cooling system question

[warrenrhen]

ON my 79 spider there is a fitting/plug at the top of the top hose housing that I assume is for bleeding air out of the cooling system. Does that mean this is a sealed cooling system like the Renaults used. I thought the Renaults used those bleeders because some of the cooling system like the heater etc was above the radiator and all that space had to be bled so the water circulated right

[RRoller123]

It is a slightly pressurized system, controlled by the radiator cap. 7 or 9 or something like that psi, but just going from memory here. That T plug is for bleeding air, yes, and it sort of works, but it works well only if you jack up the front end, or add a coolant flush fitting back on the heater hose near the firewall, which is higher up, and effectively becomes the highest point in the system. Lots if useless arguments over getting the air out of the system, but whatever works is a good solution. Jacking the front end up fairly high always works, get that T as high above everything else as possible. So I do that. Massage the hoses, to get the air out. It gets trapped around the T-stat and also in the head.

[18Fiatsandcounting]

In addition to RRoller's good advice, I'll add the suggestion to make sure your coolant expansion tank is connected and filled at least halfway. In theory, when a hot engine cools back down, the vacuum created in the cooling system will draw coolant from that expansion tank and help to refill the system. In practice, this sometimes works but not always.

-Bryan

[RRoller123]

Yes, exactly! Good advice. If the level is low, air will get sucked back up into the system when it cools. You can see the top of the tube, suspended roughly in the center, of the bottle, when you look down inside the bottle. The coolant level should be above the top of the tube when the system is cold.

[RRoller123]

[18Fiatsandcounting]

The coolant level should be above the top of the tube when the system is cold.

Thanks Pete, I forgot to mention that. I've seen some spiders that got air in the cooling system simply because the expansion tank was almost empty and so air was being sucked back into the radiator when the engine cooled down.

-Bryan

[RRoller123]

including mine!

[warrenrhen]

I guess the more foolproof way, at least for initial start up would be like I used to do with my Renaults would be to hold the expansion bottle above the engine until the system is full and devoid of air. IT only takes a minute that. I may make some sort of basket tpe thingy to hold the ex bottle in place so it's easy to remove and replace.....and keep the water level above half way when cold. Thanks

[SteinOnkel]

Y'all love to turn this into rocket science.

Get one of these:

https://www.mishimoto.com/mishimoto-coo ... aHEALw_wcB

Makes filling any coolant system a matter of seconds. You have to ask yourself how do the guys on the assembly line do this? They don't have the time to fiddle around with bleeder valves, holding bottles etc etc.