Fans and Warmer Weather

[threejacks]

Early last fall I had to replace my water pump. I replaced all the coolant while doing so. Decided to replace thermostat while I was at it. I had been looking at threads on the 203 degree thermostats and went to NAPA and asked for a stock thermostat. To my surprise it said 205 degrees . I put everything back together but left my fan off. In the past my truck temp gauge stayed near the R M on my idiot light factory gauge. All this winter it stayed bearly on the N and sometimes on the O but always somewhere in the NORMAL range. Always cooler than I like or was use to seeing. Now that warmer weather is coming I am looking at installing a dual electric fan and have seen write ups for installs but haven't been able to find now that I am ready to install. I would like to have one wired to come on auto when needed and the other to come on with a switch. Truck runs a lot quieter and seems to have quicker acceleration from idle without fan and all that weight. Thanks for any input.

 

[Dieselpwrdredneck]

Here is a thread from a while back there is some good discusion about electric fans:

http://www.superdutydiesel.com/forums/showthread.php?t=2501

Hope it helps

Neal

 

[threejacks]

That's the thread I couldn't find for some reason. Any comments about the NAPA 205 degree thermostat. Any DIY on wiring and hooking those relays up? Where is the probe installed on the relay JOAT is using? I have a dual electric fan off a 95 Ford Windstar. Looks like top bolt holes will match with out any changes.

 

[Crumm]

Any comments about the NAPA 205 degree thermostat.

Until 1996, all 7.3L Powerstrokes that were manufactured used an International water pump and an International short stem 203* thermostat . In 1996, Ford changed to a lower degree 195* thermstostat. They changed water pump designs at this time as well. The new pumps required the new long stem 195* thermostat in place of the short stem to properly seat the bypass disk. All 1996-2003 Ford PSDs now come equipped with a long stem 195* thermostat. Since your truck is a 1995 it has the short stem thermostat which is available in 203* or the 205* like you purchased at NAPA. The threads on the special 203* thermostat from Dieselsite are directed at 1996 and newer trucks. Your stock thermostat was already a 203 or 205.

Long story short: For a 1995 you got the right one at NAPA..

 

[threejacks]

Any suggestions on how to hook these fans up?

 

[JOAT]

Not sure about the wiring on the dual fans. Should be able to separate them and run individually, but I haven't seen one up close.

I put the probe towards the top of the radiator and behind where the transmission cooler is (automatic).

I personally recommend using a 40amp relay to power each fan. Use any hot in run power source thru the manual and thermostat switches to activate the relay(s). Fan power into the relays should come directly from the battery, with a fuse at the battery of course.

Don't have a schematic for the dual fan but here's a schematic for wiring a single speed fan:

 

[threejacks]

Thanks Joat. This is what I am looking for. I was wanting one fan hooked up the way your diagram is, and then the second fan totally independent from the first one. I am planning to wire it up with only a manual switch to use in extreme cases. I wanted the first fan on a thermostat so it would come on automatically when needed.

 

[threejacks]

Any ideas on why my truck has been running so cool since I made the changes last fall?

 

[JOAT]

I wonder if it was running hot previously (delayed thermostat opening). Mine runs near the N most of the time. I don't have a real coolant temp gauge, but based on my readings at the EOT sensor and the temps my coolant heated WVO system reaches, I suspect my thermostat is opening around 190ish, which should be about right for a 205° thermostat. (temp rating is based on temp at fully open). You'd have to install a decent temp gauge to really know for sure what temperature you are running at.

 

[Jcart]

threejacks,

Checkout my Pix below as I have some of my dual fan set up. Will be found in My truck pics.

Set my dual two speed fans (Taurus) to come on either when the AC circut is activated (low speed), or through the temp probe switch, which is adjustable and the probe is in the upper rad hose (highspeed circut). I have installed a three position rocker on the dash whereby I can shut off totally (no fans), or activate by AC (low speed) or automatic based on coolant temp (highspeed).

I do not have an electical schematic set up but have two relays (40 amp) one for each circut. The respective activation circut(s) running to the dash rocker switch so that I can choose which circut (high speed or low) to have activated......

hope this makes sense.

jrc