You said it. Weatherpac connections are designed to resist moisture, not direct high pressure spray.

The ICP plug is very susceptible to moisture, given it's location with the backside pointed up from the top of the head, and has been the cause of many engine washing malady's on this site.....water in the ICP will cause it to run something like troutnut1 described.

 

I washed mine cold with a couple of cans of that Gunk stuff and a garden hose. Not sure if it was a coincidense or not but when I drove the truck for the first time my water temp sensor on the head decided to pick that exact time to turn on the light which tells me my engine is overheating while the gauge said everything was fine. When I checked the sensor by putting it in a pan of hot water to check the resistance water began to bubble out of where the metal meets the plastic on the sensor. I'm not so sure I'd be so quick to wash my engine again....what a headache!!!

Here's something else I found odd. I called the dealer and priced a new sensor and I believe they quoted a price of around $60 but what else could I do. When I got there he asked if this was for a business and I say no so he makes one up and sells it to me for around $23. I was very appreciative but what's with that??? Oh, and it did solve my problem.

Jeff

 

Jeff -
Dealerships sometimes have discounts worked out with auto repair businesses. If you have to get a big ticket dealer only item, it is good to have a friend in the auto repair business...