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Closed ?open cooling system????


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I am facing a delima I have a complete 97+ dash assembly and I will soon be graphtingit into my 87 Manche / Cheramanche. I am trying to understand the heating and cooling system. I think it should be pretty srtaight forward in the aspect of taking everything from a 97+ and swaping it over. But I need to understand better how a closed system compaired to an open system worksand if this appliesto what I am doing. I have noticed the 87 has a valve on the coolant lines and the 97+ goes straight into the cabin. If anyone has some info about this it will be a great help.

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As far as the heater goes there where 3 different type setups.

 

1) Renix Era w/vacuum controlled valve.

2) 90-96(ish) w/vacuum controlled valve.

3) 97+ with no valve.

 

If you are doing the conversion to an open system you will need to do either #2 or #3 above. The Renix valve won't work properly with the new open system.

 

When I did the conversion I opted for #2 above.

 

Here is a photo of the 90-96 valve. It can be purchased at the dealer for cheap and it's part number is 56005900.

 

100_1204.jpg

 

Also just for reference here is a photo of the Renix hoses vs. the 90-96 hoses.

 

100_1202.jpg

 

I just bought the new hoses, but I think with some creativity you could make the Renix hoses work with the new valve.

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So if I pull all of the heater and cooling lines out of a 97+ and use the 97+ heater assembly should everything go relatively smooth. I am setting myself up for a complete dash swap, so I already know that the old heater assembly won't work with the newer dash.

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So if I pull all of the heater and cooling lines out of a 97+ and use the 97+ heater assembly should everything go relatively smooth. I am setting myself up for a complete dash swap, so I already know that the old heater assembly won't work with the newer dash.

 

If you are swapping a 97+ dash, you won't have the vacuum line from the HVAC controls going to the water valve anyhow because there isn't one, so just use the 97+ hoses like so:

 

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The 1990 and below water pumps are different, but I don't see why not if the molded hoses fit as like mine. Heater core is the same. Or you could use ordinary heater hose, not the 97+ molded ones. Compare your's w. my pic and see it the water pump heater hose IN and OUT nipples are in the same location. Oh, and you have to block off the vacuum line that went to the water pump too. :D

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Besides the valve, there is also a door under the dash that diverts the airflow either through or around the heater core (or a mix of the two) to select temperature. I believe that door is there in everything from 1986 (84?) through current. So the vacuum valve can just be taken out of the system.

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