Burp valve.....

No that's not something you use after chugging a beer and eating a hamburger....

I'm thinking that I would like to be able to relieve any air bubbles caught up in the system up by the radiator. My radiator has a top fitting and a bottom fitting (not sure which one is inlet and which is outlet) and I'd like to be able to "burp" out any air bubbles out of the top of the radiator. Instead of removing the radiator and and having a bung soldered in (which is a good way to go) I thought perhaps a quick and dirty way to achieve the same result would be to make up an in-line fitting out of soldered copper pipe with a burp valve install which I can place in-line of the top fitting in the hose.

Some other mid-engine "exotics" have a burp valve at the top of the radiator or in-line (lambo miura, f-car 308, etc.) and it seems to work well with getting the system free of bubbles and keeping temps down. Has anyone fitted such a valve? Does it help?

Thanks in advance.

The very best tool I ever bought was a vacuum cooling system filling device. Although the one I got came from Harbor Freight Tools, they no longer carry it. However, a similar device is made by UView:



Here is a link to the product description on the manufacturer's website:

UView: Product Detail

The way it works is totally ingenious. It uses standard shop air to blow across a venturi and create vacuum. In practice, you insert the tool in place of your radiator cap using one of the supplied adapters to get a good seal (I just use the cone adapter). You then open the valve and blow air across the venturi. This creates a vacuum and sucks all the air out of your cooling system. Close the valve, switch hoses, and now your new hose goes into a container of coolant/water. Open the valve again and the vacuum in the system sucks the fluid out of the container. As it does so, the vacuum level drops to zero and fluid stops transferring.

Close the valve, switch hoses again, repeat as necessary.

What used to take hours, and in fact days (since to do it halfway properly requires the system to be fully cooled down and then heated up again) can now be done in minutes. I've taken to traveling around to friend's houses with this brilliant little tool; in each case, their 'fully bled' cooling system had measurable amounts of air inside, which was easily dispatched with this tool. In fact, it's easy to fill a GT40 cooling system without having any bleeder anywhere in the system using such a device.

They are widely available, and the cheapest place I've found them is Amazon.com. Do a Google shopping search and you'll find dozens and dozens of retailers carrying them.

For under a hundred bucks, you simply can't beat it! :thumbsup:

Wow, that's a really neat idea Mike. Very nice. I can see how you're quite popular with your local car buddies (other than for just your charm alone).

I like it - should take out all the bubbles, not just the ones caught at the top of the rad. I'll buy one and give it a whirl.

Thanks!

Cliff you have a message...

You are on the right track with a fitting at the radiator Cliff.
I have a 1/8 bsp plug in the top of the out tank.
I remove the plug and put a barb fitting in when I am bleeding.
I attach a clear plastic hose a meter long to the barb and a peg to hold it vertical on the front clip.
When bled I put the plug back in.

The hose is to get the air out of the radiator without loosing your water.
Prior to this method I would have to stop start due to air pockets,now it bleeds without stop starting.

The other thing that I found handy is the purge from the rear of my heads I used a nylon translucent tube back to the tank(very tough stuff).
When the air bubbles stop coming up the tube it is bled,this takes about 20-30 min.

Jim

Mike you have a PM.

One of the tricks used on landrovers which are notorious for air locks is to fit a household radiator bleed valve. You can then bleed the air out hot or cold.

Any car that has an Audi or similar T/A that requires the 'nose down' engine installation is going to be air lock prone @ the rear of the cyl heads... small air bleeds that allow this to be continously purged to the header tank rather than 'forced' forward thru the radiator are a 'must have'.
Further to that if your driveway to the garage is 'downhill' & this is the 'last' bit of engine running the car has at the end of a long run a similar problem can occur regardless of engine angle & any small leak in the entire cooling system may allow air to be pulled back into the system while cooling down after shutdown..

I've handled it with an overflow tank and a pressure relief radiator cap. After I warm the car and a short drive, I'll pull the relief lever on the cap and you can hear the water (and bubbles) flow to the overflow tank. As the radiator cools, the vacuum draws the coolant back into the engine. Normally 2-3 "burps" will do it.

Veek
I like that bottle - looks the dogs - where did you get it from, the ones I have seen in the UK tend to be aluminium or motorcycle tanks.

The bottle was available at the local discount auto parts store. I wanted something I could easily check and it does the trick. When I bleed the system, I depressurize the radiator to the hot fill mark and that will do it. Note that I have the recovery tank feed coming off the stainless overflow tank. Here is link:
http://www.vetteweb.com/tech/vemp_0911_corvette_c3_project_vehicle/coolant_recovery_tank.html

thanks