78 308 Coolant Question

my 78 308 GTS has always run hot. in Northern Cal, when the weather is above 80 and I get stuck in traffic the temp creeps up too high and i have had to pull over the let it cool down. Having read many of the threads on this post, i decided to drain, flush, fill and bleed the system this weekend. I fot one of birdmans ez-bleed bolts, and used his good write up on his website (thanks for both of those). After having filled the system, i bled the front and back a few times. Then i fired the car up to get it up to temperature to open the thermostat. Despite holding the revs at 4k for 10 minutes, i couldnt get the fans to come on. Priior to today, if i ran the car at 4k in the heat without movement it would get the temp up high enough to turn the fans on easily, if not overheat. I am thinking maybe i had big air in the system before, and just the refill and initial bleed put me in a much better position. any thoughts on that. I am planning on taking the car out, driving it around and getting the temps up that way before the final bleeding.

also, how the f*ck do you bleed the thermo housing without burning the crap out of your fingers? Wait until it cools down? Remove the aircleaner assembly?

lastly, when i fired the car up without the aircleaner assembly i notice chuffing from one of the carbs....put the aircleaner assembly back on and no chuffing...at least not that i could hear.

 

I use a pair of leather linesman gloves when working around a hot engine.

 

Took me awhile to find it from recollection but here is a fantastic thread: http://www.ferrarichat.com/forum/showthread.php?t=136346&highlight=bleeding

I also have a '78 and I have often driven it in near 100 degree conditions with no overheating. Sounds like maybe the thermostat isn't opening fully, air in the system, radiator plugged up, fuse block issue for the fans, or the switch for the fans isn't working properly. I am not sure I trust my gauge - have been thinking about getting one of those fancy hand-held temperature reading devices. Good luck.

Seamus

 

Couple of things:

1. If you haven't already, plug the upper hose to the coolant expansion tank.

2. You say the fans aren't coming on, but is the temperature gauge indicating the engine temp is going into the normal range? Due to the design of the cooling system, it holds a lot of coolant. Full change out is about 5 US gallons. That is a large heat sink. Takes a while to get all that coolant up to the temperature required to turn on the fans, and there is no need to do that if your objective is simply to bleed the system.

What I do is the following:

a. Bleed system cold, right after filling, using front and rear bleed screws.

b. Start engine. Bring engine up to operating temperature (i.e., thermostat open - radiator fans not on). Bleed thermo screw (i.e., rear screw). Bleed radiator screw (front screw).

c. Take it for a short drive (say 3-5 miles).

d. Let sit for a minute or two, then bleed radiator.

In my experience, any residual air is going to make its way down to the radiator, and can be bled from there.

If you have plugged the upper hose, have no air collecting in the radiator, and the car is still having a cooling problem, then something else is wrong (e.g., bad radiator core, bad thermostat, bad radiator cap, bad thermo switch on radiator, bad relays).

Bob
'78 308GTS
'01 Corvette Z06

 

Thanks for the help. I searched the archives, installed birdmans EzBleed bolt, followed the instructions on his website (thanks!), and all is well.

I went out to napa this past weekend where it was pretty hot, and the sucker stayed right at 195 after a single bleeding.

I am not much of a contributor as i am just building confidence working on these cars, so i want to make sure i posted a "thanks" to all those that do contribute on this site. Very helpful.

Geno
'78 308GTS

 

sledge4.2 ... check out this thread too:

http://www.ferrarichat.com/forum/showthread.php?p=137925677&posted=1#post137925677

Because your car's a 1978, and you've probably got a vertical tank (i.e., without the internal tube that's discussed in the thread), you might benefit from plugging the upper hose into the coolant tank.

 

Glad to hear you got it sorted out.

I have added a little tutorial on troubleshooting overheating 308s on my site

http://www.birdmanferrari.com/coolant/coolant_troubleshoot.htm


Birdman