School Bus Coolant Tube Replacement by Make
Updated: Sep 10
Yes, Auto‑jet supplies replacement coolant tubes for Thomas Built and Freightliner school buses, matched by engine and OE number. Coolant tubes route engine coolant on rear-engine and conventional chassis, and the correct tube depends on the engine (Cummins ISC/ISB, Caterpillar C-7) and the OE number on the original tube. Match by the number stamped on the old tube.
What to Confirm Before Ordering a Coolant Tube
Coolant tubes are engine-specific and position-specific (upper, lower, forward, rear). Match the bus make, engine, and the OE number on the old tube. When the number is not legible, send the make, engine, and chassis and Auto‑jet will confirm the correct tube.
School Bus Coolant Tube Fitment by Make
Thomas Built (Cummins ISC / ISB, 1998 and up)
Cross-reference by OE number:
Auto‑jet Part # | Fits | OE Number |
CT769 | - | 6219-1769 |
CT549 | - | 6219-1549 |
CT145 | - | 6219-2145 |
CT761 | - | 6219-0761 |
CT208 | - | 6219-2208 |
CT551 | - | 6219-1551 |
CT375 | - | 6219-2375 |
CT078 | - | 6219-1078 |
CT379 | - | 6219-2379 |
CT231 | - | 6219-1231 |
CT755 | - | 6219-0755 |
CT396 | - | 6219-1396 |
CT146 | - | 6219-2146 |
CT633 | lower coolant tube, Cummins ISC | 138633 |
CT427 | lower coolant tube, Cummins ISC | 164427 |
CT834 | lower coolant tube, Cummins ISB | 151834, 151837 |
Freightliner
Auto‑jet Part # | Fits | OE Number |
CTFRL144 | Caterpillar C-7 engine | A05-22316-000 |
CTFRL405-0 | - | A05-22405-000 |
CTFRL766 | - | A05-22766-000, A05-22316-000 |
CTFRL316 | Mercedes engine | A05-22316-000 |
CTFRL692SS | C2 chassis, stainless | A05-30692-000 |
CTFRL316SS | C2 chassis, stainless | A05-22316-000 |
CT031SS | stainless | A05-30752-001, A05-29031-001 |
Blue Bird
Auto‑jet Part # | Fits | OE Number |
BBCT944SS | stainless coolant tube. Call to confirm the | for your chassis and engine |
How to Identify the Right Coolant Tube
Start with the bus make and engine (for example Cummins ISC, Caterpillar C-7).
Note the position: upper or lower, forward or rear engine.
Read the OE number on the old tube and cross-reference it.
Send the details to Auto‑jet to confirm the exact tube before ordering.
Call 800‑247‑5391 or request a quote with your bus and engine details.
Coolant tube failure often shows up alongside other cooling system wear. See School Bus Radiator Replacement: When Repair Is Not Enough to check the rest of the system.
Frequently Asked Questions
Which school buses do Auto‑jet coolant tubes fit?
Primarily Thomas Built (Cummins ISC and ISB engines) and Freightliner (Caterpillar C-7 and Mercedes), with additional stainless options. Auto‑jet cross-references by OE number.
Are coolant tubes engine-specific?
Yes. Coolant tubes are matched to the engine and their position on the chassis, so the engine and OE number must be confirmed.
Can Auto‑jet cross-reference my OE coolant tube number?
Yes. Send the OE number from the old tube along with the bus make and engine, and Auto‑jet will confirm the correct replacement.
