308 Cooling Issues

I think your figuring it out the hard way, and it looks like your being careful. One thing is you cant fill the reservoir to the top, it needs room for expansion. Keep bleeding the radiator. If it gets to much air it airlocks and wont flow. I think you already figured that out too. Arent old cars fun???

 

I fill the external tank to about 1" BELOW the bottom of the filler neck, use a 1.1 bar radiator cap and when bleeding air, make sure the heater vent levers are on heat !- air often gets trapped in the heater core. (bleed with the engine running too, is what I was told.)
Make sure BOTH radiator fans are coming on as well, at about 195 degrees.
(you may want to replace the fan temp sensor with a 180 degree (vs 195 degree original), so the fans come on sooner)

 

To be safe and it is ok, leave the expansion tank half full as this is why they called it expansion tank, leave some room for it to expand, but of course do this only after you have bled the system.

 

Here's what you want to do to properly bleed the system. ...http://ferrarichat.com/forum/showpost.php?p=135067366&postcount=25

I'm fighting the same thing right now after my car had been sitting for a while. I've bled it at least four times and am still getting air out of it. To be honest somehow air always seems to get into this system. I still think it's something about the design of the expansion tank myself but I haven't figure out how to fix it. And as was already mentioned, it will lock up and nothing will flow to the radiator if there is enough air in the system.

I usually warm up the car and bleed it before just about any drive.

 

I know it's not advisable and it's a bit of work but just for temporary, remove the thermostat and see if you get any flow to the radiator. If you still don't get flow then you know something else is restricting the flow or I wonder if the impeler of the pump is turning?

 

You have the heater on full when you bleed the system? You have the hoses connected correctly on the radiator and not reversed? You're sure the head gasket is okay?

At some point one would suspect the radiator itself is bad.

Ken

 

So- if you keep filling the expansion tank, with the bleeder off of the radiator, and the engine cold; you never get coolant out of the bleeder? Just keep filling until you get coolant out of the bleeder.

My first guess is that you are VERY low on coolant (it holds more than you think) or have a block somewhere.

 

One point here is that not only does the 308 thermostat have a valve that opens, it also has a portion of another valve that must close to get the coolant flow to go the radiator (i.e., if you remove the thermostat this will not direct the flow to the radiator -- see page C10 in the 308GT4 WSM). IIRC, there is a figure that shows the required minimum deflection when warm to make sure that this other valve closes, but can't recall just where (someone please post if you've got it).

The small hole in the flange is a normal (and useful) feature to help bleeding. Although you don't have the bleed fitting on your thermostat housing, you still can bleed at that location by removing the clamp from the large hose and inserting a small screwdriver (or other small diameter object) between the large hose and the aluminum housing to create a temporary opening/leak.

Can you confirm that your thermostat looks like these jpegs? Just a stab, but if someone tried a substitution to save a few $ could/would be trouble -- just a thought...
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See page C10 in the 308GT4 WSM -- the figure describes how the opening valve and the closing valve work in unison to redirect the flow to the radiator.

 

Working thru the same issues on my car (see thread: http://www.ferrarichat.com/forum/showthread.php?t=164437), its a 84 308 QV.

I changed the cap from the original Ferrari to a STANT replacement (dont have the number handy) and that has helped with the spewing coolant.

The temp of my car runs COOL in cool ambient temp (its 55 degrees at night here in colorado) but it will heat up / overheat (220 +/-) in 85-90 degree ambient temp.

I also have suspiscions about the thermostat being incorrect as well as the radiator being clogged.

Both fans turn on in my car, but the air flow is very weak (I can barely feel air when I put my hands behind the radiator). I'm upgrading to the "Birdman Fuse Box" as soon as he sends me one in hopes that the current will be increased to my fans.

ALSO NOTE: As someone else mentioned, the water temp sensor must be mounted somewhere in line with the headlight circuit. When I raise my headlights, the water temp GOES UP by about 10 degrees. Lower them, it goes down. Definate interference between the 2 circuits / wires.

Here is another recent thread about coolant spewing/leaking:
http://www.ferrarichat.com/forum/showthread.php?t=131705
I didnt review it, but this seems to be a common issue.

ALSO NOTE2: Replacing the cap helped out TREMENDOUSLY with the bleeding process, not nearly as much "foam", out of the radiator, its usually air then straight to coolant.

ALSO NOTE3: Be VERY GENTLE with the radiator bleed screw, its brass and does NOT require much torque. I overtorqued mine and broke it and had a heck-of-a-time getting a make-shift replacement.

James in Denver

 

Go here:

http://ferrari.jenkins.org/books/

You can download a .pdf copy of the 308GT4 WSM.

 

This is related to the water temperature gauge and the dash lights sharing a common ground in the instrument panel (and a lot of needle motion indicates a poor connection from this instrument panel ground to the main chassis ground). On most cars you might get 1/2~1 needle width of motion lights off vs lights on, but, if yours is 10 deg, you might investigate how to better ground your instrument panel to the chassis -- just a suggestion.

 

Ah, ok....

Its 10 degrees of water temp, or between 1/2 and 1 needle width of motion, sounds just as you describe above.

AND FYI, it happens only on lights UP not lights ON/OFF. With the headlights in the raised position but the bright stalk to the up position, the headlight beams are off but the light housing is still up AND the needle is still moved, turning on off/lows/highs does not impact the movement.

Lowering the headlight housing DOES impact the movement.

James in Denver

 

You are mis-reading what I posted -- the needle movement is related to the DASH lights being on or off (not the headlights). When the headlight buckets are up, the dash lights are "on" even if the headlights themselves are "off".

 

Like many have stated, I've been down this road before. At this point, I suggest that you replace the thermostat, and if possible, get a housing with the bleed fitting. Open up the heater valve. When installed, jack up the rear of the car and add your anti-freeze until it comes out of the radiator bleeder. Close off that bleeder, lower the car, open the bleeder on the thermostat housing and continue adding anti-freeze until it comes out of that bleeder. Close off the bleeder, fill the expansion tank about 1/2 to 3/4 full, and take her for a ride. You may have to rebleed at the thermostat housing, but I have never had any problems after that. Good luck and keep us posted.

 

Yep, I mis-read because someone else prior to that had mentioned it was the head lights. I assumed thats what you were talking about, but yes, it would be the dash lights. I also notice it affects other guages, I assume thats normal as well (slight movement only).

Sorry about the thread hijack.

James in Denver