Do y'all have any suggestions on what to do about the flywheel? TPWS said they look at the condition of the existing one and decide if it needs to be replaced. What's the reliability of dual mass flywheels on these cars? My car has 98k on it. It's $900 to replace it.

 

In my case, previous owner changed it together with clutch as seems that it was damaged. I read in other posts that it is usually replaced “every other clutch”; but I guess that depends, I’m not sure, but should at least be resurfaced if it is intended to be re-used (and sometimes this is a debatable field). A good Indy will tell you (and show it) why is needed (or not) but can find that is scored and need replacement. For the invoices that I got with the car, the dealer at that moment (Porsche Atlanta) put OE genuine Porsche parts but I heard that Sachs (OEM) is very good quality kit too. That was 25k miles (5yrs) ago. And yes, the flywell is expensive, specially if it is genuine OE. Just shop around it shoul go for OE between 1.4k and 1.9k. Very hard to find an OEM supplier for the flywheel so the price quoted seems that isn’t bad (if needed).

 

I didn't get any service records with the car so I don't know if the flywheel was replaced before. I'm tempted to have it done whether they say it needs it or not because I don't want the flywheel to fail in 10-20k and have to go back in.

 

Dumb question but does anyone have a link to a low temp thermostat? Can you get an OEM one?

 

Pick the right one for your generation

https://lnengineering.com/catalogsea...ostat+low+temp

 

What's the consensus on this kit?

https://lnengineering.com/porsche-oe...riven-csp.html

Is the coolant additive worth it? This is the water pump to use right, not one with metal?

 

That’s what I used, had everything you need minus coolant. I can’t remember if I dumped in the water wetter or whatever it is or not. The impeller is not metal as notes in the description. LN is a reputable vendor, and a safe source in my opinion.

Edit: I did buy some sort of gasket glue to hold the gasket in place while fiddling with it during the install, so that wasn’t included.

 

Yep, that's what you need. Have never used the coolant additive, but love Driven stuff so may look into it. Yes on the composite impeller - never metal.

 

I also used the kit, but you'll need to source coolant separately.

 

@Petza914, just curious why one should avoid using a water pump with a metal impeller? It would seem to be a more robust solution, but I am far from educated on the nuances.

Thanks!
Bob

 

What usually causes water pump failure is wear in the shaft bearing to the point that the tension from the belt on the pulley causes enough impeller shaft deflection that the seal around the shaft starts to leak. For a water pump to pump efficiently, the cavity the impeller spins in has a tight tolerance to the impeller. With a metal impeller, as the shaft angle deflects from square, a metal impeller on the end of that shaft can start contacting the block cavity and milling the metal away, whereas a composite impeller has it's fins gradually worn away as the angle and contact increases as the bearing wears. Once the cavity in the block is deformed, even when a new pump is installed, because the cavity isn't perfectly shaped for the impeller anymore, the pumping efficiency will be reduced.

 

Awesome. Makes perfect sense.

Thanks @Petza914 .

Bob

 

I've got a new mechanic who has cautioned me to stay away from a low temp thermostat and instead to use an OEM one. He said Porsche has an updated version. Is that ok? Should I be concerned? Everything else he's said has been spot on.

 

Did they explain reasoning behind avoiding the low temp thermostat?

 

If you have a 997.1 you want a 160 degree low temp thermostat. You need one that opens earlier then the OEM 180 degree one so the engine warms more gradually. Can't think of any way a new, redesigned one can be an improvement unless it also opens sooner, which means it too is a low temp thermostat.

Your mechanic may not understand the reasons behind this. Only downside i can envision is if you live where it's really cold and the thermostat opening at 160 is going to prevent the engine from ever reaching proper operating temperature, but since.bore scoring is more prevalent in cold climate cars, odds are you'll end up with it anyway if staying with the OEM 180 thermostat.

....So in a nutshell, no, not OK.