Q: re: Automatic Bleeder Valves

Pointless if you keep level in the exp tank. Ok till they stick open and dump your coolant.

 

There's quite a few people here using them with good success. I tried them on the radiator and thermostat, and they did auto-bleed well. However, after 2 or 3 years the unit I had on the thermostat came apart and began leaking a bit of coolant on one drive. I haven't read of anyone else having that issue, so it might be a one-off.

I re-installed the drilled bleed bolt on the thermostat, and have a petcock valve on the radiator now, so I am back to manual bleeding a few times after a coolant change.

Cheers,
Gordon

 

Thats what scares me.

 

From my understanding they contain a hydroscopic agent that expands and seals the vent orifice when coolant makes contact. In my experience they don't work. Once they get wet and seal they never dry out and open up again. Plus they are horrendously over priced.

 

If you keep your system leak free no need for any additional gadgets,Ferrari design works just fine

 

As has often been said, when these cars were new, the owners didn't have to take them to the dealer every few months (or weeks) to have the air bled from the system. The cooling system does not manufacture air so if recurrent bleeding is necessary, there is a leak. Fixing the leak will eliminate the need for any bleeding or aftermarket "fixes" that obscure the actual problem.

 

If it ain't broke, don't fix it. I have had zero issues with trapped air in 3#8s. One client had that on his radiator and told me not to worry, it may dribble a little. Okay, sounds great. He liked it. Even with a dribble.

 

Bad experiences here also, avoid them. Use the solo cup with a hole close to the top hung over the bleeder on the front and the drilled bleeder screw on the rear. Automatic??? NOPE! Sorry Clark and Clark. I had one in the front and one in the rear with an adapter, neither really worked and both failed within a year. left me stranded.

 

I’ve been using the auto bleeder with success until recently. Since my last coolant flush, it’s not working. The auto bleeder never leaked, but just isn’t doing what it’s supposed to.

I can also confirm, no leaks to the system. I’ve pulled a vacuum using the Airlift system and the car holds vacuum. It’s been a recurring ***** for years.
My auto bleeder brand was called Aladdin I think and was only used on the radiator.

 

"I can also confirm, no leaks to the system. I’ve pulled a vacuum using the Airlift system and the car holds vacuum. It’s been a recurring ***** for years."

Are you saying that you get air in the system that you have to bleed regularly despite pulling a cooling system vacuum that holds OK?

The ONLY way air can get into the cooling system by being pulled in (or PUSHED in) via a faulty fitting/gasket/clamp, etc. Have you done any checks for head gasket leakage? Are you using the correct radiator cap - the one with the little valve spring-loaded closed as opposed to hanging open?

Again, these cars didn't have to be re-bled periodically when they were new. If they do now, something has "failed." Could be as simple as a loose hose clamp or as complex as a cracked block!

 

Mike,
I had things workin fine after going through this in the past, but latest coolant flush has resulted in a bit of air somewhere that the auto bleeder hasn’t evacuated. I put a new cap on too and that wasn’t the issue. I think it just has some air left in there from the recent flush that mechanic did for me not using the Airlift this time, that needs to be worked on. Auto bleeder may have failed after 5 plus years.

if it wasn’t a issue, there wouldn’t be so many threads on here about the subject.

 

My one data point is that my car collects a small pocket of air at the top of the radiator. It is a stable volume. If I bleed it out, when I start the car, it returns within a few minutes.

I keep my expansion tank level at the level specified in my Owner's Manual, which is 6 cm below the neck of the tank. The tank looks almost empty. When the engine is started cold, my belief is that there is enough turbulence in the tank to pull air into system which gets trapped in the radiator. I used to worry and frequently bleed the air from the radiator. I just leave it now.

 

I totally agree that it's an issue based on the number of posts about it. But I think it is caused by some component or combination of components that are not performing as they did 30+ years ago as opposed to some inherent problem with the design of the system.

 

I have this same issue with mine

 

This has worked for me, based on a UK 308 owner’s set up. He used plastic tubing, but I used soft copper tubing. I removed my expansion tank and inserted 1/4 OD soft copper tubing into the upper small fitting of the expansion tank. I routed the end of the tubing to the lower area, so it stays submerged in the coolant. Do not let it touch the bottom, which may close off the flow. This prevents aeration of the coolant. I clamped the upper hose at the fitting and another smaller clamp on the copper tubing near the upper fitting opening. Two years now and no air in the radiator to bleed off. I also did an Airlift on my coolant system with no leaks. After a month, some air in the radiator. Just a potential fix for some. Not wanting to debate the set up. It works for me.
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I went through all of this at great lengths two years ago, that's why I tried the auto-bleeders, new cap, new radiator, all new hoses and couplers and new water pump, all to no avail but in my case I had an actual head gasket problem that I was chasing and it wasn't until I found and rectified it that I ended up back where everyone else is. A pocket of air gets trapped in the radiator. I think that lm2504me is on to something because the bleed return line into the expansion tank does get aeriated, I've watched it at idle with the cap off and while I have no idea what it looks like under 1 bar of pressure at 7,000 rpm I can imagine the turbulence is even greater.

It's my opinion that ideally this air pocket in the radiator should not exist but it's been discussed here an awful lot and rifledriver has stated on multiple occasions that hey, it's normal and he's right in that this is what is going to happen because unlike every other car I've owned the 308 radiator does not have a bleed line at the top of the radiator back to the expansion tank. So any air that gets in there from whatever source cannot possibly get out.

So, when I had my engine out and I was pretty much going through everything I ran a 1/4 inch hose through the center tunnel along with the coolant hard lines with the intention of trying, as an experiment, to run a bleed line back to the expansion tank. I have not connected it and to be honest I have doubts that an air bleed that goes that low to a point that far distant which is at the same pressure will work. It probably won't and that's probably why Ferrari never did it. But if I could figure out what point in the coolant system is at the lowest pressure when it's all active and flowing it probably would work. Well, unless that point is the top of the radiator but I don't think it is.

Anyway this is just stuff I like to think about. In the end I believe the consensus is simply stop worrying about it. No auto-bleeders necessary. In fact I've got a set in the drawer of my rollaway if anyone wants them.

 

FWIW. The return line issue has been a standard update on Panera's that suffer a similar issue. With that said, I don’t have the air issue on my QV and never bleed the radiator.

 

When I had my Dino 246 GT, I took a different approach to prevent the aeration and to lower coolant temperatures. I purchased an overflow plastic tank and installed in the trunk near the antenna. I took the factory expansion tank to full solid with coolant. I ran a small hose from the radiator cap area fitting to the bottom of the plastic overflow tank in the trunk via an opening on the antenna side. I used hose clamps at both ends to prevent air in leakage. I added coolant to the overflow tank while the engine was cold to allow for expansion and contraction. After running the engine to temperature and bleeding air out of the engine, I had very good coolant temperatures and never ran above the thermostat set point. I also added water wetter to help with the heat transfer.
My Dino when I owned it. Previous owner attached the Ferrari badge. The other photo after new paint and new interior by next owner.

I considered doing the same on my 308. Time will tell. Basic heat transfer and fluid flow dynamics from my Navy Nuclear training.

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Well I suppose I could try it, all I need are a couple of fittings. Interestingly, if you look at pictures of an F40 radiator it does appear to have a return bleed line at the top (upper left corner) rather than just being plugged with a screw like the 308. The F40 and 288 GTO were the last two models with the radiator in the nose.

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How can it look empty when the antifreeze is supposed to be 6cm from the top of the neck on the aux tank?
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The drawing is not accurate - the entire height from the seat of the radiator cap to bottom of the tank is only 11 cm at most; 6 cm below the top is well below the mid-seam of the tank, not above the seam as the dotted line would indicate.

 

I think he means it just "looks" low because it's about half empty. I used to measure it but now just fill it to the seam line.

 

OK...clearly some folks have issues with air in the cooling system while others do not. I want to approach the issue from a different angle. Here's a question for those who seem to be routinely discovering air in the cooling system:

Why are you looking for it?

Is the system overheating or in some other way exhibiting a problem? If not, what is the point of constantly checking/worrying about air in the system?

 

Mike - for me it was the head gasket so yes, I was overheating but prior to that no, I never checked or even thought about it. But since the repair I have been checking and still think that if there was a bleed line at the top of the radiator the system would be "better". Probably not necessary but no harm in making it more efficient. If the system were perfect then when stationary and at idle on a blistering hot day the fans should cycle on and off.

Something else of note: if you look at the cooling system schematic for the F40 you'll see that the bleed line from the engine enters the bottom of the expansion tank rather than the top as it does on the 308. This is why I think an extending stand pipe as discussed earlier seems to work because it is the incoming flow of coolant dropping into the tank like a waterfall that I believe causes the aeration and that induced air eventually just ends up trapped at the radiator because there is no way out.