Another automatic radiator air bleeder

So, I finally got some time to check the radiator bleed screw (328 GTS '86). It is an M6, about 10mm long thread.

All I need now is an adapter from BSP 1/8 or 1/4 to M6. The BSP system 1/8 = 9.7mm and 1/4 = 13.2mm.

 

I did this on my 82 on both the radiator and the thermostat housing. I took the SAE version supplied by Alladin and with a tap and die set modified the Alladin vents to go into the orignal holes of the t stat housing and the radiator. No need to modify the car. Just cut down the vent threads to fit.

Also of note, the radiator is soft.....and so is the t stat housing hole.....so be gentle when installing or you will strip the original threads of the holes. Use teflon tape on the threads to seal.

 

I have always wondered the same thing about rebuilding your a/c system tip-top then filling it with that horse **** R134. Makes ZERO sense in a R12 system. NONE.

It would be like building the best, money-no-object 1/4 mile dragster possible then using pump gas because it's cheaper.

 

I will explain why for me. A few thoughts....

It doesn't replace doing the other items....hoses, t stat, expansion tank, service the radiator, fans. That is a poor assumption you guys are making that this is done to surplant any other maintenance without any consideration of the cars. Actually a little surprised you guys did that. On my car I have replaced my expansion tank, t stat, and hoses with new. My radiator and fans are original and fine.

I see it as cheap insurance and convenience. New parts can fail just like old parts. Last thing I want is the possibility of a bubble around those sodium filled valves no matter the cause. I believe that is where the snapped valves begin in the cars.

Many new cars are already self bleeding. This isn't new stuff.

Its fully 100% reversible without any modification to the t stat housing or the radiator, and they work.

Why wouldn't you want it? What is the down side?

So are those adding more cooling capacity via a larger core copper radiator or an aluminum radiator, better fans, or those adding overflow bottles to their cooling systems any different? Are they masking some issue? The car does have its deficencies in the cooling system when compared to what we can do now.

In my mind, the removal of the possibility of a hot valve because of an air pocket in the head is what I like and the fact its fully reversible.

I can say my cooling system is perfect now. Never over 195 even in traffic, 175 or so on the highway, no coolant out the expansion tank, no drama at all. This with the stock radiator and fans.

 

Those bleeders let air out, but do we know for sure that they wont also let air in as the collant contracts?

 

Like any other bleed screw, if it is sealed properly, it shouldn't. Don't forget, you have the expansion tank in the system, so any contraction of the coolant should draw fluid from the expansion tank rather than air around the bleeder. I would think if it is sealed well enough that fluid doesn't leak out under pressure, it won't allow air in during cooling.

 

I wasnt thinking about air keaking around it but rather through whatever mechanism that lets air out.

 

I have used two of these self bleed valves and am happy with them. What I did notice is that if you are, say, changing a T-stat, then the valves didnt seem to bleed out the large volume of excess air quickly. There was a tremendous amount of air in the system that was playing havoc with the tstat operation - temps sailing right up then falling, then climbing again.

So the old advice of bleed and bleed again may still apply.

What was easy though was taking off the top of the self bleed valve and just depressing the small ball bearing that seals the valve with something pointy. That allowed the air to vent much faster. I ran the engine from cold and as it heated went back and forth between the rad and the t-stat housing bleeding air off until water appeared. It took quite some time!

Drove it and repeated it. Heaters on, find some driveways with angle to move the air out of nooks and crannies. Bleed again, top up glycol in the header tank to replace the vented air.

I think the bleed valves will now continually strip out small amounts of air remaining.

The other oft repeated advice is to make sure there was a) an air bleed whole int he Tstat (drill if there isnt) and b) that the hole was oriented to the top of the housing, so that the air can find its way to the very top of the housing to get bled off.

I replaced the tstat with a 180f vw golf/rabbit 1.6 from Autozone at $9.99. Working perfectly.

 

Are the self air bleeders still available? I tried going to the website but tells me the site is no longer. If so do you have the website information? I have to bleed my car quite often.
Thanks Dave

 

Hi Dave,

These are common in the UK, so Google is your friend in finding one. Note that they are designed to be used in central heating systems there where hot water from a boiler is circulated through a number of radiators. Each radiator needs to be purged of any air and these bleeders are used to replace the traditional plugs that (like our 308 radiator plugs) are manually operated as needed.

The fact that you need to bleed your radiator often indicates an issue you may want to look into. Have a read of the various threads on the topic and especially one that is currently in discussion that talks about coolant level, bleeding your system, etc.

Best,

John.

 

I drive my car 2 to 3 times a week. Once a week or so I get a little air out of it. I can tell when it needs to be bleed by the temp needle will jump back and forth. I have read a lot on this subject. Checked all my hose clamps for tightness, did a block test checking for exhaust gases in the cooling system, come back negative both times. I did have to replace the long heater hose from back to front not long ago, maybe still some trapped air??? Open to any more suggestions. It is a 85 308qv euro. I have almost every nick pick thing working and back to original as possible. Thanks Guys Dave

 

Im looking for a cleaner and easier way to bleed to tstat housing. When bleeding i'd like to be able to open the valve and have any overflow caught and for that you need a hose fitting.

The tstat bleed valve is an m8 thread which is hard to find fittings for. I hate how the oem valve spits fluid out and is a lot of leaning over mopping hot fluid on a long bleed as the system burps (i find a lot more burps when revved)

Would this brake bleeder work? I cant see why it shouldn't, being all metal able to withstand brake fluid it should be able to handle coolant. You can run tubing into a temporary catch container, no mess no fuss. My main concern is that it goes too deep into the housing and interders with the tstat itself.


https://www.summitracing.com/parts/rus-639520/overview/

Any thoughts?

Alternative any source for 8mm pipe fittings appreciated.
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No, that would require a seat to seal against

 

Thanks Patrick, appreciated. Robert, thank you and that's what I was originally thinking but couldn't find right fittings. Will report back.