96 Explorer 2wd Thumping

[TexomaExplorer]

Hello everyone, I have a 1996 Ford Explorer 2wd v6 automatic and tonight I went out and started it there was a strange thumping sound.

I was in [P]ark, engine was idling, defrost was on and there would be a thump thump thump, very slow thump... Thump (1-2 second pause) Thump (1-2 second pause) Thump --- Then it would stop.

I could "feel" it thumping, almost as if someone was pounding on the underside of the explorer.

I got out and checked and made sure no animals were under the car, and that was all good. Got back in, idled it up again and let it settle, then the thump thump thump happened again..

Any thoughts?

 

[rb142]

Check all the belt drive pulleys, starting with the AC compressor.

Check the condition of the motor mounts.

 

[TexomaExplorer]

Checked everything. All seems fine. Noise hasn't happened again. Not sure what it was.

 

[masospaghetti]

Sounds like steam formation in your cooling system. I had the same thing on my 98.

Ford TSB 99-23-08 addresses this.

GAUGE - TEMPERATURE GAUGE FLUCTUATION AND/OR "KNOCKING/THUMPING" NOISE FROM COOLING SYSTEM - 4.0L OHV ENGINE
COOLING SYSTEM - PULSATING COOLANT FLOW - NOISE - "KNOCKING/THUMPING" - AUDIBLE IN PASSENGER COMPARTMENT - 4.0L OHV ENGINE
NOISE - "KNOCKING/THUMPING" - COOLING SYSTEM - AUDIBLE IN PASSENGER COMPARTMENT - 4.0L OHV ENGINE
Publication Date: NOVEMBER 4, 1999

FORD:
1995-2000 EXPLORER, RANGER
This TSB article is being republished in its entirety to include 2000 model year vehicles and to provide Service Part(s) and Labor Time information.

ISSUE:

A temperature gauge fluctuation and/or a "knocking/thumping" noise may be audible in the passenger compartment on some vehicles. This noise is most pronounced with the engine at normal operating temperature. The noise is caused by steam formation in the cooling system. The noise is then transmitted through the heater hoses and heater core.

ACTION:

Install a Coolant By-Pass Kit. This increases coolant flow which reduces steam formation. Refer to the following Diagnostic and Service Procedure for details.

DIAGNOSTIC AND SERVICE PROCEDURE

Check for excessive exhaust system restrictions. A restricted exhaust could elevate cooling system temperatures.
If dash-mounted cooling temperature gauge fluctuates, check that gauge and sending unit are functioning properly.
Check for restrictions or kinks in the radiator or heater hoses.
Pressure check cooling system for leaks.
Confirm proper Engine Coolant Temperature (ECT) sensor signal to EEC-V processor.
Check for correct 50/50 coolant mix. Verify that freezing point is -37°C (±-15°C) or -35°F (±5°F).
If concern still exists, install service Coolant By-Pass Kit and verify that concern has been resolved. Refer to the Application Chart in this article.



COOLANT BY-PASS KIT CONTENTS
Application Coolant By-Pass Kit (-8522-) T-Fitting By-Pass Tube Hose Assembly Instruction Sheet
1997-2000 Ranger with automatic or manual transmission and 1997-2000 Explorer with automatic transmission F8PZ-AA Yes Yes Yes Yes

1995-2000 Explorer with manual transmission and 1995-1996 Explorer with automatic transmission F8PZ-BA Yes Yes Yes Yes

1995-1996 Ranger with automatic or manual transmission F8PZ-CA Yes Yes Yes Yes



PART NUMBER PART NAME
F8PZ-8522-AA Coolant By-Pass Kit
F8PZ-8522-BA Coolant By-Pass Kit
F8PZ-8522-CA Coolant By-Pass Kit
OTHER APPLICABLE ARTICLES:

97-18-9

SUPERSEDES:

99-7-2