# Service bulletin 21NA237

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.

- Type: Service bulletin
- NHTSA id: 10207914
- Published by NHTSA: 2022\-02\-14
- Manufacturer's number: 21NA237
- Manufacturer's date: 2021\-12\-16
- NHTSA component: UNKNOWN OR OTHER; ENGINE AND ENGINE COOLING:COOLING SYSTEM

## NHTSA's summary

THis technical bulletin provides a procedure to perform a cooling system flush to remove possible debris from the cooling system pipes.

## The document

- [NHTSA's copy of the document (PDF)](https://static.nhtsa.gov/odi/tsbs/2021/MC-10207914-0001.pdf)
- [If that address does not open, try this one](https://static.nhtsa.gov/odi/tsbs/2021/MC-10207914-9999.pdf)

The document is the manufacturer's. This site does not hold it.

## Components

Engine, Cooling system

## Vehicles listed

- 2021 CADILLAC ESCALADE ESV
- 2021 CADILLAC ESCALADE NA
- 2019 to 2021 CHEVROLET SILVERADO 1500
- 2020 to 2021 CHEVROLET SILVERADO 2500
- 2021 CHEVROLET SUBURBAN
- 2021 CHEVROLET TAHOE
- 2019 to 2021 GMC SIERRA 1500
- 2020 to 2021 GMC SIERRA 2500
- 2021 GMC YUKON
- 2021 GMC YUKON XL

## Other bulletins for the same vehicles and component

- [22NA013](/bulletins/10212629.md), 2022-05-31, Service bulletin: ENGINE AND ENGINE COOLING:COOLING SYSTEM. This technical bulletin provides a procedure for the technician to check and tighten the CAC plumbing if found loose.
- [20NA166](/bulletins/10212560.md), 2022-05-31, Service bulletin: ENGINE AND ENGINE COOLING; ENGINE AND ENGINE COOLING:COOLING SYSTEM:HOSES/LINES/PIPING/FITTINGS. This informational bulletin advises the technician of possible coolant entering the areas of the engine, either through failed parts or defects in the castings, that may be the cause of the concerns related to the MIL or the engine running rough.
- [21NA257](/bulletins/10205577.md), 2021-12-27, Service bulletin: ENGINE AND ENGINE COOLING:COOLING SYSTEM; EQUIPMENT ADAPTIVE/MOBILITY; EQUIPMENT. This service bulletin provides a service procedure to correct a customer concern of a Malfunction Indicator Lamp \(MIL\) Illuminated \- DTC P3075 Set.
- [21NA237](/bulletins/10205563.md), 2021-12-27, Service bulletin: EQUIPMENT; ENGINE AND ENGINE COOLING:COOLING SYSTEM:HOSES/LINES/PIPING/FITTINGS. THis technical bulletin provides a procedure to perform a cooling system flush to remove possible debris from the cooling system pipes.
- [18NA103](/bulletins/10183153.md), 2020-11-30, Service bulletin: FUEL SYSTEM, GASOLINE; ENGINE AND ENGINE COOLING:COOLING SYSTEM:PUMP. This service bulletin provides information to correct a customer concern of an in\-tank fuel pump whining noise, engine hard to start and/or stalls and Malfunction Indicator Lamp \(MIL\) is illuminated.
- [PIT5789](/bulletins/10182582.md), 2020-11-16, Service bulletin: ENGINE AND ENGINE COOLING:COOLING SYSTEM:PUMP; ELECTRICAL SYSTEM:SOFTWARE. This Preliminary information communicates an issues with an SES MIL and DTC P2B87 setting. Engineering is working on releasing updated BCM cals to correct the concern.
- [PIP5684B](/bulletins/10178370.md), 2020-08-10, Service bulletin: ENGINE; ENGINE AND ENGINE COOLING:COOLING SYSTEM; EQUIPMENT. This Preliminary information communicates the use of air leak diagnostic test tool CH\-52250 in addition to the information found in the service manual.
- [20NA010](/bulletins/10176620.md), 2020-06-22, Service bulletin: ENGINE AND ENGINE COOLING:COOLING SYSTEM:FAN. This technical bulletin provides a procedure to replace the cooling fan if found contacting the shroud causing the customers concern.
- [N192266750\-02](/bulletins/10172664.md), 2020-03-23, Service bulletin: FUEL SYSTEM, DIESEL; EQUIPMENT; ENGINE AND ENGINE COOLING:COOLING SYSTEM:FAN; ELECTRICAL SYSTEM. Service Update \- On vehicles that are equipped with a 6.6L diesel engine, may have one or more of the following conditions exist: 1. The instrument panel cluster may incorrectly display the message ?DEF Low? when a diesel exhaust fluid \(DEF\) controller internal fault is detected \(DTC P20FF\), instead of displaying the proper ?Service DEF System? message. 2. The customer may complain of excessive engine fan noise at a low vehicle speed. 3. Under certain conditions, the diagnostic system may set one of the following DTC?s when there is no problem with a component: \(P20EE, P226D, P16F3 and P129F\). Dealers are to reprogram the engine control module and perform NOx and Catalyst Resets and Regen Enable.
- [19NA104](/bulletins/10163237.md), 2019-07-29, Service bulletin: ENGINE AND ENGINE COOLING:COOLING SYSTEM:RADIATOR ASSEMBLY. This informational bulletin provides information for dealers/technicians and customers on steam/vapor coming from the front grille or radiator area.

JSON: [/v1/bulletins/10207914](/v1/bulletins/10207914)

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