Cooling system overhaul

[lglade]

I think that heater cores and valves primarily fail due to corrosion issues which arise as a result of neglect of the cooling systems by Spider owners (previous owners--not us). Being sure to use the heater monthly (circulating the fluid) and keeping up with scheduled system maintenance should do wonders towards preventing similar problems in the future.

I've just finished the replacement of my own heater core and valve. My thermostat and water pump were both replaced last year when I did the timing belt. All the rubber coolant hoses are now new as well (the one to the overflow bottle was plugged, BTW). And now I'm going to make the conversion to a waterless coolant (Evans) to try to minimize future corrosion of the system.

[KevAndAndi]

If you have a flush T and you backflush the system, you should be able to get all the old coolant out without opening the engine drain port. Personally, I was afraid to open it for fear of stripping or breaking something and not being able to get it back on.

The block holds quite a bit of water. Draining it is necessary to completely evacuate the system. Then one can fill with the correct 50/50 mixture.

Without draining the block, you must add nearly 100% antifreeze/coolant to reach the desired concentration. But then you have city or well water instead of distilled water; not optimal.

Thanks, I stand corrected!

[aevansgatech]

I ordered the stainless short pipe for a clean install of the valve. That part makes sense to me now.

I do have one remaining question though. What exactly do I already have? I have the short and long heater hoses from AR, but are those meant for the dcfiat method or are they in fact the flex hoses that are meant to be on the engine side of the firewall (as shown in my picture)?

[baltobernie]

You're good to go with the hoses and pipe you have. The DC Fiats article was written prior to the invention of the new stainless pipe.

[DieselSpider]

I use distilled water and vinegar to flush as per the Engine Ice recommendation.

To fully evacuate the system I remove the thermostat and use a stainless steel shop vac regardless of what type of coolant I am going to use afterwards.