---
slug: diesel-air-intake-and-exhaust-maintenance
title: "Diesel Air Intake and Exhaust Maintenance: What a PM Covers"
description: "Why air intake and exhaust get their own place in a diesel PM on trucks, generators, and marine engines, how a marine exhaust elbow differs, and what the customer's record should show."
track: maintenance
kind: article
isRegulatoryAdjacent: false
publishedAt: 2026-10-18
source: https://shopbluecollarparts.com/kb/diesel-air-intake-and-exhaust-maintenance
license: CC BY 4.0
---

# Diesel Air Intake and Exhaust Maintenance: What a PM Covers

**A diesel engine breathes a great deal of air, and everything it breathes in has to be clean and everything it breathes out has to leave safely.** The intake side protects the engine from dirt. The exhaust side carries heat and gases away from the engine, the equipment, and the people around it.

This page describes intake and exhaust at the category level. The parts to check, service intervals, and procedures come from the manufacturer's documentation.

## Air intake and filtration

Dust that gets past the air filter wears an engine from the inside. The intake section of a PM looks at the filtration and the path air takes to the engine, because a filter is only as good as the seal and the ducting around it. Equipment that works in dusty conditions, such as construction sites, farms, and gravel yards, asks more of this system.

## Exhaust

- **Trucks and generators** route exhaust away from the engine and the operator. On a generator, especially one installed in or near a building, where the exhaust goes matters as much as how the engine runs.
- **Marine diesels** usually mix cooling water into the exhaust at an elbow or riser. Where hot exhaust meets salt or fresh water, metal wears and corrodes, so marine PM gives the exhaust and its cooling connection their own attention. See [marine corrosion and anodes](/kb/marine-engine-corrosion-and-anodes) for the related wear.

Emissions and aftertreatment systems on newer engines have their own manufacturer requirements; follow that documentation.

## What the customer's record should show

The record should say what was inspected on the intake and exhaust side, what was serviced or replaced, what condition it was in, and anything to watch. See [what belongs in a PM report for the customer](/kb/what-belongs-in-a-pm-report-for-the-customer).

For the full visit on each type of equipment, see the [semi truck](/kb/semi-truck-preventive-maintenance-checklist), [diesel generator](/kb/diesel-generator-maintenance-checklist), and [marine diesel](/kb/marine-diesel-engine-maintenance-checklist) PM pages.

## Record it in Blue Collar Parts

Where this system sits depends on the equipment. The truck PM form has an **Air Intake & Air Filtration** section, where an air filter restriction reading can go with the filter item. The marine form has an **Exhaust System & Elbow** section. The generator form covers both in one **Air Intake & Exhaust System** section. Findings, readings and notes are entered item by item, and they land in the record your customer receives. See [how to record a PM service](/kb/record-a-pm-service), then [send the record to your customer](/kb/send-a-record-to-your-customer).

---

*Preventive maintenance is not a federal annual inspection and does not establish regulatory compliance. This page describes a system at the category level. Use the equipment manufacturer’s current service documentation for the items to check, procedures, specifications, and service intervals.*

## Sources

What BCP does here: Blue Collar Parts records the work and sends the report to your customer. It does not perform, certify or approve inspections.
Reviewed 2026-10-18