Hello,
I just signed up with Honda Tech and was hoping to get some help with my daughters 2001 crv.

-Car has 98k miles,
-Check engine light came on 2 days ago
-Periodic idle fluctuations
-Periodic rough running when foot off accelarator pedal
-Computer test indicates idle air intake (or something related to idle not sure of exact code)
-Found no coolant in overflow reservoir
-Found white oily gunk on top of radiator fill cap and around cap itself

I took the car to a friend who works on hondas and accuras on the side and whose son is a tech at the honda dealership (i trust them and they have done some work previously on my sons accura) He ran the diagnostic test and got the idle error message. He called his son (who was still working at the dealership and ran through some checks (checking for signs of transmisssion oil leaks) He said that the white build up is oil in the cooling system which means a leak in the head gasket. He quoted me a price of $650.00 to replace the head gasket and send out the head to have it machined to ensure it does not have any cracks and the seal is good. I assumed that the radiator must be flushed and he said yes, did not ask about changing/flushing the oil or if any other work should be or needs to be done in the process.
Would like to know if his diagnosis is correct and if the price is good and if there is anything else which he overlooked.
Thanks in advance for any feedback