Yet another temp gauge thread.

[DrthTater]

My temp gauge reads high, then normal, then high, back and forth. Scares the heck out of me.

What I've done:

Water pump went bad, replaced water pump. Then the gauge started doing that, and I replaced the thermostat and the sending unit. It started spraying, located the spray coming from the rad cap. Replaced radiator cap, and developed a crack in the radiator. Replaced the radiator, and now the gauge still acts funky.

I am at a loss as to what to do next.


Any ideas?

 

[marragtop]

DOes the temp vary in all (highway and stop and go) conditions? Have you considered the fan clutch? Just a couple of thoughts...

 

[DrthTater]

DOes the temp vary in all (highway and stop and go) conditions? Have you considered the fan clutch? Just a couple of thoughts...

The gauge moves up and down no matter where I drive.


I hadn't considered the fan clutch. How do I tell if it's bad?

 

[Joe Dirt]

Mine will run at 1/3 normal. Under highway it'll run up to about 5/8, then drop down. It runs back and forth like that. It's been doing that ever since I put in my new Radiator, thermostat, all new coolant hoses, and such...

With the truck cold, spin the fan. If it spins more than a couple of times or won't turn at all (or very hard), the clutch is gone. If it freewheels, it won't keep up and cool. If it's tight, the clutch doesn't release on the highway and I think that's what my issue is.

 

[DrthTater]

Well, I have taken the truck to the place that rebuilt my transmission, and they scanned it will at idle, and while driving.

The temp gauge is fine, not faulty. And the temp while driving never got over 207 degrees.

I replaced the fan clutch.



Still rises to just under high.

Here's a picture of it (if you can see it, it's thumbnailed, click for a larger version)(It's from a camera phone, not the best quality)

 

[Joe Dirt]

Here is the wander on my gauge

 

[DrthTater]

If that were all the wandering mine did I wouldn't have made this thread. Mine goes from 1/3 to damn near H, then back down...

 

[DrthTater]

Took it to a shop to for a flush. They said it seemed like a seeping head gasket.

They took me into the shop, showed me the temp the engine was running at, the highest of which went to 210. He said that it looked like the head gasket was letting air into the coolant.

As of now, it's drivable.

Not sure if I'm going to keep the truck.

 

[DrthTater]

I have decided to keep the truck. Took it to a mechanic.


My truck is currently confuzzling the mechanic I took it to.

He is CONVINCED it's not a head gasket, and they replaced the thermostat, again, but they still have no idea what's causing it.

They think it MIGHT be air in the system, and they are going to try next.



He said it's frustrating him, because he's had it for nearly a week, and can't figure it out, lol

 

[my98nnj]

I'd be looking into the head gasket also. When they leak, exhaust gases can enter the cooling system, causing air pockets. That playes havoc on the coolant flow causing the temp to fluctuate. A simple test to see if exhaust gas is present in the cooling system should be performed. Any good mechanic should have the proper equipment to check that, if yours doesn't, call around to see who does. It may still be driveable, but if the leak gets larger the engine may eventually overheat on the road.

 

[ahodges]

Ok.. Here's what i found out when mine did that, Mine had a new engine, water pump, thermostat, sending unit, fan clutch, and radiator flush (been told its the cleanest they've seen with over 100,000 miles on it). Mine would peg the temp gauge then go back down to normal and would repeat.

I got frustrated with it and took it to a local dealer i really like and they had if for 4 days confused as i was. They pressure tested the water pump, replaced all the parts i already did, and scoped the radiator. At first they thought the head gasket was on wrong or leaking, performed a pressure test and no problem was found. They read posts from Ford about it and found 2 solutions, 1 being some type of a bypass kit.

Anyhow, they ended up putting a special water pump on it made by Ford for this problem because the conclusion was that the water pump was cavitating. Amazingly that fixed the problem. Now it hardly drifts in temp. at all and haven't had a problem for a year now.

If you were wondering about cost, they didn't charge me for even half the stuff they did to it because it took so long. That special water pump through Ford is listed at $200 bucks, which is ridiculous, but the dealer i got it from gave it to me for half price.

I hope this helps all of you...

 

[DrthTater]

Any they ended up putting a special water pump on it made by Ford for this problem because the conclusion was that the water pump was cavitating. Amazingly that fixed the problem. Now it hardly drifts in temp. at all and haven't had a problem for a year now.

If you were wondering about cost, they didn't charge me for even half the stuff they did to it because it took so long. That special water pump through Ford is listed at $200 bucks, which is ridiculous, but the dealer i got it from gave it to me for half price.

I hope this helps all of you...

Do you have a part number for that pump?

 

[ahodges]

Yeah, i could probably get it posted by sometime tonight. When i get home i'll look it up.

 

[ahodges]

Well i was unable to locate my reciept for it right now but here is the bulletin on the problem and the by-pass kit solution, which i didn't do..

Temperature Gauge Fluctuation On
1995-2000 Ford 4.0L OHV Engines

AERA members have reported a temperature gauge fluctuation on 1995-2000 Ford 4.0L OHV engines. Along with this fluctuation, the customer may complain of a knocking or thumping noise as well.

This noise is most pronounced with the engine at normal operating temperatures and heard in the passenger compartment of the vehicle. The noise is caused by steam formation in the cooling system. This noise is then transmitted through the heater hoses and heater core.

Ford offers a Coolant By-Pass kit to cure this problem. This kit increases the flow, which reduces steam formation in the cooling system. Refer to the chart listed below to get the correct By-Pass kit as it depends on the type of vehicle the customer has.

Application Coolant By Pass Kit

1997-2000 Ranger with auto or manual trans and F8PZ-8522-AA
1997-2000 Explorer with auto trans

1995-2000 Explorer with manual trans and F8PZ-8522-BA
1995-1996 Explorer with auto trans

1995-1996 Ranger with auto or manual trans F8PZ-8522-CA

The AERA Technical Committee

I'll keep looking for that water pump part number. If you go to a dealer they might be able to help you, or they'll just look at you dumb-founded, lol

 

[ahodges]

Well here are the service bulletins that are associated with the problem mine was having.


1) TSB Number: 99238 NHTSA Number: 6090164 TSB Date: November 15, 1999 Date Added to File: March 9, 2000
Failing Component:
Engine And Engine Cooling:Cooling System
Summary:
A temperature gauge fluctuation and / or a knocking / thumping noise may be audible inthe passenger compartment on some vehicles.
Discuss It in Forum

2) TSB Number: 97090297189 NHTSA Number: 54075 TSB Date: September 2, 1997 Date Added to File: March 30, 1998
Failing Component:
Engine And Engine Cooling:Cooling System
Summary:
Experiencing a "thumping" noise or tempeature gauge fluctation with some vehicles.


I couldn't find any other information on it but from one or both of these bulletins ford recommends that special water pump, with a part number, to fix the problem. The only way I know of to locate the part number for it is to take these service bulletin numbers to the dealer and ask about them..

 

[DrthTater]

I appreciate the help ahodges.

I have relayed the information to my mechanic. Hopefully this will help.

 

[ahodges]

Glad I could help out.. Let me know what solves your problem..

 

[DrthTater]

Glad I could help out.. Let me know what solves your problem..

Well, I talked to the mechanic today. He called ford and they said the bypass kit was the way to go. They also said that they had to get it from a "vintage warehouse," which my mechanic had never heard of, and it would take a week to get there.


If anyone can recommend a water pump that helps with cavitation, let me know :|

 

[gvsa123]

Mine does this occasionally (the rising temp), but it's more common to drop from normal op temp, to way near C, plus it's accompanied by a thumping noise as described on the TSB.

The question here is why suddenly? The truck is 12 years old. I got it last year, and these problems weren't there. The water pump shaft gave in, so I replaced that, and that's when it started to occur.

What exactly is cavitation?

 

[ahodges]

cavitation is when the pump pretty much "beats the water into submission" and causes air bubbles/ pockets to form as a result.. the water flow is not great enough for the amount of water the pump is capable of moving.. Don't ask me why it does it all of a sudden but my started right after putting a brand new water pump on.. then had to get it replaced right after with the special one.