Land Rover Repair: cooling system, pin hole, gunk

Question
I have a 1997 land rover and I had a pin hole leak in my head that makes me lose antifreeze minimaly.  I added preston's radiator sealer and now my heat only works when I have rpms.  at idle it is cold.  Also my check engine light is on.  It is solid and not blinking though.  Can anyone let me know what is going on and what rout to go with it.  I am very capable of maintaining my own equipment but I am not familiar with rovers.

Answer
Hi Cory,

pin hole leak sounds ok but using rad sealer may have gunked up the system.  Flush it all out and start over.  If you're willing to manage the pinhole, don't add any aftermarket gunk that can cause all sorts of trouble elsewhere.

Eventually, you'll have to replace the head...no pinhole stays small for long.

Best of luck,

JohnMc