308 coolant vacuum fill

This post should be pinned to the top of the forum list near the buying guide.

 

After all these years I now only read these threads to see what sort of new mental gymnastics people go through to try and explain a little air pocket in the radiator.

 

A hundred years ago I worked for a shop the specialized in Alfa's, Fiat and Lancia. Later for a short time at a Maserati dealer. I was taught the only problem with air in the system was getting a pocket that kept the system from flowing the coolant. The Fiat Spiders were the worst about this. The X1/9 was never that bad about air in the system. When I did some work on my 308's coolant system I did ask some questions about refiling believing there may be some trick to it but after working on it, it seemed just like my X1/9. I hope this does not cause anyone to have kittens but the 308 and X1/9 really are not too different. the coolant system is the same.
@Rifledriver explanation of having some air in the system is ok does make sense.

Any way, fun thread I have learned.

 

There are some Ferraris where proper filling is problematic. 360 is one of them and without a vacuum filler it is very difficult. 308 is not one of them yet the stupid stories of filling and bleeding persist.

 

I had a problem filling my 328 just once where I got an air lock at one of the heater boxes. It was relatively easy to just loosen off the pipe at the valve there & let it out. Other than that, as you said, its not difficult to do.

 

After adding an overflow tank to the expansion tank, I never had to burp the system again. Most of my problems were a cause of how the expansion tank is designed.

 

My 328 would burp regularly until I discovered that it had the wrong type of rad cap. Once the correct type cap was installed it never did it again other than an initial burp if I overfill it when doing a coolant change.

 

I do mine every 5 years when I replace coolant. Never open bleeders or cap any other time.

 

What’s the point , function , purpose , raison d etre of the fwd rad bleed screw ?

ANYBODY !

 

To relive the air lock that would take place while filling without it. Thats very obvious and has been described by me in every one of these stupid, meaningless threads.
It is not to remove every cubic centimeter of air because it will be replenished constantly.

 

Sitting level in my garage the expansion tank (In fact the half way full point) is higher than the top of the radiator. So I remove the radiator bleed plug and pour coolant into the expansion tank until it comes out of that port. Done.

Believe me, I went through all of this ad nauseum a number of years ago because I had a problem with air in the coolant system and engine overheating. So I read every post that had ever been made about it but here's the thing - I had a blown head gasket. So I actually did have a problem. After fixing that I still have an air pocket at the top of the radiator but my engine doesn't overheat and I don't lay awake at night worrying about it.

And just to clarify when I say engine overheating I don't mean it went a couple of needle-widths past the 195 mark I mean it kept going until the light came on and I had to shut it down. If there is a problem and it's going to overheat it doesn't matter how many seals you put around your radiator or how soon you turn on your fans or whether or not you bled that little air pocket out. Nothing will help until you fix the actual problem. If you don't have an actual problem the temperature will stabilize, even if you "think" it's too high.

 

Beating the horse here.

I replaced the washer with 2 Viton o-rings. One inner and the other on the outside to prevent rollout. (Because I'm a neat freak, I may buy a sheet of Viton to fabricate a "washer".)

My hunch is the copper crush washer had been crushed too much and lost its malleability over time.

Results: No more leaking at the radiator bleed valve or air being sucked back in.

Man, this site is great. Much appreciate everyone's insights.

 

There is no vacuum in the cooling system at any time. If the pressure drops below atmospheric pressure, air enter the system through the valve in the cap on the expansion tank.

 

With a properly functioning cooling system, Yes. But air does enter if it's easier to enter through a hole in the radiator bleeder like mine. Path of least resistance. But I've solved that problem now.