Okay, what happened? Coolant related.

Bad cap or a bad radiator fan. If it is an OE cap I can tell it is bad from here.


Congratulations for escaping California.

 

How old are the hoses? They will start to leak eventually. Mine just did but only after a major service.

 

Did you flip your cabin heater on during this drive but not on the last? Could air be getting in via a leak somewhere in the heater matrix? Try a bleed, top up and another run without cabin heat to confirm?

 

Yep. Try bleeding the air out of your system. Air in the system will expand--especially when you stop the engine--and force coolant out.
See my thread about Automatic Bleeders. Otherwise Birdman has a great write-up on bleeding.
Cheers,
Robert

 

A temporary fix which worked on my last 308 was an Aladdin valve <£10 in the UK. It won't fix the source of the leak, of course, but should buy you plenty of time. More details in this thread: http://www.ferrarichat.com/forum/308-328-sponsored-yellow-compass-group/373050-another-automatic-radiator-air-bleeder.html The Aladdin Autovent Micro 6mm (EAN # 5060123340679) worked for me as a direct replacement for the OEM radiator bleed screw. I only needed one at the radiator to solve my coolant dump on arrival back in the garage problem and it took 2 minutes to fit.

If you need to bleed like this, a leak needs fixing, but plenty on here run long term with this little device working its wonders. It was invented for creaky old hot water domestic heating systems in the UK where ancient hidden pipe joints often micro leak and plumbers want a quick fix instead of ripping up floorboards.

 

I dont see how this bodge will cure the OPs problem. If the coolant is boiling over when idling or after stopping, it means there is a leak and the system is not pressurising properly as it heats up. Pressurising raises the boiling point of the coolant. Bleeding the system, manually or automatically is not going to prevent a leak from causing the system not to sufficiently pressurise when hot.

 

OEM cap rating is too low anyway....get a fresh one.

 

+1

 

Andy has a point that it is possible there is air Still getting into the system--but it's also possible that you just haven't been able to bleed all the air out since the last coolant flush.

But regardless, I and many others love these automatic bleeders. So much so, that I ordered a bunch to offer to fellow 3x8 owners. See them here: https://clarkandclarkinc.com/catalog/detail/automatic-bleeder-valve-for-308328-radiator

They will allow air out, but not coolant. And they are inexpensive and super easy to install. One for the radiator and one for the thermostat housing.
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Andy, I said more than once in my post that it wasn't a cure. But it will let the OP run for a while until the source is found. He can easily diagnose whether it's a bleed issue / a micro leak restricted to the heater matrix that can be shut off / a leak elsewhere that requires more immediate attention. For me, bodges are irreversible. This can be reversed in 30 seconds (if the engine is cold ).

 

Still dont get it.

The problem is caused by a leak which is letting air escape. Likely the cap as Brian suggested earlier, or somewhere else. This is nothing to do with an air pocket in a location such as the top of the rad, which would be bled out. It doesnt appear to even be a temporary fix.

The point is, there should be an amount of air in the system. It would be at the top of the header tank but if there is a small amount of air in the top of the rad thats also fine and would not be a problem. Some air always ends up there. If there were no air at all in the system it would burst when heating up owing to expansion of the non-compressible liquid.

Once the system is initially bled, adding an open-to-air valve would make things worse as it would limit the ability of the system to pressurize. Air is constantly being removed from the system. In a correct system, with no leaks the air should not be constantly exiting the system. It should be sealed.

 

So for a perfect diagnostic run a little hose from a T connector on the small hose on the expansion tank with a pressure gauge in the cabin or in the back window and watch it.

 

Another way is to first replace the cap to eliminate that, then buy an inexpensive cooling system pressure tester from Ebay, pressurize and see if it holds pressure. If it doesnt, look for the leak.

 

And the leak may well be pinholes in the expansion tank.

 

And that cold be but it can be diagnosed in a minute or two. Never mind the fact that if the cooling system has been so poorly cared for it needs much more than just a new tank.

 

There is a reason Ferrari has two bleeder screws in the system, and it is because air pockets/bubbles in the system can accumulate at these high spots and stay there. And they are not fine. Air is an insulator which inhibits proper heat transfer, and per our discussion these bubbles also will expand and contract with temperature, forcing coolant out. The origin of these air pockets in my mind is usually from the last coolant change, rather than from any holes in the system. But they can be caused by overheating/boiling or running low on coolant as well. But regardless How they get there, they should be bled out, they should not be left.

There is no chance of the system bursting. It is a low pressure system (only slightly higher than atmospheric pressure) that vents to atmosphere if it reaches the rating on your cap. The air at the top of the overflow tank acts as a buffer for expansion and contraction of the liquid and for small bubbles emerging from the system to escape. There is not supposed to be air anywhere else in the system. It should be bled out.

And when bleeding your system, either after a coolant flush or because of accumulated air in the system, one can either do it with the factory bleed screws which is an amazingly frustrating PITA job (see Birdman's bleeding tutorial here: Bleeding the Ferrari 308 Cooling system), or by using one of these Automatic Bleeders. I don't see why Anyone would not use the latter.

Robert. BSME Purdue 1987

 

You are incorrect. Those bleeders are for assembly only. Once bled no further service of any kind is due until it is time to change the coolant. We have owned a 328 for a number of years and I have worked day in and day out on Ferrari since the cars still had carbs. If any greater attention is required to the cooling system it is not functioning correctly and should be fixed, not have ill thought out band aids applied.
I do use one of the air powered bleeders and there is no better way to fill the cooling system.

Your analysis of the origin of the air pockets is incorrect. The system must have air. It will collect in two spots, a small, harmless amount at the top of the radiator and a greater amount at the coolant tank. The system cannot operate without them. Later cars had a bleed hose from the top of the radiator to the tank to get rid of the small pocket at the radiator but 308 never had that and works just fine with a small amount of air that is in the tank portion only that has almost no heat transfer function.

Instead of using a car with cooling system deficiencies to understand how it works look at the cars that are working correctly for a base line.

 

The bleeders are there for "assembly only"? Do you mean just for the time you change coolant? I think we are agreeing that the system must be bled, but you are saying that the system should never need bleeding after that?
In a perfect world, maybe so, but I am not convinced that systems are always bled perfectly.

I don't agree that "the system must have air." Ideally there would be zero air in the system. The air in the top of the overflow tank is really outside the system, and serves only as an open end to the system. Air that collects in the top of the radiator is not harmless as it is in the middle of the system, and it's expansion can cause unwanted fluid flow to the reservoir. A bleed hose from the top of the tank to the reservoir as you describe sounds like a terrific solution. But since we don't have that, any air there should be bled.

 

When these cars were "current" I'd bet money that NOBODY had to periodically take their 3x8 to the dealer every few months to have air bled from their cooling systems! So that's the baseline. There should never be any need to periodically bleed in a properly functioning cooling system.

Does anyone need to take their Toyota or [insert any car brand here] in for that?

 

Utter nonsense.

 

Have you considered that perhaps that is exactly why Ferrari added the radiator bleed hose to the 328? To solve this problem?

 

Brian, I thought this was a supportive community.
There's no need for such disrespect.

I'm not an idiot. I have been working on cars my whole life, and I am a mechanical engineer. Guys like me design these systems. I don't pretend to have all the answers, but I do know a little bit.

 

Different car, different cooling system and very different needs.