In mid-may of 2019, I bought a 1995 GMC K3500 4x4 ex-ambulance at a government auction near Portland, Or. Specifically, I bid on it, showed the listing to my future wife, was told it was too old and decrepit to buy. Then, unlike the dozen or so other ambulances I had bid on, I actually won the vehicle. So I flew down from Seattle, picked it up, and drove it back home that same day. It wasn’t the first truck I'd ever owned, but it was my first experience with a diesel, and it was by far the largest vehicle I had ever driven. Oh, and it has the infamous GM 6.5l turbodiesel engine, which is well known for being….underpowered. Especially when paired with a 5 ton vehicle. I'm creating this thread to document my buildout, as well as to get input about my design decisions.
Background
Tired of spending the majority of our lives working and living in a big city, spending ungodly amount of money on living expenses, and literally never being able to afford to buy a house where we live, my wife and I decided we wanted to move somewhere that we actually enjoyed living. We both grew up in a small mountain ski-resort town, and we wanted to regain that feel. Unfortunately, we haven’t had the chance to visit many small mountain towns, or even most of the western states that we were interested in living in - Colorado, Wyoming, Utah, etc. So we decided that we should take time off work, live in a vehicle, and travel around the U.S. to see where we wanted to settle down. After researching, I fell in love with the idea of converting a retired ambulance into a camper. I'm an engineer, so I have experience with 3D modelling and design, but I have limited experience in building or auto work, so I'm learning a lot as I go along.
Why an Ambulance?
I think the main ambo information thread covers the main benefits of an Ambulance. I considered old class B camper vans, small class C RV's, in-bed campers, fully custom boxes built on pickup chassis', and buying an LMTV with a box on it. Most of these options were eliminated due to cost; I wanted to keep the cost of the base vehicle under 8k, and the entire build under 15k. I was also leery of RV-style vehicles because I wasn't sure if the interior build would stand up to the punishment that fire roads can dish out. I was interested in an ambulance because of how well they're maintained, the higher GVWR of the chassis, and the high build quality of the box. Additionally, I was a fan of the fact that I could buy one within my budget, with a box on it ready to go. I looked at a 2001 E450 with 140K miles on it, and fell in love with all the size in the box. Unfortunately, the truck wouldn't start, even after they charged the batteries, and I learned that it had suffered from PMD-related electrical gremlins its entire life. I kept looking, and it took about 6 months before I finally won the govdeals auction for the ambulance I currently own.
Truck Details:
This is a 1995 GMC K3500, 4x4, Dually rear, 12,000 lb GVWR
Sticker Curb Weight: 10,370 lbs
Engine: GM 6.5l Turbodiesel, OBDI, Completely Stock
What's Broken:
- Front Brakes at 10%, mechanic recommended replacing calipers due diving right under heavy braking
- 4x4 system - Typical for this generation, the front diff actuator is dead. Will replace with 4x4 posi-lock
- A/C not blowing cold - Has refrigerant, compressor clutch engages when jumped. I suspect a faulty relay
- Engine Cooling - Temp climbs over 210 when climbing pass, on the freeway, on a hot day. Not the end of the world, but due to the limited power I would like to be able to push it without worrying about overhearing.
- Battery System - If left for more than a week both of the dual batteries die and the truck won't start. I'm going to install a battery isolator between the truck electrical and the box electrical.
- Steering: the steering feels loose and it wanders on the highway. Not sure why.
Intended Modifications to the Truck:
- PMD relocation kit - to keep the PMD alive
- Larger Radiator Fan - Improve Cooling
- Gauge Set - To be able to better monitor the truck
- New-style power mirrors - I would like to be able to move the mirrors from the drivers seat, as well as being able to fold them in when I'm in a tight parking spot
- Larger tires MT tires & possible Lift - I'm getting conflicting information about what size tires will fit on the truck with what size lifts. I'd like to fit the largest tires possible with the smallest lift possible, but it looks like its either a 4" or 6" lift, so not a lot of choices there
- A snorkel - Because it looks cool
- New Paint - so it doesn't look so ambulance-y
Box Build Out:
1) FloorPlan:
Kitchen in the front with sink, LPG stovetop, and dometic fridge in under-stove slide that stows in an existing exterior compartment. The countertop will use the existing counter space. Across from the kitchen, near the side door, the existing storage space will be gutted and converted into a tiny wet-bath. I'm conflicted between either a composting or a cassette toilet, but either way I'm throwing around the idea of mounting it to a slide so it can slide out of the shower when showering. The back of the box will be partially gutted so that a 6'-2" long permanent bed (double width?) can fit, mounted about halfway up so that storage is available underneath. A small dinette with sliding tabletop will be right in front of it, with enough room for two to eat or work. Much of the external storage will be preserved.
2) Heating:
Right now the plan is to implement a cheap chinese diesel heater. I'm struggling to decide between a forced-air vs hydronic heater. The initial price difference isn’t too bad, but the cost of supporting hardware for the hydronic really adds up, and the complexity increases as well. If hydronic, the heating system will consist of heater, underfloor heating lines, small water heater, exchange loop with engine loop to allow engine preheating. If I go with an air heater, it will just be ducted around the box, and an LPG instant water heater will be used for heating water. However I'm also considering adding in an air-to-water intercooler to allow me to still preheat the engine coolant, as I'm worried about cold starting this old diesel engine. It does have an electrical block heater, but I've read that the power draw is too great to run that off of batteries.
3) Cooling:
1-2 Maxxair fans will be installed, and I'm going to screen in all doors and opening windows to allow for maximum airflow.
4) LPG:
Honestly I haven't started designing this yet, I'd just like to do the following:
A permanently mounted tank under the box alongside the chassis rail. I'm not sure what size tank I need, or the best way to protect it from (off)road damage. The LPG will run the stovetop, possible the water heater, and the bbq/camp stove that will be housed on a slide in an external compartment.
5) Electrical:
(4-5) 100W Monocrystalline solar panels, linked to a MPPT solar controller, driving (2) 100 ah lithium batteries. A battery isolator will be installed to separate the truck batteries from the box electrical system. The batteries will power lights, fans, diesel heaters, water pump, fridge, phones, and laptops. I want excess solar panels to accommodate poor sun conditions, and ideally enough battery amperage for a few days, but realistically as much battery as I can afford.
6) Water:
(1) 40ish gallon tank will be placed horizontally just behind the bed divider. This places it centered left-right, and just in front of the rear axle. I'm worried about baffles though, is it necessary with this size tank? Would multiple smaller tanks be a better option? I don’t want to drop hundreds of dollars on a custom tank If it's not necessary, and I haven't been able to find much information on tank baffling. The tank will feed a 12v water pump, which will in turn feed the sink, shower, and water heater. The sink and shower will both drain to a gray water tank, although I'm not sure where it will be placed.
A picture of the current build state, to be updated semi-regularly:
