Radiator / Thermostat hose T-piece on the head - which way round does it fit?

[angello]

I'm working through a barrage of issues with my new to me '79 Spider.... one of which is the cooling system....
The cooling system has been woefully ignored over the years and I'm in the process of flushing and re-flushing, replacing pipes and generally giving it maintenance....

So far it looks like the heater matrix is dead, the thermostat has been 'gutted' and I'm wondering if the 'T-piece' on the front of the head has been reversed...

Which way round should that be?

Mine has been fitted with the restricted orifice facing the radiator top hose and the fully open orifice facing the thermostat .... which seems counter-intuitive .... I've looked on the parts diagram but it isn't clear from that which way it should be fitted.

It's number 18 in this diagram -

[TX82FIAT]

You may have the wrong part? Not sure, I know the carb cars have a different set up for that part without the bleed screw. However, the part you mention that hooks to the top of the head (#18) usually has a bleed screw that faces up to help let air out when filling the system. On the 79-85 the smaller orifice side is to the right when standing in front of the engine.

[angello]

Mine is a carb car... I do have the bleed port, but it's at a 45° angle in the bottom half of that T piece...

If I am standing in the front of the car looking at the engine (imagine the bonnet removed) and looking at the front of the engine, the T-piece has the restricted orifice facing towards the RIGHT (i.e. drivers side of LHD car) with the rubber pipe connected between the restricted port and the top of the radiator.... The un-restricted port of the T-piece faces towards the LEFT with the rubber pipe connected to the thermostat T-housing....

Does that sound right?

So the restricted port on the T-piece is limiting flow through the radiator?

[TX82FIAT]

Well, now you have me second guessing myself as the bleed screw should be facing slightly up in order to be a bleed screw to be effective. On the FI cars the bleed screw is on top and the temp sensor is below that. I've attached a picture of a 79 t oulet to see if that helps.
unless

[Nut124]

Common sense would say the restriction should be towards the water pump. This is how the fluid flows when the engine is cold. The restriction maybe there to provide some backpressure so the cabin heater would flow/work if needed.

When the engine is hot, coolant flows from the head to the top of the radiator and any restriction would hurt cooling.

[Odoyle]

On my 77, 79, and 83, the restricted side of the t is facing the exhaust side (thermostat side) and the fully open port connects to the radiator.

[angello]

Well, now you have me second guessing myself as the bleed screw should be facing slightly up in order to be a bleed screw to be effective. On the FI cars the bleed screw is on top and the temp sensor is below that. I've attached a picture of a 79 t oulet to see if that helps.

I have the exact same bleed screw as the one I can see in your picture, but mine is on the bottom.....

Common sense would say the restriction should be towards the water pump. This is how the fluid flows when the engine is cold. The restriction maybe there to provide some backpressure so the cabin heater would flow/work if needed.

When the engine is hot, coolant flows from the head to the top of the radiator and any restriction would hurt cooling.

That was my feeling - common sense suggests there shouldn't be any restriction towards the radiator.... That's why I have queried it.

On my 77, 79, and 83, the restricted side of the t is facing the exhaust side (thermostat side) and the fully open port connects to the radiator.

That's extremely useful, thank you. I think based on what you posted and the other posts above my car has it's T-piece fitted upside down and the restriction is facing the wrong way..... I'm going to whip that off and re-fit it the other way up. Hopefully that will help restore my cooling system to better functionality....