1985 Autocar: we work on any truck
If it runs diesel and needs help, we'll show up. Age is not a barrier: classic, vintage, or modern.
Diesel RV & Motorhome Repair
Mobile Diesel RV & Motorhome Repair in Charleston, SC
Diesel pusher throwing a check engine light at the campground, or a Super C that won't crank in the storage lot? We diagnose and repair the diesel engine and chassis where your motorhome is parked, so you are not arranging a tow to a shop.
- Cummins and Cat diesels, Allison transmissions, air brakes, chassis electrical
- On-site at campgrounds, RV storage lots and driveways
- Charleston, North Charleston, Summerville, Goose Creek, Mount Pleasant
Diesel Motorhomes We Service
Diesel pushers, Super Cs and the drivetrains under them
Diesel pusher chassis
Freightliner Custom Chassis, built in Gaffney, SC, and Spartan RV Chassis, now part of Aebi Schmidt Group after its 2025 merger with The Shyft Group. Older Blue Bird Wanderlodge pushers too.
Super C and Class C diesels
Super C coaches built on the Ford F-550 Super Duty and Freightliner M2 106 truck chassis.
Diesel engines
Cummins ISB, ISC, ISL and X12 engines, plus the Caterpillar 3126E and C7 found in pushers built before Cat left the on-highway engine market in 2010.
Allison transmissions
Most diesel pushers use an Allison 3000 series automatic. We read transmission codes, check fluid, service filters and chase shift complaints.
Engine And Chassis Only
We fix what moves the coach, not the house
A diesel motorhome is a truck chassis with a house built on top. We are diesel mechanics, so we work on the truck side: engine, cooling, fuel, aftertreatment, transmission, air brakes, chassis batteries and wiring. We do not repair coach appliances, plumbing, slide-outs, awnings or roofs. For those, an RV technician is the right call.
Founder and lead technician Joseph Cufaude has 13 years in the diesel trade. We test with codes and live data first, then replace the part that actually failed.
Why RV owners call us
- Service at the campground, storage lot or driveway
- Testing before parts replacement
- Clear written findings and next steps
- Diesel engine and chassis focused
- 24/7 Charleston-area availability
Common Diesel Motorhome Work
Problems we handle on diesel RVs
DPF and DEF faults
Engines built for 2007 and later use a DPF, and 2010 and later add SCR with DEF. Coaches that sit or make short runs load up the filter. We diagnose, run parked regens and offer DPF cleaning.
Rear radiator overheating
On a pusher the fan pulls air across a hot engine bay into the rear radiator and charge air cooler, so dirt and oily crankcase vapor coat the fins. We check the fan, stack and pressure.
No-starts and batteries
Months in storage drain chassis batteries. We test batteries, cables, grounds, the starter and charging system before anything gets replaced.
Oil and filter service
Engine oil, fuel filters and a coolant check in the storage lot or driveway before the trip.
Air brakes
Diesel Class A coaches usually run air brakes fed by an engine-driven compressor. We find leaks, slow air build-up and moisture in the tanks, and service air dryers where fitted.
Diesel generators
Many pushers carry a diesel generator such as a Cummins Onan Quiet Diesel. We handle no-starts, fuel and engine-side faults on diesel gensets.
How A Visit Works
Diesel motorhome service where the RV is parked
Text us the coach, the chassis and engine, and what it is doing. Many campgrounds and storage lots have their own rules about repairs on the property, so check with the office before we come out.
At the coach we scan the engine and transmission and test the system that failed. Hoses, belts, filters and wiring are often fixed on the first visit. For larger parts we confirm the failure, get the correct part and install it on-site.
What to text us
- Year, make and model, plus chassis and engine
- Mileage or engine hours
- Where it is parked: campsite number, storage lot or address
- Warning lights, codes and dash photos
- What happened right before the problem
Diesel motorhome down in the Charleston area?
Call or text Lowcountry Diagnostics for on-site engine and chassis diagnostics.
Diesel RV and motorhome repair questions
Do you come to the campground, storage lot or driveway?
Yes. All of our work is done on-site. We service diesel motorhomes at campgrounds, RV storage lots and driveways across the Charleston area. Check the facility's rules on repairs first, and tell us about gate codes or access hours when you call.
Do you repair RV appliances, plumbing or slide-outs?
No. We work on the diesel engine and chassis side: engine, cooling, fuel, aftertreatment, transmission, air brakes, chassis batteries and wiring. For refrigerators, water and plumbing systems, slide-outs and other coach systems, an RV technician is the right call.
Which motorhome chassis and engines do you work on?
Diesel pushers on Freightliner Custom Chassis and Spartan chassis, older Blue Bird Wanderlodge coaches, and Super C motorhomes on Ford F-550 and Freightliner M2 chassis. Engines include the Cummins ISB, ISC, ISL and X12, plus the Caterpillar 3126E and C7 found in pushers built through about 2010.
My motorhome sat for months and now won't start. What should I check?
Chassis batteries are the first suspect after a long sit. We load test the batteries, check cables, grounds, the starter and the charging system, look at fuel supply and filters, and read engine codes before any parts get replaced.
My diesel pusher has a DPF warning. Can it be handled at the campsite?
Often, yes. Diesel motorhome engines built for 2007 and later use a diesel particulate filter, and 2010 and later engines add SCR with DEF. We read the codes, check sensors and the DEF system, run a parked regen when the system allows it, and handle DPF cleaning when the filter needs it.
Request Diesel RV & Motorhome Repair
Tell us where the motorhome is parked and what the engine or chassis is doing. For a coach that is stranded right now, calling or texting is fastest.
Stuck at the campground? Call or text (843) 310-0995.
Recent Repair Photos
A look at the repairs we make
Real field photos from Lowcountry Diagnostics, from engine diagnostics and electrical to hydraulic, HVAC, and heavy-duty truck service, handled on-site across the Charleston area.
Reviews
What Charleston truck owners and fleets say
“These gentlemen are very helpful and methodical about the way they go about diagnosing your truck I recommend them”
“He stayed on top of troubleshooting and never stopped until everything was fixed.”