Hi all Following changing the radiator in my 1979 308 GTB, it has taken me a long time to get all of the air out of the coolant system (and I still don’t think it’s all out). In the meantime, I now think it needs a new water pump. The thought of draining the coolant again, and repeating the bleed process is something I am not enthused about… I may have been watching too much Matt Armstrong on YouTube, but I was pondering attempting to vacuum fill the system. I appreciate I would need to clamp off the overflow pipe on the header tank, but I would appreciate any other thoughts on whether or not this was a good or bad idea, and any other steps necessary if you think it is a good idea. Picture of the car post wash attached to make this post a bit more interesting. Thanks all. Image Unavailable, Please Login
Just go for a few drives get it hot ( fans on ) around under 90 *c .Park up hill and open the rad bleed screw . Takes about 5-6 trips to get all the air out . Run for 10 mins with the heater on max to circulate,as well during the runs. If you over fill it it will blow it off through the overflow pipe . This assuming your tank cap is to spec ?Level should settle 6 cm below the filler hole on the tank . Try a fresh tank cap if you are still having issues ? Image Unavailable, Please Login Just done my GT4 today BTW .After an Alps jaunt . Was 34 *C in the Italian valleys . Image Unavailable, Please Login
Get an Airlift, simple, done. I now don't dread refilling the coolant. Use my Airlift, take it for drive, open the bleeder on the thermostat, and the bleeder on the radiator... done.
I use an airlift because I have a shop and use it 5 times a week. Filling the cooling system could not be easier. You cannot and do not want to eliminate all the air. The system has to have air in it. Do it like they did at the factory. I have done it that way hundreds of times. Open the radiator bleeder screw and take out the thermostat bleeder plug. Open the heater valve. Pour in coolant mix until it comes out the radiator bleeder. Ignore bubbles. Close the radiator bleeder. Continue to pour in coolant until it comes out the thermostat bleeder then reinstall plug. Continue to fill with coolant until tank is about 1/2 full. Install cap and ignore it until coolant needs to be changed again. It really is that simple. No repeated bleeding, no continual fiddling with radiator bleeder, no jacking it up or parking on a hill. All that is total bull ****.
@ Brian I did exactly that except without the t stat house bleeder on the GT4 bcz there isn’t one , just poured it in until it came out of the rad bleeder . Hmm , I still think it worth a home DIY er ( even for curiosity sake ) running it up and opening the rad bleeder once or few times more …..might as well park it nose high while you are at it too . Agree it’s simple . Appreciate in a shop you might steer away from taking them out especially in winter and test , run them up to full temperature……just eats time that could be used more productively. But a DIY er at home , retired with all the time in the world ?
And you are why there is so many wives tales and confusion. Your GT4 had no bleeder plug, most did. You are in a tiny minority and not the car in question. Might as well include Daytonas too. Stick to car in question and facts at hand. Quit making it harder than it is.
In reality I have an airlift because of 360's. If all I ever worked on was 308 and 328 Id never have spent the money. They are just brain dead simple yet in typical internet fashion it has been turned into some complex operation. Mass stupidity.
No one ever accused me of being smart that's for sure When I got mine it was for a couple of reasons. I had to replace every hose in the system and the radiator, so I wanted to make sure there weren't any leaks. And there was a leak (forgot to tighten the rad sensor) so for me it was worth it because it saved me wasting coolant.
You can still bleed out air at the thermostat housing by loosening a hose clamp and carefully inserting a very small screwdriver under the hose to distort it and create a temporary "leak".
The tank is significantly higher in the GT4 compared to a 308. There’s a small vent pipe back to the tank from the T stat housing . After a coolant refresh / fill up you can see air burping back into the tank ….bubbles when you initially run it without the cap . That’s probably why they deleted the bleeder screw in the T stat house bcz air can escape upwards into the tank . Mines a mk2 single dizzy motor FWIW ?
I think that you have that backwards -- they added the thermostat bleeder screw to both 308B/S and 308GT4 circa 1978 as shown here in the 1979 308GT4 SPC: https://www.ferrariparts.co.uk/Diagram/Ferrari/308-GT4-Dino-1979/016-Water-Pump-And-Piping If your "1979" doesn't have one, either they were using up the old part, or it was made before the change-over, or someone swapped in the older part. Of course, "model year" is rather iffy for the euro versions of that period so date of manufacture would better characterize your 308GT4's "year".
It a late 76 . Italian first reg . Generic parts diagrams , I wouldn’t hang my hat on them . Helpful as they are there are discrepancies from time to time .
Yes, then yours would naturally not have a thermostat housing bleed screw. You made a claim: "That’s probably why they deleted the bleeder screw in the T stat house bcz air can escape upwards into the tank" -- if you have some evidence for that, please post it. The 1976 308GT4 SPC shows no thermostat housing bleed screw. The 1979 308GT4 SPC shows that they ADDED a thermostat bleed screw. Claiming that the SPCs often have errors is not evidence of your (false) claim.
The man is right as usual. I could bleed air out of my 328 radiator every time after I've run the car. Absolutely no idea where it comes from, but its always there. I have pressure tested the system umpteen times & it doesn't leak. So I gave up bleeding it years ago & the coolant level in the tank is always the same. In my experience the settled level in the tank (cold) is a bit below half way, if I put any more in it just spits it out the next time I use it.
