KTM came out with the XC-4 500cc motor in 2008, characterized by putting the engine and gearbox in separate oiling chambers. There were a lot of running changes and improvements to the motor in the subsequent years. Thus 2011 parts for the same XC-4 motor are desirable in a 2008.
The oil pump shaft, gears, and main oiling jet can be upgraded with new OEM parts.
Finally resolved the oil migration issue on the 2008 KTM 530 EXC, the first year of the XC-4 motor that contained separate motor oil and gearbox oil compartments.
The bike’s factory breathers is a closed system connecting the crankcase from the valve cover, the gearbox, and the air intake after the filter.
Oil migration was happening out of the crank case breather, which is connected to the top of the valve cover. Visible through clear breather tubes, there was oil in the tubes leading to both the intake and gearbox. No telling at what ratio, but enough to require topping off the engine from half, as viewed through the sight glass; equivalent to a few ounces, every few hours.
The kickstarter lever, on the right hand side of the bike, has an idler gear accessible under the clutch basket and located directly under the gearbox breather. It’s a known issue that the oiling holes are found to be misaligned.
Indeed my bike had misaligned oiling holes, and thus rectified the issue by extracting the bearing bushing and reassembling in the correct oiling hole alignment.
Used an appropriately sized socket and hammer to drive the bushing out.
General Motors built the Hummer H2 generation with cast aluminum, 17×8.5 factory wheels. With an 8×6.5″ bolt pattern, the rims are compatible with OBS Ford and early 8 lug 3/4 and 1 ton American trucks. However, the center bore does not fit over the 2nd gen Dodge unit bearing hub flange without modification.
To modify the rim, simply open the rim center radius by roughly 1/8″ of an inch, or a total inner diameter increase of about 1/4″.
Factory H2 wheel design is a 7 spoke, cast aluminum 17″ rim with 5″ of back spacing. It opens up the possibility of running late model 17″ Load Range E tires.
Attempted to modify the rim by using a router tool and 2-flute routing bit with carbide inserts. Worked well for routing by hand.
The inverted-y steering and front end of the 2nd gen Dodge 4×4 truck, tasked with suspending the heavy duty Cummins motor, needed a major refreshing. Even with a solid front Dana 60 axle and stock ride height, the tie rod ends and trackbar in the suspension were clearly tired.
Took the opportunity to replace all the steering and drag link, tie rod ends, and trackbar with greaseable Moog units. The factory trackbar design on the 2nd gen is an upper tie rod end to a bracket on the driver’s side frame rail, and a lower bushing end bolted to the axle. Worn or loose trackbars are notorious for causing steering death wobble.
In addition to refreshing the steering, also added a steering box brace by BD Diesel, which spans the frame rails and captures the steering box sector shaft in double shear with a pillow block bearing. The brace bolts to the frame under the factory sway bar mounts, so went ahead and replaced the oil and diesel soaked bushings with new Moog rubber. Lastly, wrapped up with a laser alignment to set toe angle.
1994-2002 Dodge 4×4 trucks with the front Dana 60 use a vacuum actuated CAD: center axle disconnect. The system relies on a gear driven vacuum pump off the Cummins motor and plastic tubing leading to the external diaphragm and actuator in the passenger side axle tube, next to the low pinion differential. Inside the CAD assembly is a shift fork that slides a splined collar to engage and disengage the 2 inner axle shafts.
For a truck with cracked or leaking vacuum lines under the hood, the CAD does not engage (incidentally along with related HVAC mode selector), which then prevents the powertrain from reaching the front axle. Also, the open vacuum system will indicate an erroneous 4×4 engagement on the dashboard even with the transfer case in 2wd.
To resolve, added a 4x4Posi-Lok manual cable to engage the shift fork in the CAD housing. The benefit is firstly the manual actuation independent of the vacuum system, and secondly the ability to manually disengage even in 4×4 low range, to run 2wd in low range (similar to running a manual locking front hub axle unlocked in 4×4 low range).
Installation requires routing the thick actuator cable through the firewall and down to the axle housing. The diaphragm and factory CAD cover is eliminated in place of a new cover to reuse the fork and accept the push-pull cable, which then mounts to a bracket in the cockpit below the dash. Also took the opportunity to service and change front differential fluid.
Truck overheated on a cool winter, late afternoon, while crawling up a hill in snarling Los Angeles traffic. Was slowly inching alongside a highway detour to bypass a wreck as it poured cats and dogs from the atmospheric river before Christmas 2021.
As I crested the hilltop, noticed a late model Dodge truck pulled over on the shoulder with its hood up, steam billowing out like a geyser. Ouch, I thought, that’ll slow down their journey. That’s when I glanced down at my own temperature gauge and saw the needle pinned in the read at 230*F !?
Immediately pulled over and shut the 12 valve Cummins down. What’s going on? The cooling system on the relatively new to me truck hadn’t yet been gone through, as it hadn’t exhibited any major problems.
Although, it did once spit out some coolant from the passenger side lower vent and onto the transmission tunnel carpet, months ago when first test driving and taking delivery of the truck from the desert. Coolant would never came out again. That indicated a heater core, so early on procured a replacement unit but was certainly not looking forward to the invasive procedure under the brittle dash to reach it. The original dash lived under a felt pad and was miraculously intact save a single crank.
Along with anticipating a heater core and the imminent day I’d open up the coolant system, had also procured a Cummins 180*F thermostat, Gates water pump, and 6 gallons of Zerex diesel coolant , the premixed red solution.
Prior preventative on the motor was simply a new radiator cap and fan clutch as the original would not spin freely by hand.
Waiting for the truck to cool on the side of the road from an overheat would take ages. So I flipped on my white & amber light bar to strobe over the cab and coasted down the shoulder at engine idle speed to get some air flow over the radiator, merged back into traffic all while willing the head gasket to hold together.
The temperature gauge still would not come out of the red, so in order to ram more air over the radiator, hooked a right at the end of the road and into the direction of reverse traffic. The motor finally started to cool as the truck got up to speed and I dropped the transmission into neutral to bring the RPMs down to idle while coasting.
Likely a sticking thermostat, at the most inopportune time on a trip before the Christmas holiday and hundreds of miles away from home in weather!
Made it home in the middle of the night after avoiding further gridlock traffic and without further temperature spikes. No evidence of water in motor oil, nor oil in coolant. Now to diagnose.
First, started with a coolant flush by uncorking the radiator petcock and draining out the very dark green fluid. Next, added a coolant system detergent and topped off with distilled water to begin flushing process. The cooling system for the 12 valve takes a total of 6 gallons including reservoir capacity, and about 3 gallons come out at a time from the petcock with closed thermostat.
Upon 2 cycles of flushing and topping with distilled water, both test drives on the freeway exhibited erratic temperature where it would climb to 200*F on its way to overheating, then the thermostat would finally open and drop the temp to normal 180*F operating temp. Happened at exactly the same freeway exit both times so exhibiting consistent behavior.
Next, by passed the heater core by taking one of the 5/8″ ID heat hoses to the firewall and creating a u-turn back to the motor. The truck still continued to show erratic temperature.
Finally, time to break the seal on the thermostat housing and get to the likely root cause. Thankfully on the 12 valve Cummins it is relatively easy to get to, requiring removing the accessory belt, unbolting and loosening the alternator bracket to pivot it out of the way, and 3 bolts that fasten the thermostat housing.
The intent now is to isolate and test the thermostat in boiling water, and continue to flush the system now completely open without a thermstat.
Interesting how the flushing drastically changed color once rust tinted water from the cast iron block is drained, as opposed to only from the aluminum radiator.
To test the thermostat and verify it sticking, simply boiled a pot of water on the stove and used a pyrometer to measure when the thermostat was in fact opening. Turns out it indeed didn’t open until over 200*F.
Continued flushing the open coolant system with water and detergent. The diesel motor certainly does not like starting after sitting all night in the 30’s*F temperature, and of course will not warm up without a thermostat even on surface streets.
Took the opportunity to also verify the new thermostat, rated to open at 180*F, indeed operates normally with the stovetop boil test. Final phase of flushing was to use a garden hose and flush the radiator with lower hose disconnected, and also open the petcock drain and poke it clear of any debris; then likewise flush into the motor from the upper hose.
Wrapped up the resolution by installing the new thermostat and seals, reconnected the heater core with new hose, topped off the coolant, and recycled used engine coolant at a proper disposal facility.
1997 Dodge Ram 2500 4×4 5.9L 12 valve Cummins intercooled turbo diesel, extended (club, sail B-pillars and non suicide doors) cab long bed, 47RE 4spd automatic transmission, ball joint Dana 60 front axle, NP241 t-case, Dana 70 rear axle and 3.55 gears. Fleet truck white with a lined long box interior.
Drove this 2nd gen Cummins home the 450 miles from Death Valley, where it spent at least the past 10 years as a work truck on a desert resort property, hauling heavy trailer loads and campers. The previous owner has since moved on to 3500’s and up.
Needs some TLC and a thorough mechanical baseline. I like to get to know my rigs and touch all the systems this way. Here’s how I get down my first Cummins turbo diesel, a 12 valve 5.9 liter inline 6. I start under the hood, and then pull each wheel to service every corner of the truck.
Before we even begin, right away, initial accolade is mad respect, for this is the first vehicle that has made it from Death Valley to the SF Bay Area on a single tank of fuel, as taken delivery of. 35 gallon capacity this truck
Started with a basic oil change, using a blend of 10 quarts of 15W-40 Motorcraft plus 1 quart of 5W-40 Rotella T6, and a WIX oil filter. Interesting to note that a 12 valve Cummins only takes 11 quarts of oil, compared to the 7.3L Powerstroke that requires 15 quarts. I have found that the Cummins 12v warms up and reaches operating temperature way faster than the 7.3L Powerstroke. Waaay faster.
Next up, WIX fuel filter and 3 new o-rings for the canister filtration system, and learning to prime the P-pump fuel system using the air plunger attached to the lift pump.
Upon taking out the unknown fuel filter that came with the truck, and am taking precautions to treat algae and microbes in the fuel system with Biobor JF Diesel Biocide and Lubricity Additive. 1 fluid ounce treats and ‘shocks’ 40 gallons of diesel.
The 2nd gen Rams are set up with a single tank of fuel, 32 gallons capacity according to the owners manual. I often run HPDE B20 which is a 20% biodiesel blend by Propel Fuels.
With a fuel pickup all the way down to the bottom of the tank, the top ranges based on MPG averages:
32 gal tank @ 20mpg = 640 miles (1030km) range maximum
32 gal tank @ 15mpg = 480 miles
32gal tank @ 12mpg = 384 miles
32gal tank @ 9 mpg = 288 miles range (460km) range maximums
Front unit bearings and disc brakes
On to the front axle, replaced front hubs the Dana 60 with MOOG unit bearings. These are similar to what are found on late model jeeps and 4x4s that do not have a manual locking hub (which is more common on Ford drivelines) and instead use vacuum actuation.
Front wheel hubs bolt to the outer knuckle of the truck’s Dana 60, using a total of 4 M14x1.5 bolts. Previous owner had indicated the passenger side bearing seems to require more attention, which upon replacing, discovered was loosely attached with only 3 of 4 bolts. Note, the thread pitch is strikingly similar to the English tread 9/16″-18 used for wheel studs, yet are not to be interchanged. The factory bolts are 12pt and 14mm socket fits well; the replacements are 6pt hex also 14mm.
Coming from the high pinion Dana 60 (hpD60) balljoint axle with manual locking hubs used on the OBS Ford, I’ll have to take the Dodge version on the trail to evaluate my preference.
It seems possible to swap outer knuckles at the u-joint, so the Dodge can run a set of manual locking hubs, instead of relying on only the 4×4 Posi-Lok cable actuation.
On the new XC-4 motors that KTM introduced in 2008, it was found the water pump seal was installed backwards from the factory, with the spring oriented in the wrong direction. It seals, but eventually fails.
My pump developed a leak shortly after a week of King of the Hammers 2021. x hours and x miles
To access the seal,
Remove the water pump cover bolts 8mm and cover to expose the impeller
Remove the impeller bolt 10mm
Pry off the impeller and spacer
Now the water pump seal will be visible, and if installed backwards, the spring will be pointed towards the engine and out of view.
To remove the seal, force compressed air up the weep hole to pop out the seal.