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A few things I kinda learned...1. 997 heater core seems to always be active.. heat is controlled via mechanical flaps inside the evaporator. 2. These mechanical flaps tend to have leaks and the common disintegrated foam. 3. When the mechanical mixing flaps develop leaks the vents blow different temps...
For tropical countries like where i am. We seldom need heating. We always need cooling.. so after a few inquiries here regarding what could be, I jumped in and did it...
procedure: Battery removal is optional but it does make the work easier
1. Remove wiper cowl
2. Remove hose going into and out of heater core... try to do one at a time and quickly so as to minimize coolant loss
3. The loss in coolant is negligible and does not introduce air into the system.. there will be some decrease in level which can be topped of with distilled water
4. Install bypass pipe.. the tubes for the heater core are 3/4 in size.. buy 2 plugs for the heater core and the bypass hose for the inlet and outlet hoses...
The bypass line will have to go through the wiper cowl... finished product
Use a tie strap to tie the rubber bypass hose to the diagonal brace... that will be inside the cowl...
lastly test if the bypass hits the wiper arms...
My initial impressions:
1. Air temp seems to get colder faster
2. Cold air seems to be consistent with all the vents...
3. Cooling fans speeds seems to be lower...
I feel this will be beneficial for cars in tropical countries... also if the vent/mixing flaps are working properly and have no leaks, highly unlikely, this mod will have less noticeable benefits...
happy DIY,'ing all
Last edited by slicky rick; 09-01-2024 at 02:30 AM.
@Petza914 Pete, did you say you put a an electrically-operated valve on this coolant line in a 997? What parts did you use?
No, on a 928, which has a vacuum actuated heater control valve that cuts off or allows coolant to the core. The electric valve does the same thing but stays closed all the time when you want it to instead of opening when the vacuum relaxed from the engine being off.
Would it be worth the time to vacuum the coolant out of the heater core? Just musing as a guy who remembers cores developing leaks in older cars.
thats an idea. i kept the coolant in the core since i was thinking that there is some rust preventive chemical in the coolant that could help keep the heater in good condition just in case i want to use it, compaed to just having it exposed to the air.... really do not know, just a hunch
Would it be possible to simply connect the two hoses together? Is there enough play with the factory hoses?
Great job with the conversion. I would consider it but I still drive my cars in the cooler months, as long as there is no salt/snow.
there are 2 areas that we can do the bypass. one is where i placed it, the other is just really behind the battery. behind the battery there is a connection with the heater hoses and the aluminum pipe that travels from the engine to the frunk. you can actually place the U hose there too.
if your thinking of just using a straight connector to join the 2 hoses, the hoses would be too kinked to let the coolant still flow. the hoses are about a foot long each with particular bends. if you have a U-pipe connector, with both male ends then that would surely work... the parts i had were on hand so i decided to use them than buy new parts...
may i add that an aluminum U connector will surely work but it has to be the exact u shape that you can place it nicely.. otherwise the Ushape might be restricting in the placement..
Last edited by slicky rick; 09-02-2024 at 12:38 AM.
Did not want to interrupt the flow of coolant as it might affect something downstream. Was wondering why porsche did not put a heater valve there just like Pete's 928..????
Did not want to interrupt the flow of coolant as it might affect something downstream. Was wondering why porsche did not put a heater valve there just like Pete's 928..????
I suspect there are no issues with sealing that off. The reason I say this is that Porsche just controls the flow to the core by using a junction to a smaller pipe... what flows through to the heater core is what can fit given the pipe size and pressure it is pushing against. Cut it off and the flow through the main pipes increase a bit. Which, interestingly enough, may improve engine cooling a bit. But, if you want to be safe, keeping the loop is the way to go. Just guessing.
Peace
Bruce in Philly (now Atlanta)
Last edited by Bruce In Philly; 09-02-2024 at 04:56 PM.
I suspect there are no issues with sealing that off. The reason I say this is that Porsche just controls the flow to the core by using a junction to a smaller pipe... what flows through to the heater core is what can fit given the pipe size and pressure it is pushing against. Cut it off and the flow through the main pipes increase a bit. Which, interestingly enough, may improve engine cooling a bit. But, if you want to be safe, keeping the loop is the way to go. Just guessing.
Peace
Bruce in Philly (now Atlanta)
On this basis, removing the resistance of the heater core might divert more coolant through this bypass and reduce coolant to the motor???
09-01-2024, 02:27 AM
Diy: Heater core Bypass...for tropical countries
