4.0L Temperature Gauge Fluctuation / Thumping in Cooling System
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Post Fiend
Joined: Jan 2003
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From: Connecticut
4.0L Temperature Gauge Fluctuation / Thumping in Cooling System
I've seen a few posts recently regarding temperature gauge fluctuation and/or a "thumping" in the cooling system of the 4.0L OHV engine. I figured I would post a few TSBs that I have run across that are applicable to this issue:
ARTICLE NO. 97-18-9
• COOLING SYSTEM—TEMPERATURE GAUGE FLUCTUATION—VEHICLES WITH 4.0L ENGINE
• NOISE—“THUMPING” HEARD FROM WATER PUMP AREA—VEHICLES WITH 4.0L ENGINE
FORD: 1994-97 AEROSTAR, EXPLORER, RANGER
ISSUE
A “thumping” noise or temperature gauge fluctuation may occur on some vehicles. This may be caused by the water pump delivering an uneven flow throughout the engine.
ACTION
Replace water pump and gasket with revised Water Pump (F7PZ-8501-AA) and Gasket (FOTZ-8507-A).
Refer to the appropriate year Aerostar/Ranger/Explorer Service Manual, Section 03-03, for water pump replacement procedure.
PART NUMBER / PART NAME
FOTZ-8507-A / Water Pump Gasket
F7PZ-8501-AA / Water Pump
************************************************** ********
ARTICLE NO. 99-23-8
• 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—4.0LOHV ENGINE
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
1. Check for excessive exhaust system restrictions. A restricted exhaust could elevate cooling system temperatures.
2. If dash-mounted cooling temperature gauge fluctuates, check that gauge and sending unit are functioning properly.
3. Check for restrictions or kinks in the radiator or heater hoses.
4. Pressure check cooling system for leaks.
5. Confirm proper Engine Coolant Temperature (ECT) sensor signal to EEC-V processor.
6. Check for correct 50/50 coolant mix. Verify that freezing point is -37*C (±-15*C) or -35*F (±5*F).
7. 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.
PART NUMBER / PART NAME
F8PZ-8522-AA / Coolant By-Pass Kit (‘95-‘96 Ranger)
F8PZ-8522-CA / Coolant By-Pass Kit (‘97+ Ranger)
• COOLING SYSTEM—TEMPERATURE GAUGE FLUCTUATION—VEHICLES WITH 4.0L ENGINE
• NOISE—“THUMPING” HEARD FROM WATER PUMP AREA—VEHICLES WITH 4.0L ENGINE
FORD: 1994-97 AEROSTAR, EXPLORER, RANGER
ISSUE
A “thumping” noise or temperature gauge fluctuation may occur on some vehicles. This may be caused by the water pump delivering an uneven flow throughout the engine.
ACTION
Replace water pump and gasket with revised Water Pump (F7PZ-8501-AA) and Gasket (FOTZ-8507-A).
Refer to the appropriate year Aerostar/Ranger/Explorer Service Manual, Section 03-03, for water pump replacement procedure.
PART NUMBER / PART NAME
FOTZ-8507-A / Water Pump Gasket
F7PZ-8501-AA / Water Pump
************************************************** ********
ARTICLE NO. 99-23-8
• 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—4.0LOHV ENGINE
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
1. Check for excessive exhaust system restrictions. A restricted exhaust could elevate cooling system temperatures.
2. If dash-mounted cooling temperature gauge fluctuates, check that gauge and sending unit are functioning properly.
3. Check for restrictions or kinks in the radiator or heater hoses.
4. Pressure check cooling system for leaks.
5. Confirm proper Engine Coolant Temperature (ECT) sensor signal to EEC-V processor.
6. Check for correct 50/50 coolant mix. Verify that freezing point is -37*C (±-15*C) or -35*F (±5*F).
7. 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.
PART NUMBER / PART NAME
F8PZ-8522-AA / Coolant By-Pass Kit (‘95-‘96 Ranger)
F8PZ-8522-CA / Coolant By-Pass Kit (‘97+ Ranger)
Moderator
Joined: Jan 2004
Posts: 13,846
Likes: 110
From: SW Va
Had a similar problem with my 99 4.0L temp guage fluctuating, but no noise from the engine, as outlined in the TSB.
My fuel mileage had dropped off suddenly without a change in fuel vendors or driving habits.
The only thing I had noticed was a slightly lower than "normal" position in the coolant "idiot" temp guage. So I began to pay closer attention to it & caught it periodically, fluctuating up & down about 1/8 scale.
Replaced the OEM thermostat, about 37K miles on it, problems solved. Guage now stable, fuel mileage back to normal. Sticking thermostat I suppose.
Just some more input for consideration.
My fuel mileage had dropped off suddenly without a change in fuel vendors or driving habits.
The only thing I had noticed was a slightly lower than "normal" position in the coolant "idiot" temp guage. So I began to pay closer attention to it & caught it periodically, fluctuating up & down about 1/8 scale.
Replaced the OEM thermostat, about 37K miles on it, problems solved. Guage now stable, fuel mileage back to normal. Sticking thermostat I suppose.
Just some more input for consideration.
Freshman User
Joined: Aug 2004
Posts: 33
Likes: 0
From: El Dorado,Arkansas
I had a similar "thumping" in my '92 Ranger with the 3.0 and 5spd. Local Ford dealer could never find the problem, but speculated steam in a water hose was the problem. Glad to know that I was not imagining it.
Freshman User
Joined: Jul 2010
Posts: 32
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4.0
i am having this problem with a explore i replace the cap that stoped the leak stiill a thumping removed the therstat and all ok put in s new one bleed the air out i think and sitting still all ok took a road test the sounds came back upper water hose sucked shut and got to hot. i am stumped so now a water pump? its not leaking. a raditor?
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Posting Guru
Joined: Mar 2005
Posts: 1,533
Likes: 1
From: Dexter, MI
Hi, "fastcatboat." What year is your Ranger? Would the above information - especially Rockledge's post about the Coolant By-Pass Kit may be the solution to your problem.
In the future, I would suggest that you begin a new thread when you have an issue you want help on. Many folks will never find your question since it is buried at the tail end of a number of posts. Just a helpful note to someone fairly new to FTE.
In the future, I would suggest that you begin a new thread when you have an issue you want help on. Many folks will never find your question since it is buried at the tail end of a number of posts. Just a helpful note to someone fairly new to FTE.
New User
Joined: Oct 2012
Posts: 1
Likes: 0
95 ford ranger
hi folks, i have a problem with my ford ranger when i turn it off i have a bumping noise in my water lines it continues for some time after wards and my hoses collapse as a result what can you tell me if any body has happened come up on a solution for this thanks in advance.
Moderator
Joined: Jan 2004
Posts: 13,846
Likes: 110
From: SW Va
Welcome to FTE.
Have your radiator cap checked & the cooling system checked to see if its holding proper pressure.
What kind of condition is the coolant in????
Are you having an over heating problem when the engine is running????
Have your radiator cap checked & the cooling system checked to see if its holding proper pressure.
What kind of condition is the coolant in????
Are you having an over heating problem when the engine is running????
Posting Guru
Joined: Feb 2004
Posts: 1,388
Likes: 0
From: Saratoga, NY
hi folks, i have a problem with my ford ranger when i turn it off i have a bumping noise in my water lines it continues for some time after wards and my hoses collapse as a result what can you tell me if any body has happened come up on a solution for this thanks in advance.
New User
Joined: May 2010
Posts: 8
Likes: 0
Finally Fixed for good
OK, after dealing with this off and on for years I noticed that it doesn't happen when on max air conditioning or if the heater selector is off. Both these settings cause the vacuum-operated heater bypass valve to bypass the heater core. It seems that there is not enough flow through the heater core and this is causing a hot spot in the engine and creating steam pockets.
My solution was to create a permanent bypass on the heater core using reducer tees on the heater hoses with some 3/8" hose used for the bypass. After I installed it the symptoms went away and stayed away and I still get plenty of heat from my heater. I hope this helps if anyone comes back to this thread.
My solution was to create a permanent bypass on the heater core using reducer tees on the heater hoses with some 3/8" hose used for the bypass. After I installed it the symptoms went away and stayed away and I still get plenty of heat from my heater. I hope this helps if anyone comes back to this thread.
Thread Starter
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Post Fiend
Joined: Jan 2003
Posts: 9,748
Likes: 16
From: Connecticut
OK, after dealing with this off and on for years I noticed that it doesn't happen when on max air conditioning or if the heater selector is off. Both these settings cause the vacuum-operated heater bypass valve to bypass the heater core. It seems that there is not enough flow through the heater core and this is causing a hot spot in the engine and creating steam pockets.
My solution was to create a permanent bypass on the heater core using reducer tees on the heater hoses with some 3/8" hose used for the bypass. After I installed it the symptoms went away and stayed away and I still get plenty of heat from my heater. I hope this helps if anyone comes back to this thread.
My solution was to create a permanent bypass on the heater core using reducer tees on the heater hoses with some 3/8" hose used for the bypass. After I installed it the symptoms went away and stayed away and I still get plenty of heat from my heater. I hope this helps if anyone comes back to this thread.
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aerostar, car, coolant, el, explorer, f8pz8522aa, fluctuates, fluctuating, fluctuation, ford, gauge, system, temp, temperature, thumping
