The heads have to come off anyway so run them over to a local machine shop and have them cleaned, magnafluxed, and milled. The cost is suprisingly reasonable. Now is the time to change the water pump and thermostat. The worst part of this job is the sore back due to the design of the engine bay on the van. Good luck, let us know how it goes.

I will exactly that and keep you up to date on progress. Again, many thanks.

As an update. This is the report that I got from the dealer.
"Ran vehicle and waited for cooling fan to come on, fans came on a 107 degrees C. Checked for engine codes. Code P0300 - Engine misfire detected. Pressure tested fluid system and found leaks at water pump and cooling pipe coming out of intake. Recommendation - both head gaskets, send head out for inspection. Replace water pump, coolant pipe, coolant flush, thermostat and engine shampoo.
Anyone know if these are all signs or indications of the head gaskets. Please take into account that there was apparently no suggestions as to why this is happening in cool weather and it ran through one of the hottest summers that we have had with no problems.

Thanks

its hard to have a misfire unless you either have bad intake gaskets or head gaskets. once you are at the intake you might as well take the heads off too. i would probably do everything they were talking about. i think they have a gasket kit that has the redesigned gaskets, for the intake man. that pipe went on my car too were the pipe makes a 90. i just put some jb weld on there and sprayed it black again, never had another issue.