Air in cooling system

Well, as has become common in politics these days I'm going to "walk that statement back" I did a test drive yesterday, about a ten minute loop from the house in motion the entire time. The gauge never got past the 195 mark, in fact it pretty much hung around a needle past the second mark but as I pulled in the garage I could see the trail and coolant was coming out the overflow. Not because it was hot but because the air had displaced enough in the radiator to overfill the tank.

I did another two block tests before and after that run, both negative. I even checked the block test fluid by just breathing into the tester as I squeezed the bulb and it changed color so it's pretty sensitive stuff and seems to be working.

I bled the radiator and refilled the tank and did another idle test with the heater hose clamped off. Seemed to do better but when the fans came on they stayed on and it kept creeping very slowly upwards and after about 20 minutes coolant started dribbling out the overflow with the gauge a needles width past 195.

Another bleed, another test this time with the manifold bleed line clamped off. A bit better this time still, held at the 195 mark for a long time with fans running but eventually began to very, very slowly creep past when I ran out of time and had to shut down and go to work, scratching my head.

I had been going over my service records and honestly, it may be in there but I don't see a water pump replacement or rebuild mentioned anywhere. I've been doing research on water pumps since before I put the new radiator in and it's really confusing as to what's available out there or even what it is that I currently have on there. So I made the decision to just get one of Nick's pumps from Forza despite the cost. It has a proven record and I have no problem with a part being overkill for my Ferrari. So I called to order one and talked to Nick for ten minutes explaining all that I've been going through and he seemed to be of the mind that I'm just not done bleeding the air out of the system.

I went back and read a bunch more old threads on this subject and see so many people describing the exact same symptoms as what I am experiencing. The problem is that the solutions, or what they ultimately deem to be the solution, are all over the map. A new pressure cap, a new thermostat, a radiator recore, a water pump, a leaking heater core, the heater hose nipple on the head....on and on. Perhaps I should be heartened at least by the fact that I do not see a bevy of people with blown head gaskets.

Anyway, I have two more main line coupler hoses to replace at the thermostat below the plenum and I'm going to install my new water pump on Saturday and see where it goes from there. I wish that Aladdin auto bleeder thing I bought from Clark and Clark actually would work. If it could continuously bleed the air out of the radiator I could just keep topping off the tank after runs until it was all out but for some reason it doesn't seem to do anything. Acts just like the original bleed bolt.

Saabguy - on the fans, they are new Spal low profile shrouded units, I think 9 or 10 inch. They should be perfectly adequate but until I've tested them I'm not making any recommendations. They are spinning the right direction and no need to bypass the switch because when they turn on, at the correct temp, they stay on because they never bring the temp back down to the cutoff point. I also did a test where I put a bug house fan against the nose to supplement them but tit still didn't solve anything. Once I get this air issue sorted out I'll be able to see how they actually perform. I did no modifications that would prevent me from just putting my OEM fans back in although I think I'd have to pull the radiator or the spoiler to get them in there.

Wish me luck guys, thanks for all the feedback, tips and speculations, one of these days I'm gonna lick this thing.

 

There’s a 109671 in the box on eBay for $349.00

 

The one I got from SF is the Wahler.

On a side note I did some research on the Aladdin auto bleeders I got from Clark & Clark. The way they work is there is a hydroscopic washer inside that expands when it contacts water and seals it. So it will never work in this application because as soon as you bleed the radiator and screw it in it's wet and will never function as a vent until it becomes bone dry again. I'm going back to the original bleed screws. I stumbled onto another old thread where people were fabricating a more elaborate auto-bleed system with a float actuated bleeder for home heating radiators but I can't help but think you're starting to create some sort of Rube-Golberg contraption by going down this route. A more elegant solution might be to just plumb the radiator bleed port all the way back to the top of the expansion tank the way it's done in just about every other automotive cooling system I've seen and, from what I've read, the way it's done on the F40 which if I'm not mistaken was the last mid-engined Ferrari model with the radiator located in the nose. Not sure how difficult it would be to fish a 1/4 inch line through the rocker alongside the heater hose and brake booster line though. Probably not easy. Might be a good idea to add a line like that though if you're replacing those hoses in case you ever decide you want to hook it up. It would certainly up the efficiency of the system by completely eliminating the trapped air pocket in the radiator. Another idea I've seen is to just make a bleed screw with a nipple and hose with shut off that I can use to bleed the system as it's running since all of the air seems to eventually get trapped at the top of the radiator. This would be used just to aid in bleeding after refilling the system and would be removed and replaced with the original bleed screw after I'm done.

Anyway, my next step is the water pump which should arrive today. I'll take some pictures.

 

I agree with all you're saying Mike except this part. If air gets in the system (from whatever source) it's going to get trapped in the radiator because there is no way out. It is then displacing system volume. I've been observing this first hand. I start with the coolant tank about half full, run up to operating temp, shut down, let it cool and when I open the cap the tank is completely full. I then open the bleed on the radiator, air escapes and when coolant starts coming out the level in the expansion tank is back to where it was when I started.

But you are absolutely correct that they didn't spend days or weeks performing elaborate bleeding operations on these things when they rolled off the assembly line and that's why I am methodically going through this problem in an attempt to fix it properly with no modifications to the system as it came from the factory. (outside of a different radiator fans and waterpump, but those are not actually changes to the system design)

 

John - please read through my entire thread, I have done block tests at least half a dozen times all with negative results. I even ran out of test fluid and had to buy another bottle. I was so skeptical I went so far as to test the test fluid by breathing into the inlet of the test tube while squeezing the bulb and it did indeed change color so I know the stuff works.

How definitive is the block test? Not sure but it seems if that much air is coming from the combustion chamber it should surely set it off. I have tested in pretty much every condition including hot. I hear what you are saying though and struggle myself to figure out how air could possibly get into a closed system that is 16 psi above the pressure of the atmosphere surrounding it.

Mike - this whole thing is not about there being an air pocket in the radiator. This is because my system is not doing what it is supposed to do and is overheating. If it performed normally I wouldn't be here posting and I wouldn't give a hoot how much air was in my radiator.

 

Mike - I got the car in Fall of 2016 and there were no problems, it did not overheat. I don't know if there was air in the radiator because frankly, I never checked. This getting hot issue started about six months ago and I have been dealing with it since then. I have put about 9,000 miles on the car since I bought it. I started with a new pressure cap then took a peek in the top of my radiator, this is what I saw. I considered having it recored which you can do, it won't be identical but close enough if you are a stickler for originality.

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I opted for the aluminum radiator that Nick sells. Just my choice, a recore would have been just as fine.

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Got my new water pump and the old one off - looks fine, no smoking gun here


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I was highly relieved however to see that the inside of my engine doesn't look like the inside of my radiator. I was a bit worried about that. I wonder if those scale deposits have anything to do with the fact that there is air up there? Don't even ask me about the debris, I have no idea what that is.

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John - the distilled water is just temporary while I troubleshoot. I just drained the system again to do the water pump and believe me it is a heck of a lot easier to deal with four or five gallons of water as opposed to glycol mix. I have a 1.1 bar cap, water at 1 bar boils at 250F and I'm not getting anywhere near that. If it continues to rise above the 195 mark with the fans running I abort, no need to go any further.

Looks like I'm going to have to remove the plenum to get at the other two main line hoses that connect to the thermostat housing. I will inspect and possibly replace the bleed hose as well when I'm in there.

 

No Mike, it DID overheat with the old radiator, that's what started this whole thing. As for bubbles in the stream - yea well let's walk that one back a bit too, I'm not so sure. There certainly were when I first started it but bear in mind I had this entire thing apart, I replaced every hose in the main lines except the two under the plenum that I am doing now so it was completely empty and I expected there to be some air trapped in the system but that is what that stream into the expansion tank is for, it's the air bleed line at the top of the coolant manifold that rises up from the heads. Bubbles, at least when I first ran it, are simply an indication it's doing it's job. The problem is there is no bleed circuit for the radiator, there is a bleed port but it's closed so unless you remove the screw the air that makes it up there is trapped.

Anyway, I'm glad I pulled the water pump. If you look at the bolts in the picture you can see they are badly rusted. I think whoever did the water pump service last maybe thought it would be a good idea to clean the bolts up with a wire brush which unfortunately removed all of the plating so they had no corrosion protection. Another year or two and they might have begun damaging the housing or even the block. So I'm looking for a set of M8x1.25x70mm bolts online now. I'm also seeing what looks like possible leakage around the hose to the lower port on the housing which is the water pump suction side.

Maybe I'm on to something, we'll see...

 

Possible smoking gun? This is the hose that was connected to the lower tube of the thermostat housing that is the suction port for the water pump. This does not look normal, no other connections and there are a LOT of them, looked like this.

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