Extra coolant hose?

[nathaniversen]

I have a 95 Limited and according to the gauge it's been running cold more or less since I got it by about 1/4 of the gauge and the heater is nowhere near hot; I changed the thermostat once before and it fixed the problem enough to where I could deal with it, but with it getting cold I decided to see if another thermostat would get it where it's supposed to be. This time though, I realized the truck has a hose I that haven't seen on any other Explorers, and the fact that it's held in place with a zip-tie makes me think it isn't a genuine Ford thing.

There's a brass T where one of the temp sensors would be with a sensor in one side and a hose coming out of the other, which runs to a T in the lower radiator hose.

Is this legit? Is it something special for the Limited's? It doesn't send the coolant around the thermostat and into the radiator, so what purpose could it be serving? Thinking path of least resistance, could this be allowing coolant to bypass the heater core?

 

[Thuggsy]

that's a bypass alright.

it's a 4.0 OHV?
mines a 97, i have a temp sensor in that location, no bypass hose.

personally id remove it and replace the lower hose. the only bypass thats needed is the heater core hoses.

 

[nathaniversen]

Yup, it is, OHV was the only option in 95. Mine has a temp sensor on the back side of the T, but the plug doesn't look stock, either.

I think I'll do that as soon as I can pick up a new hose. Thanks for replying.

 

[1993Saturn]

You have the By-Pass Kit 95-99 Explorer.

What you had is the Coolant Bypass Kit Ford# F8PE-8522-BA. Those are/were all factory parts.
It is also known as the "Heater Thump Service Fix," as stated on the Instruction Sheet [URL=http://www.explorerforum.com/forums/usertag.php?do=list&action=hash&hash=s]#s K-F8PE-8522-AA[/URL] .
There is a Service Bulletin from Ford 99-23-8 that corrects this issue. It is a very real problem.
Unfortunately, the kit has been discontinued and the Ford #s for the pieces are extinct, with no cross referencing information to aftermarket parts to duplicate it.
A couple of other threads are used for the rest of the posting below: http://www.explorerforum.com/forums/showthread.php?t=343246&highlight=heater+thump,
http://www.explorerforum.com/forums/showthread.php?t=64493&highlight=thump+in+hoses,

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)
_________________________
Burping the system correctly is also essential.
From the Service Manual:

Fill the cooling system with a 50/50 ethylene glycol and water mixture. Allow several minutes for trapped air to escape (bubble out) and for coolant mixture to flow through the radiator.

Install radiator cap to pressure relief position by installing radiator cap to fully installed position and then backing off to first stop. This will allow any air to escape, and minimize spillage.

Slide heater temperature and mode selection levers to maximum heat position.

Start engine and run at fast idle (approximately 2000 rpm) for three to four minutes. Shut engine off.

With engine off, wrap radiator cap with a thick cloth, carefully remove radiator cap and add coolant to bring coolant level up to filler neck seat.

Replace radiator cap to fully installed position. Then, back off to first stop. Operate engine at fast idle until the upper radiator hose (8260) is warm (water thermostat (8575) opens). To check radiator, shut engine off, wrap radiator cap with thick cloth and carefully remove radiator cap. Add coolant if necessary. Replace radiator cap to fully installed position.

Open the small cap on the top of the radiator coolant recovery reservoir. The large cap is for the windshield washer reservoir. NEVER put coolant mixture in windshield washer bottle.

Using a suitable suction gun, remove all coolant from radiator coolant recovery reservoir.

Add 1 liter (1.1 quarts) of 50/50 mixture of ethylene glycol and water to the radiator coolant recovery reservoir. Close the small cap.