ls6rx7

First off my 02 LSX has found its way into my 93 rx7 so my questions mainly pertain to the motor itself.

Im having problems getting any heat to come out of my heater core after replacing the coolant line coming from the two heads. I believe its because the heater core and one of the heater core hoses are up higher then the water pump and air may be trapped. Of the two heater hose nipples that come off the water pump which is the feed and which is the return for the heater core?

Also is the metal coolant line that connects the two heads the highest point in the cooling system (as far as the motor is concerned)? aka is it a good place to bleed the air from? or can air get trapped else where such as in the top of the water pump(since my radiator sits lower then the pump)?

Basically im trying to figure out the best way to be sure ive got all the air out of the system. Here is a picture and a diagram of my coolant system so you can see what im talking about a little better.

Any suggestions are greatly appreciated!



The only two hoses i did not label are the lower radiator hose and the hose that runs from the bottom of my belch tank to the bottom of the radiator. All in all there are numerous places for air to get trapped and i need to figure out how to untrap it.

ShevrolayZ28

iTrader: (4)

Nice swap!

The 5/8" connection is the supply to the core, and the 3/4" is the return from the core.

The crossover tube is a good spot to bleed air, but if where it connects to the radiator is even higher, then you should be able to get the air out just by having the radiator cap off while it runs.

Are you sure you have a vacuum source connected to your heater controls? There's a vacuum nipple on the back of the intake manifold that you could use. I suppose it might be mechanical on an RX IDK.

joecar

The rear hose feeds the heater core, the front hose is the return. These straddle the bypass valve behind the thermostat, and air gets trapped in the heater core.

Yes, remove the hose from this crossover tube to bleed air out (may want to put a length of clear tube and point this into a clear bottle, this will clearly show air bubbles).


Fill the block and radiator with coolant via upper hose.

Remove the cap from your expansion tank.

Then with the crossover tube un-hosed for bleeding, start the engine and rev it to 2000 or so RPM every minute until the thermostat opens, observe what is being emitted from the crossover tube, when you see only coolant (flowing in the clear tube) then check if both heater hoses are equally hot, if they are, then you're done.

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Your upper and lower radiator hoses are on the same side of the radiator... are you sure this is going to work correctly (coolant is not going to flow across the radiator)...?