We recently purchased a '95 F250, ext cab 4x2 long bed with a 7.3/auto. We started out getting around 12-14 mpg unloaded (have not pulled with it yet). This last monday, I put on a home made open element air filter, replaced the thermostat and performed a general service on the truck. We have not tested the mileage since then.

I noticed that the cooling fan makes an aweful lot of noise and it has a new fan clutch. Looks like the PO had replaced the fan clutch at some point. Is it normal to hear the fan wailing away even at higher RPM (like say 2200+)? This is my first PSD. My boss has an 03 with a 7.3 and it gets crappy fuel mileage as well, but it never gets used unless it's pulling 10,000 lbs+, and you never hear the fan. On the boss's truck you can turn the fan easily by hand even when cold. On mine, it is always very tight. Normal?

Also, I was looking into possibly doing a exhaust swap in the future. I don't want a ton of noise, but it's been my experience that the PSD isn't that loud even with no muffler (turbo eats up a lot of noise). What is a decent system that won't break the bank? I don't necessarily need 4" system when a 3 or 3.5 would be fine...the engine will stay stock other than intake and exhaust. Just need to open up the exhaust a little to allow a little better breathing. Suggestions?

 

exhaust- get rid of the catalatic convertor or gut it and that will help. use stock pipes is fine. get a downpipe ($150). it can be done cheap. selling the cat at scrap metal u can get $40.

 

Pulling the stock airbox and adding a NAPA 6637 air filter mod (search for "6637" and you should get plenty of info) is a good way to open up the intake side. A 3" or 3.5" downpipe and straight exhaust (no cat or muffler) should do you just fine.

Check your fuel pressure at the regulator. If it's like my '97 and fuel pressure is reading low, you can do an FPR Shim (search for that, too) to bring the pressure back into spec.

I've added the 6637 and done the FPR Shim and am using Diesel Kleen off and on when I fill up. My engine is smoother, quieter, and throttle response is great. Mileage went from ~16.25 MPG before to 17.5 MPG after these two mods alone. These are unloaded, combined city/highway MPG. Towing a 24' travel trailer and stuff, I get around 13 MPG.

Keep the questions coming. We love spending OPM.

 

What is the differential gear ratio?

Rog

 

The fan will decrease your MPG's, it's about 10-15 HP loss.
Does the fan ever quiet down or is it always on?
It should eventually quiet-down at higher RPM's unless it's running really really hot.
Maybe the PO installed the wrong fan clutch.

 

Rog,

3.73 is the rear gear. I'd have liked to have 4.10's but this is what it came with. The fan--it never quiets down which maked me believe that the PO probably bought a cheapie autozone fan clutch which won't "slip". I have run into this problem before on my 95 F150 and an older Mustang. Had to get the Motorcraft fan clutch and they aren't cheap. I wish I could put a good reliable E-fan on it but my father will be driving it and he doesn't watch gauges--so the stock OE fan is going to have to stay.

 

Not normal.
It will wail if coolant temps are high.
Check the running temp of the motor. It could be running to cold.

Bill

 

I agree with action. My fan would aslways turn off before I'd get to 2k.

 

There was a write up on here about adding an electric fan. Seems it was under $100 with a fan from the salvage yard. You may search and find it.

 

[QUOTE=mavman]
I noticed that the cooling fan makes an aweful lot of noise and it has a new fan clutch. On the boss's truck you can turn the fan easily by hand even when cold. On mine, it is always very tight. Normal?

I'd say that the fan clutch is not working properly. Mine spins easily by hand when cold.

 

i never hear my fan other than towing heavy in the summer

 

The fan should have some resistance to it. Have someone turn the truck off and see how long the fan spins. IIRC it should only be for 2-3 seconds.

I'm claiming mine is junk aswell. I've thought about the electric fan setup but they just can't handle the higher workloads and are somewhat un-efficient compared to the stocker.

 

Very true Farm.
But you do have a better chance with the hand shaker.

Bill

 

Looks like the fan clutch is for sure a big problem. Started the truck up today to move it around and it ran about 15 minutes total (got up to normal temp) and upon shutting it off, I watched the fan. It runs with the engine. When the engine kicks back just a little after it's turned off, the fan turns backwards with the engine...and after all this happens, it turns, but still tight. Doesn't matter whether hot or cold, it's always really tight compared to most any other fan clutch I've dealt with. Time for a new one.

I also did the 6637 filter mod--did that the other day. makes a big difference in response and power. I'm impressed. I thought about the BB mod, but I need to measure fuel pressure first. What gauge do I need? I have just a regular ol' cheapie autozone FP gauge that I measure the FP on my Merkur (same engine as a Mustang SVO and turbocoupe), will that work?

Thinking about a downpipe too...my brother did his '97 with a full 4" system and it really helped out the overall response of the engine. 'Course his is a straight system, no kitty and no muffler. I would like to retain some sort of muffler to keep noise down a little. That sound like a good idea, or just ditch the kitty and the muffler altogether?

And our scrap metal recycler gives a GOOD price for cats. Last one I cut off (from the Merkur...LOL) he gave me $54 for it. I thought it was a mistake until he told me that they have platinum inside.

 

I had an F150 that had a heavy duty fan clutch. That thing was loud and it stayed engaged longer. Maybe they put on something like that. Can you get a part number off it and see what it matches?