Drew Callahan · June 27, 2026
The air dryer cartridge in your Tiffin Allegro bus is one of those components that doesn’t get much attention until your air brakes start acting up. I’ve replaced plenty of these over the years, and I can tell you the difference between doing it right and doing it wrong is night and day. Here’s what … Read more
Drew Callahan · June 2, 2026
Key Takeaways The Tiffin Allegro Bus uses the HWH hydraulic leveling system — one of the most reliable in the industry, but still vulnerable to low fluid, blown fuses, and failed solenoid valves.Low hydraulic fluid is the single most common…
Drew Callahan · June 1, 2026
Key Takeaways The Cummins ISL 8.9L engine in the Tiffin Allegro Bus has six primary coolant leak points: the water pump weep hole, coolant filter housing, EGR cooler, charge air cooler, hose connections, and freeze plugs.A cooling system pressure test…
Drew Callahan · March 15, 2026
Skip this repair and your Tiffin Allegro Bus AC won’t just underperform—it’ll trap you in a rig that either won’t cool at all or keeps nuking your breaker every time you fire it up. A weakening capacitor or dragging fan motor is the kind of failure that sneaks up: one week the AC is sluggish … Read more
Drew Callahan · March 14, 2026
“Drew, my Allegro Bus furnace clicks three or four times before it finally catches, and half the time it just blows cold air. Is this an igniter thing, or am I looking at something bigger?” I get that question more than I’d expect, and the answer’s usually yes to both. The Tiffin Allegro Bus furnace … Read more
Drew Callahan · January 7, 2026
Diesel Engine Cooling System Service for TIFFIN ALLEGRO BUS Tiffin Allegro Bus owners living in the Southwest or running extended boondocking seasons hit a wall around 70,000–90,000 miles when the cooling system decides to leak. Not dramatically — just a slow, persistent weep from the lower radiator tank or a water pump that’s crying a … Read more
