Welcome back for another Tech Note. This article is a bit different. Dan received a great question and decided to share the answer with you. Enjoy!
I have heard that a civilian H1 will ford water up to 30in deep. I see videos where the H1 has water going over the hood. What modifications are required for deep water fording other than the snorkel?
That is a very good question. First of all most of the military HMMWV’s are approved up to 30″. Some of the vehicles are approved up to 60″ with fording kits. The fording kit has a valve located by the drivers knee that shuts off the radiator fan and the vent to the wheel hubs, transmission and transfer case. The exhaust is extended up the left hand side of the vehicle. All of the electrical connectors are totally sealed and the engine does not have an ECM (Engine Control Module). The TCM (Transmission Control Module) is located in a water proof box to keep water out. A manual throttle is used so the driver can keep his head out of the water. The HMMWV is made to sink to maintain traction, so all drain holes are left open.
When AMG made the Hummer, creature comforts were added that should not get wet. This includes : upholstery, interior, electrical harnesses and connectors, radios, and Etc. I hope this answers your question. I have seen pictures of Hummers with water over the hood (I’ve been there) and this is usually for very short time. For example, crossing a stream or splashing in a puddle. It is a lot of fun.