I"ve had alot of these vehicles do this, they have air in the cooling sys. Try this bleeding procedure:Poor heat at idle, however, if the engine RPMs are raised the concern no longer occurs.
Note: Be sure to follow all SI safety procedures and caution notices.
With the engine cooled off, remove the coolant pressure cap.
Remove upper heater core hose from the metal pipe on the engine.
Add coolant to the metal pipe, until full.
Raise the rubber portion of the heater core hose as high as it will go with it still attached at the heater core. Using a funnel, add coolant until the hose is full.
Reconnect the heater core hose.
Start engine, have assistant raise the RPMs to about 1500 to 1700 RPMs, top coolant off at engine, then before lowering engine RPMs, install the coolant pressure cap.
Fill coolant reservoir as necessary, then check the heat at idle.
Note: If the vehicle returns for the same complaint perform the cooling system draining and refilling procedure
see if this makes a difference, post back with any other questions.
Monday, February 12th, 2018 AT 2:28 PM