Bleeding Your Cooling System - Classic FIAT 124 Spider

Posted by Csaba Vandor on May 28th 2021

The technical tips listed below are intended to aid in the care of your Fiat 124 Spider and should be used accordingly. They are based on many years of experience but are in no way a replacement for factory recommendations. Seek the professional mechanical assistance for all issues beyond your abilities.

Auto Ricambi, LLC is in no way responsible from the consequences of applying these technical tips. By using (accessing) these technical tips you agree to these terms.

Bleeding the cooling system involves getting rid of all air bubbles after refilling the cooling system. Because the radiator cap is not the lowest point of the cooling system, it is necessary to remove any air which does not escape during the normal filling process.

Be sure that your cooling system is not hot and that the heater valve is open before starting to fill the radiator.

To do this process properly the upper heater hose needs to have 'flush T' installed. We sell this (part number CO0-001), but they are also available form auto part stores as part of a flush kit. Take the cap off the flush 'T' before filling the radiator.
First, prepare a 50/50 mix of antifreeze and water. The easiest way it to buy a gallon of antifreeze, pour half of it into another gallon container, then top both containers with water. Fill the radiator with the 50/50 mix, then squeeze the upper radiator hoses repeatedly to get the air out (watch for air bubbles coming out of the radiator's neck). As the coolant level drops a bit, refill it, squeeze the hoses again and again, until no more bubbles appear. Install the radiator cap.
If the car is equipped with a bleed plug in the coolant outlet (front top of engine), remove it. Pour water slowly into the flush 'T' until it comes out of the bleed hole. Replace the bleed plug. Pour more water into the coolant 'T' until it is full. Replace its cap.
If there is not bleed plug in the coolant outlet, then just fill the flush 'T' until full, and replace its cap.
Make sure the coolant overflow bottle is about half full. Start the car.
Normally it will take 10-15 minutes for the engine to reach normal operating temperature. Watch the temperature gauge to be sure the engine temperature does not go over 210F.
When the needle is around the '0' of the 190 on the gauge, the thermostat should open (top and bottom hoses are close to the same temperature), and eventually the radiator fan should come on.
If the engine starts overheating, shut it off, and let it cool down (an hour or so). Repeat the bleeding procedure. Some cars require bleeding 2-3 times before the thermostat would open.
A common problem on Spiders with the external thermostats is that it fails to open after the cooling system has been filled and bled. If this happens after repeated attempts to bleed the system, there are two methods of overcoming it. The first one is to drill a small hole in the valve of the thermostat, so no air bubbles remain in it when filling the cooling system. The other is to force the valve open by putting an aspirin under it to keep it open. The idea is that water will circulate freely, so no air bubbles will remain in the thermostat, and the aspirin will dissolve soon thereafter, allowing the thermostat to close and work properly.

Be aware that you will be working with hot cooling system components, so watch out so you don't burn yourself!