new High Volume Water Pump, I began having the same issue's the OP is having.

 

The hole lets air pass before the thermostat opens, so with the cap off or the funnel on air is being bled off while cold. But your right I don't let the car go until I see coolant circulating. The funnel makes it the highest point for air to travel to, also makes it so you don't have to keep re filling the radiator as the air is worked out. Not all new tools are bad, especially if they're cheap, help you out and make it quicker.

 

How do you know it's spikeing at 240? Temp gauge COULD be off, use a n infrared to be sure.That's a new tool I think even Tommy would approve of.

 

I've been doing this for years, never had any slow warmup complaints.

 

Fill it with vacuum!

Yeah, it'll set you back a bill and a half. But... you will NEVER have to worry about burping again. Using compressed air, pull all the air out of your system then close the ball valve. This will double as a leak tester if the vacuum bleeds off. Hook the fill hose to the coupler, place the other end in the coolant, and let the vacuum pull the cooant into your system. It will find all the cavaties and be full the first time. Fill any cooling system in literally minutes.

I know it is the traditional way of doing it, but it sure is slick.

 

Hmmmm-
I would have to point at the pump-if the arrangement worked properly before the change-strange though..

 

Not trying to right, there are a lot of valid reason's that have been posted. I just find it interesting that so many of us use restrictor's (just realized I never stated before that I'm running restrictor now) instead of thermostat's.

 

To burp the Chevy 350 in my '23 T-bucket all I had to do was drive it on onto the ramp of my car trailer. That put the car nose up... with the cap off..

 

Lol, hopefully he's figured it out by now....

 

My radiator is lower the the top of the engine. I also drilled a a 1/8” hole in the blade or part of the thermostat that opens to bleed air. My thermostat housing is cast iron so I drilled and tapped it for a 1/4 NPT pet cock, drain cock, drain valve or whatever they are calling them nowadays. Jacked up front of car started engine and let it run then slowly opened valve letting air out until had solid stream of coolant/water. Let it cool down and did same procedure again. Also use a higher pressure radiator cap to keep coolant from boiling.

 

Boy howdy what the Fng dug up today to share his wisdom on.
My OT daily has three bleeder screws that work the same as the petcock that Pirate showed in post 74. Factory German stuff on an E39. You don't get the air out of it if you don't use it either. That setup works.