I am swapping my engine's "heat exchange" unit in my 90 GT for another of the same brand, but without the two separate oil reservoirs. Can anybody tell me the proper procedure to "burp" the cooling system?
Thanks in Advance.
Don Hanson


Once you've filled everything, burp the system by squeezing the lower radiator ...uh, heat exchanger hose.
Keep doing this and adding water/anti freeze mixture until no more bubbles .....


Dave, Don,

Only thing I would add which should be obvious is that the system needs to be warm enough for the thermostat to be open for this to work well. Where some people run into trouble is when they allow a big bubble of air to superheat in the engine before the thermostat opens so that when it does they have a geyser and maybe a warped head. So filling slowly with the heater on and monitoring are the best way. Let the pump slowly move the bubbles through the system. Keep the level down for a while so that you can massage the radiator hose near the thermostat housing without overflowing the reservoir as Dave says while filling in small stages and watch for signs that the engine is getting hot. It happens pretty fast when it happens. And don't, repeat, don't leave the cap on while this procedure is playing itself out.

To recap: Heater on full hot, cap off, fill slowly leaving level down a bit, watch for signs of engine over heating while massaging radiator hose near the thermostat inlet. Go and drive it when you think it is stable. Up and down hills, left and right, start and stop. Then recheck it. Done.

Oh yeah, it helps if you park the car nose up when filling. Some will say nose down but nose up makes the bubbles from the heating system rise toward the front of the engine to the thermostat area the fastest. It is the engine side that causes the trouble not the "forward mounted coolant to air heat exchanger" side.

I have geysered and lived to tell about it.

Jay K.
79 US 5ish speed