Fluctuating Eng Temp Gage 97 Ford 460

[bobfo]

Typical problem-Outside temp 70,level to rolling road,gauge resting on "O" normal. Gauge will rise to "M" fan clutch will kick on and withen 30 seconds gauge will return to "O". Problem this cycle repeats about every 10 minutes or less for an entire trip. Ford dealer flushed radiator,install new 195 thermosdat no change. Warmer outside temp cycle repeats more often. Unit has new belts,fluids,etc. Any ideas?

Thanks
bobfo 97 Nat Dolphin

[Lt46]

Hmmm, you just described exactly how my 97 F53 w/460 runs! I thought it was just the way it works. For me, the steady on/off (very annoying) of the fan clutch is what bothers me most. I've done the T-stat change, cleaned the radiator fins and replaced all belts. Will be replacing/flushing coolant this spring. I'm wondering if the OEM fan clutch is overly sensitive because my dash temp. guage never indicates that the engine is too hot.

[mpaton]

You have insufficient airflow through the radiator. When the motorhome manufacturer got the chassis from Ford, they were supposed to build some way to let air in through the front, and get it to go through the radiator. Most didn't do the second part, they just let air fall on the front of the radiator and then fall out the bottom of the chassis, or out the sides. Sometimes they will fit a flexible baffle to stop the air missing the radiator by going over the top of the radiator, but repair shops and owners are good at not putting that back.

It's just poor airflow management; at least the engine has a fan which can clutch in to cool it off. This poor airflow also badly affects your transmission cooler, and Ford didn't fit it with a fan. This isn't good for transmission life.

[Topflite51]

Got tired of listening to my clutch fan so I installed a thermostatically controlled electric fan, don't hear it and rarely does the clutch fan come on.

Air flow is definitely the problem.

[jupoa]

The front of your radiator may be partially plugged with lint or dirt.

When you look through your open engine access panel towards your radiator, the fins you see are not part of your radiator, they are your AC condenser coil which pretty much covers the whole front of your radiator. To see the front of your radiator, look up from underneath the assembly. You will see the condenser coil in front and the face of the radiator about an inch and a half behind it. That's how it is on my '97 460 anyhow.

My radiator was covered with a kind of lint looking material even though the face of the condenser coil was pretty clean. Could not dislodge most of the lint by trying to blast through the condenser coil with water or air. Had to make a short, wide short bristled brush on a long handle to reach up from underneath and brush the lint from the face of the radiator. Wear eye protection as you must have your face directly underneath the radiator to see what your doing. Have no idea what the "lint" actually was or why it was there but removing it made a significant difference.

My clutch does not engage the fan unless its a hot day and I'm climbing a long grade or bucking a substantial head wind. It does not oscillate on and off periodically. Of course, I also have a full Banks setup which is really effective at sucking exhaust heat away from the engine.

Good luck.

[justimagination]

.........The system is working as it was designed, maybe too often. Check you overflow bottle when COLD, make sure water line is on the correct amount as marked COLD. After your next trip, wait till engine is dead cold and check the level again, it it's not where you checked it last, there is a leak somewhere. I found on our m/home the small hose from the radiator going into the overflow tank was leaking, only solution was to put a small mini-clamp on the top portion of the tank where the hose went through, problem solved. The system has to be sealed, low coolant will cause excessive changes in TEMP gauge, causing the clutch fan to engage. Let us know what you find, will try and help you resolve. Good luck,
David G.

[bobfo]

Thanks everyone for the tips and info.
Going to follow everyone and see what happens,
Will post results when complete.

Again, thanks

bobfo

[bobfo]

[QUOTE=bobfo;813144]Typical problem-Outside temp 70,level to rolling road,gauge resting on "O" normal. Gauge will rise to "M" fan clutch will kick on and withen 30 seconds gauge will return to "O". Problem this cycle repeats about every 10 minutes or less for an entire trip. Ford dealer flushed radiator,install new 195 thermosdat no change. Warmer outside temp cycle repeats more often. Unit has new belts,fluids,etc. Any ideas?

Thanks
bobfo 97 Nat Dolphin[/QUOTE

Update on Temp problem. Followed all suggestions. Found large gap about 12" from front grill and radiator allowing wind to deflect under radiator. Installed temporary 1/4" X 12"X5' plywood to block air from passing under radiator.. Overflow tank checked OK no leakage. During 300 mile round trip to Goshen rally, I found the items above did Not improve the problem. I don't think the system is overheating. Could this be a slow acting thermo? Would installing a cooler thermo help without hurting performance?

Thanks

bobfo

[Eric_H_E]

Really depends on just how hotnit is getting. If I remember correctly the hotter it run, the more efficient. But harder on everything.

[jupoa]

I have also heard that a hotter engine runs more efficiently, up to a point of course.

My temp guage was always fluctuating in the lower range except under extreme circumstances. I cleaned the radiator, checked hoses, etc. What seems to have made the biggest difference was changing the thermostat. Replaced the stock unit with a 195 degree from Autozone and my guage always stays in the middle now after warmup.

My fan clutch still seldom engages and certainly not in a periodic manner.

Are you sure the dealer actually replaced your thermostat?

[TNMike]

Quote:

Originally Posted by jupoa The front of your radiator may be partially plugged with lint or dirt. My radiator was covered with a kind of lint looking material even though the face of the condenser coil was pretty clean. Could not dislodge most of the lint by trying to blast through the condenser coil with water or air. Had to make a short, wide short bristled brush on a long handle to reach up from underneath and brush the lint from the face of the radiator. Wear eye protection as you must have your face directly underneath the radiator to see what your doing. Have no idea what the "lint" actually was or why it was there but removing it made a significant difference.

My '97 was covered like this too! I chalked it up to mice building a nest with old blankets in the barn I bought the motorhome out of, but who knows. Using sheet metal I built a box from the front grill around the front of the radiator/condenser, it helped noticeably on the next trip. Lots of air was escaping over the battery and around the passenger tire area.