308 Radiator and Thermostat Housing Bleeder Assemblies

I’ve always had an idea for a means to bleed my 308 QV coolant system without the need for cast iron fingers, or using 5 rolls of paper towels to soak up the excessive coolant from the thermostat housing during bleeding. I’m always very paranoid of soaking those precious cam belts (which are right under the thermostat housing) with coolant. Cross drilled bleeder screws are a step in the right direction, but require multiple turns of the screw to get the air hole to bleed coolant, and then it is tough to capture and control the stream that comes out of these. The bleeder screw in the radiator is also tough to trap the coolant as it is being screwed/unscrewed. Well after about 5 years of procrastination (and marriage and kids), I finally made a pair of bleeder screw assemblies that use real bleeder screws instead of cross drilled holes in screws. With this approach, I can add clear tubing to the head of the bleeder screw and point the stream of coolant into a jar or container. So far the results have been really awesome with this approach. If people are interested in a setup for their 308, I could get a run of these made up. I talked with a machine shop I do business with, and it looks like a run of 25 sets is in order to get a semi-reasonable price. If people are interested, the price would be $47 for the pair, including bleeder screws, bleeder caps, brass washers, and shipping within the US. To some this might be overkill, and to others it might seem kind of expensive. The brass adapters are two different pieces, because the threads in the radiator are different from the threads in the thermostat housing, and the surface finish on the bleeder screw seat needs to nice. And to get the threads close to the transistion on the hex surface, the threads really should be single pointed instead of using a die to form the threads. I’m not sure about fitment of these on other models, but if someone had measurements of thread length and pitch, I could let them know if these would work. I’ve got lots of help from this site on my past service work and would like to help share some of my ideas. Happy Motoring!
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A really great idea!!! Better even than the EZ Bleed!

 

I'm on board...I'd like to see this come to fruition! You have come up with a great way to divert the coolant, especially at the TStat for fear of getting it all over the belt assemlies. I'll just put my stock bleeders in my parts box for the purists out there

 

....or just bleed the system with the engine off & when its cold by lightly pressurising it with a radiator pressure tester (which is never a bad thing to own anyway) applied via the expansion tank.

 

Yes...but it's still a messy ordeal. I prefer his solution, this way you can easily capture the overflow.

 

Hello Tom,
Great idea! I have been trying to devise a similar idea because I was getting fed up with the anti-freeze going to waste everytime I bled the system but did not have the facilities to develop an answer.Please count me in for a radiator bleed valve as I only have the one on my 1977 Fibreglass 308.When available please contact me, thanks Tom

 

I think the last time I did it less than a teaspoon of coolant came out the T'stat bleeder which is easily caught in a paper towel. I'd hardly call it messy, its a very controllable way to bleed the thing, you don't need huge pressure in the system, 5 PSI is more than enough . Jacking the right side of the car up an inch or two ensures you really do get all the air out.

I.

 

Also with the bleed screw in the radiator, to fill the system after a service (such as coolant change, hose change, etc.) you want to fill the system until the coolant comes out of the bleeder in the radiator. And you fill the coolant from the rear tank, and by the time you hear that coolant is coming out of the radiator, and by the time you get to the radiator to close or reinstall the bleeder screw, you have a lot of the coolant all over where you don't really want it. With this approach, you can just direct this excessive coolant into a trap jar.

I've tried pressure bleeding the coolant system, and have had mixed results. It appears that if the trapped air is within the engine, the pressure bleeding seems to work well. But if the trapped air is within the heater cores/heater hoses up high in the forward compartment, these air pockets seem to stay there until there is circulation to push these towards one of the bleeders, especially if you are filling the system from a totally drained system.

 

I am interested in a pair, but my aftermarket radiator seems to have a 10mm bleed screw and not the smaller standard one. If you could get round that then I would definitely have a pair.

 

Hello Tom,

 

Hello Tom,
Just a quick e-mail to see if you have made any progress with the replacement bleed valves.If you are unable to get sufficient orders to do a run do you have any prototypes that you would consider selling as I think they are an excellent idea.
Regards, Tom.

 

I'll take a pair and pay in advance if that helps you? Ciao, Dennis (Paypal?)

 

Hi:
So far, I've only had commitments for 5 sets total. So I will not be turning the machine shop on to make a run of these. TSP11, I do have an extra proto bleeder for the radiator, so send me your shipping address and I'll get it out to you. I'd like to hear your feedback. Other than that, I have no other pieces, else I would sell these to the parties interested. Thanks to the people who have shown an interest.

 

How about this setup.
I didn't think of it, someone else gave me the idea and i worked it out.
It's an automatic airbleeder from a central heating system.
This works perfect, no air in the radiator anymore and the temperature that was always to high is perfect now.
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Hello Tom,
I would like to thank you for your most generous offer of supplying me with one of your radiator bleed valves.I really do not understand the lack of take up for this brilliant solution to an age old problem of bleeding the 308/328 series.I know from experience that sometimes the bleeding procedure can be completed without any problems but more often than not air locks and coolant everywhere is the norm.
I can only request on behalf of future 308/328 owners who will be searching on sites such as this for an answer to their bleeding problems to keep a record of all the dimensions of these replacement valves as I feel sure you will be requested to machine a number of them when they realise that there is an ingenius solution when they first attempt to service their cooling systems and encounter the experiences that we all know about.
Once again, many thanks for your generous offer and I will let you know how I get on even though I know it will be a positive result!
Kind regards, Tom.

 

Hi jwa.
I'm interested in such idea. Could you tell us the exact make and model of automatic bleeder you have mounted? Source top buy it? How it works? You have to push the black button on top to purge the air? I think that these are interesting questions.

Thanks

 

Hi,
I'm confident that JWA doesn't mind me being you at service for this question as i'm reading this tread by coincidence.
Fact is that he's giving the simplest and best solution and without you needing to pay much money or doing much efford at all and only you are responding to it. I can't help wondering what the gain is in placing a bleedervalve where there is a better solution that will do the job automatically.
JWA was immediatly enthousiastic when he saw this solution in my car. For all I know, there's no better solution for keeping your system troublefree because you don't have to do any bleeding anymore. Just strange that you are the only one who's reacting with enthousiasm because it's the safest mod. with the least future efford. It is just like a Volkswagen Beetle. Simple but effective. Maybe that's the reason for the lack of reactions, perhaps it should be more impressive.

I would suggest to use a automatic air-bleeder with a sidelocated hoseconnection because of the limited height so you can stick to a short hose.
Use a 10 Bar (150 psi) 240 F type that is also used as a permanent bleeder for central heaters in houses.
The black button is actually a bleederscrew that you can leave open permanently. Only the air will escape until water is entering. Then it closes off automatically.
The bleederlocation on the thermostatehousing is far from sufficient and this will do the job perfect and without future fuzz.
At Toni's in Maranello, they were very enthousiastic about it and they are (by all means) guy's you can take serious.
They used to make a bypass from the radiator bleederscrew to the expansionreservoir in F40's because they knew where the best lokation to bleed air was situated. So pic your choice. I drove to Italy through Switzerland and back with traffic jams and tropical temps of an average 36-38 cels. and kept the car at 85-90(max) celsius. And here, as you know, we really drive our Ferraris fast and long distances to. I enclose a photo of my bleeder. It is not mounted so handsome as JWA's but together with his it gives you an overal impression.

Best regards,
Marcel
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Pretty good adaptation of an existing device that is designed exactly for this purpose - bleeding air out of a liquid system. The beauty of this is that it's all automatic - just like the bleeding in a home circulating hot water heating system! Looks like a really great practical solution!

 

Thank you, thank you!
finally somebody who's thinking in logical terms to.

 

Hi vetroresina.
Thanks for the information you provide us. I'm a newby on the 308 world, and I'm discovering all the tricks to do the 308 maintenance. I've found this solution a very good idea that I will use as soon as possible -I've a 308 project with lots of works to do on it-. Thanks again Marcel.

Cheers

 

You're welcome!

I'm just curious why there are no further comments on this simple but most effective solution.
IMO there should be some F-chatters on this thread reconsider there former commercial-like enthousiasm by now. Can't figure it out.
At least there could be a critical question about it. That would make sense rather than to stick to something that is actually obsolete.


best regards

 

He Marcel, i don't mind you stepping in, you gave me the idea.

The valve Marcel used is smaler than mine cause his has a connection on the side.
Mine has one at the bottom therefore i had to use a elbow piece.
As a consequence i had to put mine further back.

I mounted mine on the rightside heater radiator instead of a part of the airco.
In the airbleeder there is a float, so it lets air out continuously.
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Also to connect a hose to the radiator i made a extension.
I used some brass thread, a tube with inside thread and a brass nut.
Cut all to size and soldered it together.
I the drilled a 3 mm hole in it.

The first picture showes the original bleed screw on the top left.
Then the parts i made the extension from
On the bottom the parts cut to size.

The second picture showes the airbleeder and the extension. (i showed that before)
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Next i made a mountingpoint on the house of the heaterradiator.
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Very cool.

Can someone tell me where one gets one of these?

Also, how does the auto bleeder work? What causes it to close once fluid reaches it? (Sorry, I don't trust anything when I don't understand how it works!)

Birdman