Where did all this air in my radiator come from!?!?!

Are you opening the heaters when bleeding the system?

 

As described, those are classic blown head gasket symptoms....

 

I had the same problem and it turned out to be the heater hose where it outlets from the rear cylinder head ........... it hose failed and appears to have been sucking air in when cooling down , , the reserve tank didn't drop which is odd to say the least.

 

The only reliable way to tell whether or not you have any leaks is to do a pressure test. Even a small leak, which won't be detected by visual examination, can still let enough air into the system to cause the problems you describe. Any auto shop can do a quick pressure check for you.....

Make sure you ask them to perform (2) tests --- one with the system HOT and the other with the system COLD --- checking both temperature conditions is CRITICAL for finding small leaks!!!

Don't worry (panic) about bad head gaskets until you have some more info ---- 9/10 times the leak is from something trivial (e.g., bad hose, loose clamp, bad radiator cap, etc.).

Good Luck

 

Extremely premature to jump to that conclusion ---- let's not scare the poor guy to death!!!

 

Check see if you have numerous small bubbles in your oil, or brownish oil (assuming you’re not using synthetic of course).

 

When opening the cap, the release of air pressure is caused by a buildup of heat (molecules are pushed wider apart) which cannot escape. Perhaps your radiator's thermostat is stuck. http://www.ricambiamerica.com/parts_catalogs.php?V=diag&I=2470

(Part No. 60)
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Thats a temp switch for the fuel injection. It has no cooling system function.

 

"Thats a temp switch for the fuel injection. It has no cooling system function."

Too funny! When I saw that switch for the first time I assumed it was a coolant level sensor and never paid any other attention to it other than thinking, "Hmm...I don't remember seeing any sort of coolant level warning light or anything on the dash...must have missed it." But again, I didn't really pay much attention. A few months ago, when I had the coolant changed I again thought, hmm, wonder why I don't see a warning light since the coolant level is definitely LOW (turned ign key on doing some other check when old coolant was drained). But I thought, "Guess I need a new one...I should check out the owners manual to see where that warning light is!" Thanks: now I don't have to buy a new "coolant level sensor."

Re scaring somebody (head gasket). My intent was not to scare anybody but OTOH, the first thing to do is to be aware of the possibilities. Certainly one would check the immediately easy and obvious stuff - loose fittings, etc. BUT coolant disappearing with no external signs of leaking, if that is indeed what is happening, is frankly not likely to be any issue with fittings, settings, radiator caps, etc. Failure of any of those items will normally cause coolant to be dripping/spraying from somewhere, accompanied by the obvious smell of hot antifreeze (if you are using antifreeze). If a radiator cap sticks shut and cannot release at design pressure usually a hose/clamp somewhere will let go first, again, providing you with a pretty immediate and dramatic visual that something is awry.

As noted, a pressure test should pinpoint the problem...

 

I don't mean to alarm you, but I was one of the very unfortunate ( and few) 328 owners that actualy had a serious problem that presented the same symptoms. A Block Gas Analyzer test is easy to do and the kit is available at parts stores ( it will confirm that exhaust gases are finding their way into your cooling system). If your intreseted here's a link to my experience.http://www.ferrarichat.com/forum/showthread.php?t=147367

 

Be very careful. A really good spot for that bolt to hide is inside the cam belt covers.

 

Sorry 'bout that, Chief

 

"And I don't have any signs of oil in the coolant or coolant in the oil."

There are 3 common ways that head gaskets fail -

1. between adjacent cylinder combustion chambers, no water jacket or oil passages breached - just loss of compression in the cylinders involved;

2. Failure between the combustion chamber and the coolant passages - coolant "disappears" and coolant temp varies widely. This is quite commonly one cylinder only but can be multiple.

3. General failure where the combustion chamber, oil passages and water jacket passages are compromised, allowing oil/coolant to mix.


#2 can be difficult because a static compression check, which many folks believe will identify a bad head gasket, will often show good compression. A leakdown test is foolproof though more trouble. The disappearing coolant and varying coolant temps is the most characteristic symptoms of this type of failure.

Head gaskets blown to the outside of the engine are, of course, a snap to identify, both from the noise and frequently the pumping of oil and or coolant that may occur.

 

Get the easy bleed replacement from Verell (http://www.birdmanferrari.com/ez_bleed.htm) and never have the problem again.

 

They're 'on the shelf', see this thread for pix & ordering info in post #1, current price in post #5:

http://ferrarichat.com/forum/showthread.php?t=184590

 

Or none of the above....and the coolant nipple/hose under the plenum is rotted out, leaking, corroded like 99% of the cars I see, versus the 1 car in 300 that actually has a head gasket problem. A cold seep at this hidden hose will allow air into the system, with little evidence of coolant loss...and cause all sorts of air in the cooling system, replicating the above problem.

 

I can't visualize which nipple/hose you are referring to. Can you post a diagram or pic?

 

I had exactly the same thing , , ,the leaking coolant from the rotten hose was being vaporized before it could congregate anywhere .......... a clue is a faint hissing noise. In pitch dark with a good strong flashlight you can see a small amount of vapor rising from near the rear left cylinder.

If it's that hose you might as well do the brake booster hose too , , they're good buddies and go everywhere together.

 

I'm pretty certain Fastradio is talking about the heater hose ............ mine was amazingly bad condition , , , , it is very difficult to see when looking around , even with a mirror.

It is very easy to see with the back left wheel and inner arch out.

If this hose is rotten and you just need to drive carefully home a few inches of 5/8" hose and a joiner will do the job. After that lets face it the whole thing needs to be replaced ........... see heater hose threads for that.
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It's funny that this post came up and I didn't notice. I have been working on cleaning up the lower end on my 77 after having typical oil leaks through time. I finished up the bell housing side and after drying it off and adding a vent hose to the transax. I took it for the road version of dry off. After the ride I proceeded to put the car back on the lift for overnight and noticed a few green drops on the frame rail under the trans. After investigation I see I have a weeping leak at the hose that enteres the head. Same one as above except on the carb. version. It appears to be at the clamp and after retightening the clamp it has stopped. But the problem is I can see that the hose is showing signs of age and wear. You know that slight bulge at the fitting. If I go 3" back the hose looks good but we all know that will get worse as time goes on. So as an interim fix I'll splice the hose and plan this for one of my winter projects. Good catch here with this post and I bet there are a lot of cars with this problem.

 

We have found that a vacuum test of the system is far more critical, we now do a combination of both perssure and vacuum tests when looking for a problem. The vacuum test will identify the hard coolant hoses that allow air to be sucked in where those often seal up under pressure tests.

It is the hoses going hard that allow the seapage that leads to the correded nipples. Combine the heat, antifreeze and unprotected aluminum nipples, air with the carbon compounds in rubber hose and a slight electrical charge present and..... This is the reason we designed and made the silicone hose...when properly installed silicone hose is in place it can be trusted for a long time. We found the current rubber hose to fall far short of reliable these days. Dont just tighten the clamps, you will regret that decission.

Some of the nipples can be cleaned up just fine if they are caught soon enough...some (as shown) are doomed to failure and need to be replaced. Replacement usually proves a daunting task as the factory never used sealant on the threads and time has bonded the aluminum nipples to the aluminum housing. Have a drill and taps handy before trying to remove an old one.
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