Bleeding cooling system on a Cayman

[milleman]

Can anyone offer any advice on how to bleed the cooling system on a cayman?

[Rockster]

milleman said:

Can anyone offer any advice on how to bleed the cooling system on a cayman?

There are two ways. First is to run engine at idle or fast idle until coolant gets hot enough to cause t-stat to open and coolant to flow through out the system. Add coolant at the tank until the level no longer drops after some idling. Some references direct one to raise the engine rpms to IIRC 5K to really get the engine/cooling system hot.

The 2nd way is to buy a special tool (vacuum pump -- here in the USA Snap-ON makes some: mityvac IIRC) designed specifically for cooling system bleeding/refilling. One uses this tool to pull a vacuum in the cooling system -- when my Boxster treated to this at a dealer (OPC) the vacuum (pressure diff) was enough that the coolant hoses collapsed. Once the system has a good vacuum (real low pressure compared to atmospheric) the vacuum line to the pump is closed and the line that runs over to a tank/reservior of pre-mixed coolant is opened. This tank/reservior is open to atmosphere so the air pressure forces coolant out of the tank into the coolant tank of the car and into the cooling system.

Doing it this way almost always fills the system completely with coolant sans no air pockets without the need to race the engine at an elevated rpm level like I described in the first method above.

Sincerely,

Rockster.