Countries:

CANADA, MEXICO, UNITED
STATES

Document ID: IK1600272

Availability:

ISIS, FleetISIS, NotSIR

Revision:

0

Major System:
Current
Language:

CAB / SLEEPER / HOOD

Created:
Last
Modified:

12/2/2024

Author:

Steven
Bautz

English

Other Languages: NONE
Viewed:

12/19/2025

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Title : Cab and Windshield Water Leak Detection using Ultrasonic Sound Detector
Applies To : All International Truck Models

CHANGE LOG
Please refer to the change log text box below for recent changes to this article:

12/19/2025 - Initial Article Release

DESCRIPTION
This document will guide the user through a step-by-step procedure for detecting water leaks in vehicle cabs and windshields
using an ultrasonic sound detector.
Reference iKNow Article: IK1600131 - Cab Water Leak Troubleshooting Tips

SYMPTOM(s)
The customer indicates water leaking into the cab interior at a specific location.
Diagnostic Trouble Code(s) & Dashboard Indicator Light(s):
DTC/Light

Description

N/A - There are no DTC/Indicator Lights for this
condition
Customer Observations or Concerns: Customer indicates water leaking into the cab interior.

SPECIAL TOOL(s) / SOFTWARE
Tool Description

Tool Number

Comments

Instructions

Equalizer - Ultrasonic Leak Detector (or
similar)

ULF481

Purchase Locally/Online

Follow the manufacturer's
Instructions for use

Figure #1: Ultrasonic Sound - Leak Detector Examples

DIAGNOSTIC STEP(s)
Ultrasonic Leak Detection: Step-by-Step Procedure
1. Gather Your Equipment
Ultrasonic detector (transmitter, receiver + headphones).
Marker or masking tape (to mark the detected leak locations).
2. Prepare the Test Environment
Clean the vehicle from dirt, debris, snow, and ice. Be sure the truck is clean and dry.
Park the vehicle in a safe and quiet space to reduce background noise while performing the test.
3. Setup & Calibration
Following the manufacturer’s instructions for the ultrasonic transmitter, familiarize yourself with its tones and/or display
meter response by generating a reference tone (short burst of ultrasonic signal). There are YouTube videos that provide
real-life examples for ultrasonic leak detection for cab and windshield leaks.
Turn on the transmitter and place it inside the vehicle in a central location, such as the center dash console. Adjust the
sound sensitivity as needed according to the directions provided by the detector being used. Be sure all doors and
windows are completely closed during the scans to avoid false readings.
4. Perform Detection Scan
Slowly scan the cab features and interfaces that were noted as leak areas by the customer—especially seals, joints,
gaskets, and seams. (See IK1600117 for common cab leak areas like windshields, roof marker lights, Sunshade
mounting, Sleeper cap seams to metal cab roof, etc.) This article will help identify problem areas of the cab.
When the ultrasonic sound escapes through any gap, it emits a high-frequency noise that the detector picks up. These
locations can be marked during the test scanning for further investigation and repair after the entire test is completed.
(Note: there can be multiple leak locations involved.) A leak at the top of the windshield may actually be coming from the
roof marker light or exterior sunshade mount. The detector will help to pinpoint the leak quickly.
Mark any spot showing increased intensity of audible ultrasonic tone with a marker or tape.
Specific Examples:
Windshields: On the exterior of the cab, using the detector receiver pointing at the perimeter of the windshield at 1-2"
away, slowly move the detector and listen for leaks using the headphones. Start on the side/area where the customer has
indicated a leak was seen.
Roof Marker Lights: On the exterior of the cab, using the detector receiver pointing at the perimeter of each marker light
at approximately 1-2" away, follow the entire perimeter of the light fixture and also over each mounting screw.
Sleeper Roof Cap Seam: Place the transmitter inside the sleeper compartment, either on the sleeper cabinet countertop
or on the upper bunk, using a flat, clean surface like a piece of cardboard or notebook to place the transmitter on to avoid
blocking the speaker in the transmitter. From the exterior, approximately 1-2" from the sleeper cap seam, point the

detector towards the seam and move along the seam listening for a leak. If a leak is detected, mark the spot and continue
to test the entire seam, as the seal may have more than one gap that leaks.
Rubber Cab Door Seals: The detector can be used to find both water leaks and air (wind noise complaints) by scanning
the door's perimeter seal from the outside with the door closed.
5. Confirm & Document
Double-check the areas marked for leakage and repair as required.

Reference Links: Equalizer ULF481 - Ultrasonic Leak Detector

Figure #2: Examples of detector use

Standard Repair Time(s):
Refer to the SRT Manual for Repair Times

OTHER RESOURCES
Master Service Information Site

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