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Service bulletin 18NA378

A bulletin is a manufacturer's communication to its dealers, as NHTSA indexes it. The summary is NHTSA's. The document is the manufacturer's: read it at NHTSA. A bulletin is not a recall, and listing a model year does not mean every vehicle of it is concerned.

The communication, as NHTSA indexes it (as of 2026-10-19)
TypeService bulletin
NHTSA id10155004
Published by NHTSA2019-03-25
Manufacturer's number18NA378
Manufacturer's date2018-12-17
NHTSA componentENGINE AND ENGINE COOLING; POWER TRAIN

NHTSA's summary

This technical bulletin provides a procedure to replace the fluid cooler exchanger and the torque converter or transmission and torque converter, depending on if the exchanger leaked into the transmission fluid.

The document

The document is the manufacturer's. This site does not hold it. NHTSA files a document at one of these two addresses; we have not asked NHTSA which.

Components

Engine, Transmission and driveline

Vehicles listed
CADILLAC XT42019

Listing a model year does not mean every vehicle of it is concerned: the document says which.

Recalls for the same vehicles and component
20V6680002020-10-29. POWER TRAIN:AUTOMATIC TRANSMISSION

A recall listed here may apply to some of the same vehicles. Only the manufacturer can say whether it applies to one vehicle.

Other bulletins for the same vehicles and component
00-06-01-026R2025-12-03. Service bulletin. This service bulletin provides information on replacing the intake manifold when the engine is replaced after severe internal engine damage.
23-NA-1532025-10-25. Service bulletin. The service bulletin advises the tech of a normal transmission shift condition and the delay in throttle response when the throttle plate is opened rapidly and advises the customer that it is normal for the delay.
15-NA-0102025-07-07. Service bulletin. This service bulletin provides information to dealership personnel for new vehicles with less than 1,000 miles that may not pass California smog inspection or smog inspection in other states.
21-NA-2402025-06-16. Service bulletin. This service bulletin provides diagnostic repair information to correct an oil leak in the engine.
PI0281L2025-06-12. Service bulletin. This preliminary informational (PI) bulletin provides information to dealership personnel that may be helpful when addressing underbody component corrosion with customers.
25-NA-1002025-06-12. Service bulletin. This warranty administration bulletin provides policy information on vehicles outside of a California Emissions State who move to and register their vehicle in a California Emission State may be entitled to the 7 year, 70,000-mile Emission Select State Component Limited Warranty.
21-NA-1392025-05-01. Service bulletin. This service bulletin provides a repair procedure to correct a customer concern of a Malfunction Indicator Lamp (MIL) Illuminated - DTC P3055 Set.
25-NA-0522025-04-28. Service bulletin. This bulletin advises the technician to flush the cooling system multiple times if oil has been found in the cooling system and replace the parts that may be contaminated due to oil in system.
25-NA-0522025-04-10. Service bulletin. This bulletin advises the technician to flush the cooling system multiple times if oil has been found in the cooling system and replace the parts that may be contaminated due to oil in system.
22-NA-0942025-03-12. Service bulletin. This service bulletin provides repair information to correct a customer concern of a loss of cabin heat.