"Burping" air from radiator

Yeah it goes back up but it runs at 180 a lot longer than it does when it goes up. Dana brought up something that actually I should have thought of...the bottom radiator hose. It doesn't have spring and the fit isn't the greatest. I will def check that out. I did drill an 1/8" hole in the thermostat but that didn't help.

 

Fill the radiator and leave the cap loose,let the car idle,wait for the fans to cycle twice.Then shut off and refill radiator.If that does not help you might want to look for other problems.

Steve

 

Check the hose and almost sound like a sticking thermostat if hose checks out try removing thermostat and put in a restricter and see how it does I have had lots of problems with new stats for some resone or other may take 3 to 5 to get a good one and I always put them in a pot of boiling water with a temp gauge to check them be for I install them.

 

do the nose up truck also squeeze the radiator hoses like your trying to squeeze them shut... we did this on my brothers mustang. worked like a charm

 

"As far as airflow the only thing I've been told to try is put a couple of 1/2" holes in the shroud to make sure that the shape of the shroud isn't creating a turbulence not allowing sufficient airflow. Have you heard of anyone doing this? "

Cooling Componants Inc used to put two rubber flaps in their shrouds [all three of mine have them], but I noticed the new ones no longer have them. I was told they were there to allow built up air to escape.

 

Any chance it has a reverse rotation water pump when it shouldn't have?

My 250 would spike like this till I change out the t-stat. The old one work great after the first time it spiked. I wouldn't think yours would be opening and closing like that, most of the time they stick either open or close.

Lower hose is a good place to look, heat can really soften them up and flow can suck them closed pretty fast.

Joe

 

That's a Fact...I do it on every thermostat I install. Some of the later thermostats have a by pass hole from the factory for this reason. The cooling system his burped of air before you crank it. Simple but very effective

 

Drill a 1/8" hole in the flat part of one of your old thermostats and reinstall it.

someone with experience ! finally a glimmer oh hope here ! always drill a hole if not there !

 

^this

 

Plus one.

Unless you have a SBC/etc, mounted in the rear with some goofy long hoses...never need to "burp" one.



Sure, someone gonna chime in and say they always had to"burp" their '66 Chevy after a radiator flush...I'd say they just had to add coolant after the T-stat opened

 

Use a high volume thermostat or drill a hole.

 

Wedging an aspirin in the thermostat will usually hold it open long enough to purge the air.

 

I once had to remove the top radiator hose and force water into the motor with a garden hose to get one to calm down. Then reattached hose, fired it up and just kept filling the radiator... took 20 minutes but finally got it to burp.

Another way would be to pull the thermostat and fill it up while running for a short while. When it gets warm, shut it off, cool it down, put the thermostat back in and all you have to do is fill from the water neck up in the radiator.

Worked for me a couple of times.

 

i think everybody is overthinking this.unlessit climbs to about 250 and stays there there is really nothing to worry about. all of us old guys (iam 65) are stuck on 180. in the late 70s and80s they boosted the temps for smog control. look at your newe daily drivers they all run at 210-220. if you are concerned try different relay on fan that comes in earlier tom

 

if you feel it has an air bubble trapped, go to your local GM dealer, we have a tool called a 'vac-n-fill', it pulls a vac. on the cooling system, then it sucks the coolant in. this thing works great. I used to do the nose high trick, and the funnel trick, but the vac-n-fill takes 5 minutes and works flawlessly for removing air.

 

It does work great. You don't have to go to a dealer though. Very common tool. I have a small shop and have used one for years. Most tool places sell them. Even napa does though it might be a little more expensive. Stop by and you can borrow mine


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A goofy trick I saw in an old Popular Mechanics magazine- remove the top hose and drill a 1/8" hole in the outlet neck of the radiator at the top, about 3/4" from the end. Put the hose back on, but don't push it on all the way, leave the hole exposed. Fill the system, and the air will escape out of the bleed hole you have drilled. When you get just water coming out, push the hose home, do up the clamp and your'e done.
I have never had to try it, but in theory it should work.

 

You don't by chance have your temp sending unit in one of the heads do you?
I made that mistake once and got exactly the same results you are getting. Moved it up to the manifold and all was good. Just a thought.....

 

Go get a Lisle #24610 funnell gizmo. You hook it into the radiator cap and add fluid in it then let the motor idle for a while, the trapped air will purge and be replaced by fluid. It has an internal plug so's you can take it off with the engine running and reinstall the radiator cap before shutting the engine off.
Very slick gizmo. One of them 'must-have' tools.

 

When doing my initial system fill I'll back out a fitting on the manifold such as a heater hose bung or water sending unit/plug. Fill till it reaches that point reinstall plug and top off the radiator. Bring it up to temperature then add coolant accordingly.

 

Fords factory advice back in 79 was to put the thermostat in hot water to open it and put a piece of hard candy in it to hold it open. That only works one time until the candy dissolves. I just drilled a hole.

GM usually used the hole in the head for an overheat temp sender. The head will get hotter when the thermostat is closed.

 

Great, mine did the same thing last week. I drove it longer that before ,temp 180 for about 15 miles, shot to 240 cut it off and started up, right back to 180. I knew it was not running hot but it scared me. This was the first Interstate driving. Was told it was an air bubble. Thanks for the advice.

 

Here's the Lisle #24610 gizmo... I've had a similar set for many years ... just the ticket for filling/air-purging a radiator..

 

I also was told that the old style radiator cap would not release the air as well as the late model cap. I was told that the cap with the wings was old and the round cap was late.

 

How the hell did we ever get by without these new must have tools?

 

Funny you say that. I barely use the new tools. My employee uses it all the time. I find its usually just as easy to do it the old way.


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That's it, I ALWAYS drill a small hole in the thermostat and use my funnel to fill. I use the funnel on ALL cars I work on, import and domestic. Some cars come with a bleeder screw because they are such a pain the get all the trapped air out, but the funnel works on those ones too.

 

x 2

 

There may be some modern cars that require some fancy tools but I don't want any of them. The split second that the thermostat opens any drilled hole is useless. I never install the radiator cap until the engine is up to temp and I can see the coolant circulating in the radiator. to me it's one of those internet myths that the young guys read about and keep repeating it cause the guy on the internet say so... Bonjour.

 

Streetrodder13, you stated new water pump. All these replies I posted above are what I'm leaning towards as well. I've had High Volume Water Pump's that have pushed thermostats shut at higher rpm's. This may be your issue and not trapped air.