September 30, 2012

The 1999 GMC Suburban 6.5L Turbo Diesel, my new Cold War camping vehicle

Someone's head will explode when they read this, but the Bombardier Iltis may not be the perfect vehicle for my Cold War tourism hobby.  Let me compare, contrast, and explain what I've figured out.  I've taken three different vehicles to various Cold War sites across Canada.

In August 2011 I drove from Carp, ON to Parent, QC in a 2003 Pontiac Grand Prix.  The Grand Prix is a 205HP Front-wheel-drive 4 door sedan.  Travelling with one passenger (DA), and a ton of camping gear, was extremely comfortable, and we only spun out in a torrential downpour on a dirt road once - no damage.  The road between Carp and Parent was paved for the first half, and dirt for the 2nd half - there was never any fear of getting stuck or being unable to take the vehicle anywhere.  It even went up to the operations site of the former RCAF Station Parent.   Overall I didn't regret taking the car, there wasn't anywhere I didn't go because of it, but with a more capable off-road vehicle we would have gone to more/other locations I think.

In the March or April of 2012 I drove from Carp to Foymount in the Iltis, and had a great time.  The ride was smooth, most of the road was paved, the day was sunny but chilly, and I didn't get filthy.  The trip wasn't very long either - there and back in a day.  This confirmed to me that the Iltis was an awesome drive-anywhere vehicle.

In April of 2012 I drove from Ottawa to Parent again, this time with friends.  Carp to Parent is a much longer drive.  It had snowed heavily the day before (and during) our trip.  Capability wise the Iltis got stuck offroad only once, and used it's own winch to get out of the spot it was in.  I was able to take the Iltis anywhere and everywhere, and this time I crossed terrain that would have obliterated the Grand Prix.  To get from the town of Casey to the airstrip at Casey required a vehicle that had better approach and departure angles than the Grand Prix - by a long shot.  The Subuaru we were with barely made it (AWD was great, but angles were a problem in one spot), the Jeep Liberty performed well, and the 2WD Dodge Ram did OK (it may or may not have made it to the Casey Air Strip, we didn't attempt it)  Off-road/On-road the Iltis showed it could go anywhere... However...
All items in the Iltis were filthy by the end of the trip, we had the rear plastic window rolled up, and everything was either covered in dirt, snow, or both - mud.
All passengers in the Iltis were cold, wet, or both.
We were travelling with the doors on, because of the cold weather; else we would have been colder, dirtier, and wetter.

In August of 2012 I drove from Carp to Oba, ON via Hornepayne, ON first along HWY11 and then back along HWY17.  Part of the trip I had a passenger (RH), and I was driving the aforementioned Dodge Ram 1500 2WD regular cab pick-up.  Along this trip I was conscious that I wasn't driving the Iltis, and I wanted to question myself whenever I did something in or with the Ram; IF I was driving the Iltis, would I do this?  If not, what would I lose/gain from using the Iltis?  The results of this self-questioning were somewhat sobering.  The drive to Oba was ~16Hrs, and the drive back seemed longer - perhaps because I was already exhausted from getting there, and had naps on the side of the road along the way home.  That's the first tell; if I was driving the Iltis I wouldn't be napping IN the Iltis, it's too uncomfortable.  The interior of the Dodge Ram was leather, and has a bench/captain's chairs - when not travelling with a passenger, LOTS of room to nap.  My passenger was also heat/cold sensitive; if I'd taken the Iltis they would have died, I'm sure of it.  The Dodge didn't fare as well as the Iltis would have in the rough terrain, BUT the Dodge didn't get stuck - to be fair - I didn't put it at risk of getting stuck either.  Another surprise was the tonneau cover on the back of the short box Dodge Ram wasn't sealed enough to keep the dust off the camping gear.  By the end of the weekend, everything in the pickup truck bed was covered in road dust.  The whole reason I didn't bring the Iltis was because the rear differential went, and I haven't bought or installed a new one.  Gas mileage on the Dodge Ram with it's 5.9L Magnum engine is poor, but after driving thousands of kilometres, it got down to 15.4L/100km.  I would have wanted, in hindsight, to have a 4WD extended cab pickup, Jeep, or SUV; I would have been able to go more places, with better piece of mind, still napped in comfort, and not got everything filthy.  But how to decrease my gas consumption?  Diesel?  4Cyl of 6Cyl gas engine?  Maybe just a new modern engine (A Dodge HEMI is far superior to the Magnum when it comes to horsepower AND fuel economy...)?

I contemplated and studied the obstacles and my lessons learned.  I came up with a solution.  The GM Suburban, Tahoe or Yukon (Chevy or GMC, long or short) in 4WD, Diesel and with leather would be the target.  Unfortunately, there are precious few of those on the road, let alone for sale in Ontario (or anywhere else).
Let's review the pros and cons...
  • GM Vehicles in general do not have a great reliability history, but, they're predictable, well known by all mechanics across North America and the parts are plentiful.  This is not true for the Iltis.
  • The vehicle comes in leather, that's a feature I won't compromise on.
  • The vehicles comes with 4WD, again, that's something I won't compromise on.
  • The vehicle can be kept clean on the inside (no dirt/dust)
  • The vehicle has amazing cargo room, and the possibility to mount additional aftermarket roof racks.
  • Diesel is an option, and the 6.5L "Detroit" Turbo Diesel is not the most powerful Diesel in the market, but delivers respectable fuel economy.
  • It has a 158L diesel gas tank.  Yes, 158L.  It should be able to go over 1200 highway kilometres before a fill-up.
  • The vehicle can realistically be kept warm, it doesn't have canvas or vinyl sides, and should warm up comfortably after hours on the road.
So I dropped the hammer, and after three tries, got a seller via Kijiji to actually SELL me a 1999 GMC Suburban... I bought one.  It isn't precisely what I wanted; the gears are 4.10 rather than 3.42, but it will do!  All the other features are right in line with what I wanted.  It should be more fuel efficient than the Dodge Ram, capable enough with 4WD, and have enough space to bring everything AND the kitchen sink.  I'm very excited to take it to Belleterre, Val D'Or, and Senneterre in the coming weeks.  Reviewing the popular industry magazines, the Suburban is in the top 10 best "road trip" vehicles with good reason, and the '99 places better than the Excursion, Yukon and Expedition for overall ride, comfort and performance.  I'm looking forward to the next outing to give my own opinions on the 1999 Diesel Suburban :)

1999 GMC Suburban 2500 4WD
6.5L Turbo Diesel (L65)
190 HP @ 3400 RPM
385 ftlb @ 1800 RPM
4.10 Axle Ratio
7,500 lb Towing Capacity
GM 4L80-E Transmission
158L Fuel Tank
Goodyear Wrangler AT/S
P245/75R16 tires
Exterior: Pewter Metallic
Interior: Light Grey Smoke with Grey Leather


  1. So what is happening with the Iltis? Selling it or keeping it for short trips/off road fun?

    1. I'm sorry to see them go, but I'm selling the "main" one, and the two others that could be fixed up to be off-road-worthy, or just used for parts. It would be a shame to part them out since they all run; the two "spares" don't have good clutches, but I have two spare clutches that could go into them. The listing is on Kijiji (Ottawa)

      Let me know if you're interested!

      As I explained it to a friend of mine yesterday; they're the ultimate road-driveable-ATV... but I don't need an ATV... They're far superior to those side-by-side ATVs which have taken off recently, IMHO.

    2. I'd look into shipping the whole kit in a shipping container, if you're interested...

  2. Indeed it is a shame to see you selling them! I'm in Regina, Sask. and recently bought an Iltis for myself and am fixing it up. Runs great now after I cleaned the entire fuel system and replaced the carburetor with a new one (out of Alberta... was cheaper then getting a rebuild kit and much faster). I should thank you for your blog items on the fuel system since I used them a guide to figure out my running problems and to pull the gas tank.

    If I could ask for a favor (I'm good for it I swear!) could you please take some closeup shots of how the former owner installed the winch? I'm thinking of mounting one myself since I off-road alone a lot... plus is it a handy item to have. I just need to find a 24 volt winch now or figure out a way to charge a separate 12 volt battery in the wheel well.

    pics can be sent to

    Thank you!

  3. I have a 1999 GMC Suburban almost exactly like this one. Mine has cargo/panel doors, 6.5L, gray leather, 4WD, and 53,000 miles. It was in storage for about five years and even the factory paint looks like new. I'm curious as to your fuel economy on the highway and around town with that 4.10 axle - in an effort to improve my own, I replaced the wheels/tires with 20-inch 8-bolt rims mounted with Goodyear Wranglers. The overall tire diameter is now 32.5-inches vs the factory 30.5. Now when I'm driving 75 MPH indicated my actual speed is about 81 MPH - The tires have been mounted on the vehicle for about a week. Next I'll try to re-gear/re-calibrate the speedometer in a few days once I figure out how and calculate exactly what gear I'll need to do that with - and find a source for the parts. I'm not certain what axle ratio mine has, but it "feels" like a 3.42.

    1. Is yours the 2500 or 1500? The RPO codes in your glove box will tell you the exact ratio it came with from the factory - I can't even tell you waht my MPG is right now because the turbo is misbehaving :) I still love this beast, even with all the issues. If you haven't, relocate your PMD immediately with a kit from SSDiesel, it *will* overheat where it is, mounted by the pump! If your exhaust goes, go for the kit from SSDiesel too, it's fantastic! I went with the "medium"-loud exhaust, it's pretty loud - if you have neighbors you might want the quiet one :)