What This Cooler Is and Where It Lives
This is the stacked-plate oil cooler that bolts to the block on DD13 and DD15 engines in the Cascadia. Coolant runs through the plate pack, engine oil runs around it, and heat transfers off before the oil goes back through the system. 13 plates is the count on this specific version — DD engines have had different plate counts over the years depending on application, so plate count matters here, not just the engine family.
When these go bad you'll usually see oil in the coolant, coolant in the oil, or the cooler just can't keep up and oil temps climb under load. Sometimes it's a cracked plate, sometimes it's just packed solid with scale after 400-500k miles and coolant's not flowing through it anymore.
This is a housing-mounted cooler — it's not the whole assembly with the housing itself, so check whether your old part is the cooler element or the cooler-and-housing combo before you order.
How the Cross Numbers Line Up
A4711800865 is the Freightliner/Detroit number stamped on this cooler. It crosses to A4721802365 as a Detroit Diesel OEM number and to 641272 in some parts catalogs — same physical part, different number depending on who's cataloging it. The AK-A4711800865 you'll see is just an aftermarket house number tied to the same application.
Where guys get burned on oil coolers is plate count and port location. DD13/DD15 coolers have run in different plate configurations over the model years, and the mounting bolt pattern plus coolant port orientation has to match your block exactly — there's no universal fit here even within the same engine family.
Surest way to confirm: pull the number off your old cooler or run your engine's serial/VIN. Don't go by 'it's a DD15 so any DD15 cooler works' — Detroit changed spec more than once on this.
Ordering From PartStop
We're in Tacoma and keep these in stock for same-day pickup or will/call — if you're a fleet running Cascadias through the Northwest corridor this is a common failure part and we see it come through regular.
Ship nationwide too, most places next day or two-day depending on where you're at. We back it with a 6+ month warranty, which is longer than you'll get slapping a used one in.
Give us the old part number or your VIN before you order if there's any doubt. Takes two minutes on the phone and saves you a return shipment if the plate count or port config doesn't match.
A4711800865 Cross-Reference & Interchange Numbers
These manufacturer and aftermarket numbers commonly cross-reference to A4711800865. 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 | 641272, AK-A4711800865 |
| Detroit Diesel (OEM) | A4721802365 |
Frequently asked questions
Does A4711800865 fit my 2015 Cascadia with a DD15?
Likely, but confirm the plate count matches — Detroit ran different oil cooler configs across model years even within the DD15 line. Pull the number off your old cooler or give us your engine serial and we'll verify before you order.
Is this the same as the Detroit OEM A4721802365?
Yes, that's the Detroit Diesel OEM cross for this same cooler — different number, same physical part and application. This one's the aftermarket version at a lower price point, same fit.
My cooler's leaking coolant into the oil pan — is that always this part?
That's the classic symptom of a cracked oil cooler plate, so it's the first thing to check, but flush the system after replacement regardless. Contaminated coolant sitting in there will kill the new cooler too if you don't get it clean.
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.