GTA5518B 2321811 LP Turbo for Caterpillar C15 Acert | New

GTA5518B 2321811 Low Pressure Turbocharger for Caterpillar C15 Acert

GTA5518B

The GTA5518B (232-1811 / 10R-1888) is the Garrett low-pressure turbocharger in the compound twin-turbo system on the Caterpillar C15 Acert 15.0L engine. The C15 Acert, introduced in late 2003, was the first compound-turbo C15. The LP turbo is the larger unit without a wastegate — it mounts to the engine block with the exhaust system attached to its outlet. It pairs with the GTA4294BS high-pressure turbo, the smaller wastegated unit on the exhaust manifold. Fits BXS, MXS, and NXS engine serial prefixes. Garrett 741155-5003, CAT OEM 232-1811, 232-1805, 231-6616, 10R-1888, 291-3997, 245-7113. Built new, dynamically balanced, ships with gaskets. We supply shops, fleets, and distributors.

Turbo Model

GTA5518B (Garrett, low pressure, non-wastegated)

OEM / Interchange Numbers

0232-1805, 231-6616, 232-1811, 10R-1888, 291-3997, 245-7113

Application

1998-2013 Caterpillar C15 Acert 15.0L (low pressure; serial prefixes BXS, MXS, NXS)

Service & Support

1-Year Unlimited-Mileage Warranty
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FAQ

The GTA5518B (232-1811 / 10R-1888) fits the Caterpillar C15 Acert 15.0L compound twin-turbo engine, serial prefixes BXS, MXS, and NXS. CAT OEM numbers include 232-1805, 231-6616, 291-3997, and 245-7113; Garrett numbers run 741155-0001 through 741155-5003.

Low pressure. The GTA5518B is the larger turbo without a wastegate, mounted to the engine block with the exhaust system attached to it. The high-pressure turbo is the smaller wastegated GTA4294BS on the exhaust manifold.

Inspect both: check shaft play and oil leakage on each unit, and look for damage on the compressor wheels. Low boost with oil in the charge-air cooler usually points to the LP turbo; overboost or wastegate codes point to the HP unit. Given the labor to access the system, many shops replace both at the same time.

No. This unit fits BXS, MXS, and NXS prefixes. The SDP prefix uses a different LP turbo configuration. Check your engine serial number before ordering.

Brand new, 100% new components, dynamically balanced. Ships with gaskets. No core charge. One-year unlimited-mileage warranty.

Yes. US stock, volume pricing for shops, fleets, rebuilders, and distributors.

GTA5518B Low-Pressure Turbo for CAT C15 Acert: The Compound System

The C15 Acert uses two turbos in series. Exhaust hits the high-pressure GTA4294BS first for quick low-RPM spool, then flows into the larger low-pressure GTA5518B for top-end airflow volume. Knowing which turbo failed before ordering saves money — but with the labor involved in opening up the system, many shops replace both at once.

C15 Acert twin-turbo system

Position	Turbo	Identifiers
High Pressure	GTA4294BS	Smaller, with wastegate, mounted on exhaust manifold
Low Pressure (this page)	GTA5518B	Larger, no wastegate, mounted to engine block, exhaust attaches to it

The same compound layout is used on the C13 Acert with the GTA4088S (HP) and GTA4702B (LP) — smaller turbos for the 12.5L engine. Do not cross-reference C13 and C15 Acert turbos.

Serial prefix check

This GTA5518B fits BXS, MXS, and NXS serial prefixes (also covering 8LJ, B6J, KEH, KRA, RKS applications). It does not fit the SDP prefix, which uses a different LP turbo configuration. Check the engine serial number on the dataplate before ordering.

Common failure modes

Bearing wear — the LP turbo carries the full exhaust flow of the 15.0L engine. Shaft play, oil past seals, turbo whine at 400k-600k miles.
Compressor erosion — dust and debris over long service life reduce boost gradually.
Oil seal failure — restricted drain or high crankcase pressure pushes oil into the charge-air system. Blue smoke, oil in the intercooler.