What This Cooler Is and Where It Lives
This is the engine oil-to-coolant heat exchanger that bolts to the block on the DD13/DD15/DD16 platform. It's a stacked-plate design - coolant runs through one side, oil through the other, and it pulls heat out of the oil before sending it back into the engine. Freightliner and Detroit Diesel both used this housing across a wide production run in the Cascadia.
When these fail you usually see it two ways: oil in the coolant (or vice versa) from a cracked plate, or high oil temp readings on the dash from internal clogging. Either way, you're pulling the old unit and matching the casting number stamped on it, not just guessing off the truck's build year.
How the Cross Numbers Line Up
A4721800965 shows up under a few different jackets depending on who's selling it. A4721800465 and the Detroit Diesel OEM number A4721802465 are the same core design with minor running changes Freightliner made over the production years - usually gasket surface or port fitting tweaks, not the core itself. 641273 is a common aftermarket/remanufacturer cross for the same housing.
The thing to watch on oil coolers isn't spline count like a driveline part - it's mounting bolt pattern, coolant port location, and oil passage sizing. A cooler that looks identical can have a different flow rate or port size and cause overheating or restricted oil flow that won't show up until you're already broken down.
Don't buy off the engine model alone. DD13s and DD15s ran multiple oil cooler revisions through their build years. Pull the number off the old cooler housing or run your VIN before you order - that's the only way to know which casting your truck actually needs.
Ordering From PartStop
We stock this cooler in Tacoma and it goes out same-day if you're local or need it trucked in fast. Nationwide shipping if you're not.
Every oil cooler we sell carries our 6+ month warranty. We're not going to tell you it's guaranteed to fit sight-unseen - cross-reference your old part's stamped number or VIN with our counter crew before you check out, and we'll confirm it matches before it ships.
A4721800965 Cross-Reference & Interchange Numbers
These manufacturer and aftermarket numbers commonly cross-reference to A4721800965. Use them to identify the part — then confirm the exact fit by VIN or the number stamped on your old unit before you order. An interchange is a starting point, not a fitment guarantee.
| Brand / Line | Cross-Reference Numbers |
|---|---|
| OE/Cross-Ref | A4721800465, 641273, AK-A4721800965 |
| Detroit Diesel (OEM) | A4721802465 |
Frequently asked questions
Does A4721800965 fit my DD15 Cascadia?
Likely, but DD15s ran through several oil cooler revisions over the years. Pull the number stamped on your old cooler or give us your VIN and we'll confirm before you order.
Is this the same as the Detroit Diesel A4721802465?
They're closely related - same core housing with minor production changes Freightliner made along the way. Match the number off your old cooler to be sure, since even small port or bolt-pattern differences matter on these.
What's the difference between A4721800965 and A4721800465?
They cross-reference to each other and are generally interchangeable, but they represent different production runs. Confirm against your old part number or VIN before installing - a wrong port size can cause coolant or oil flow issues.
Not sure it fits? We check before you pay.
Run your VIN and we’ll match parts to your exact truck, or call the counter — a person who knows trucks verifies fitment by OEM number before the order ships. No wrong-box returns.
More cross-reference guides
Need the part, not just the reading?
Every part below is a Premium Quality aftermarket Direct Replacement with published OEM cross-reference numbers, a 6+ month warranty and same-business-day shipping from Tacoma, WA. Not sure it fits? Run your VIN — or call and a person who knows trucks will verify fitment before you pay.