# Service bulletin B170100

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: 10244236
- Published by NHTSA: 2023\-11\-01
- Manufacturer's number: B170100
- Manufacturer's date: 2023\-10\-16
- NHTSA component: ENGINE AND ENGINE COOLING

## NHTSA's summary

The lower radiator coolant return hose may come in contact with the secondary air system check valve flange gasket when the engine coolant is at operating temperature due to coolant system pressure and expansion of the hose.

## The document

- [NHTSA's copy of the document (PDF)](https://static.nhtsa.gov/odi/tsbs/2023/MC-10244236-0001.pdf)
- [If that address does not open, try this one](https://static.nhtsa.gov/odi/tsbs/2023/MC-10244236-9999.pdf)

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

## Components

Engine

## Vehicles listed

- 1999 BMW 540I
- 1999 BMW 740I

## Other bulletins for the same vehicles and component

- [B122817](/bulletins/10142928.md), 2018-07-16, Service bulletin: ENGINE AND ENGINE COOLING; ELECTRICAL SYSTEM:SOFTWARE. SERVICE ACTION: PROGRAM DME \(FOR O2 SENSORS\): Due to DME software error, the following oxygen sensors plausibility fault codes may be stored in DME 5.2.1 control module:

JSON: [/v1/bulletins/10244236](/v1/bulletins/10244236)

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