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New Oil Cooler does not correct the problem

2K views 14 replies 3 participants last post by  amxgilligan 
#1 ·
I had a new oil cooler and EGR delete done about two months ago in hopes of narrowing my EOT and ECT deltas below 10 degrees. Most of the everyday driving and pulling my bass boat I can keep it down to 12 degrees difference. Today, 95 degrees outside I pulled our 29' fifth wheel down the interstate with a few moderate (but not bad) hills. At the top of the hill I got 238 EOT and I was only going 60mph. I am afraid I cannot make it up some of the more steep and long hills in East Tennessee later this year. My EOT and ECT deltas have been all over the place but today towing I was getting up to 30 degree differences !! Any advice would be appreciated.
 
#3 ·
My ECT was all over the place with deltas as high as 30 degrees but when I approached the 238 EOT I would say the ECT was around 225 give or take.
 
#4 ·
I think I would start looking at the cooling system... a proper flush and check of the rad by a rad shop, look for restrictions in hoses, maybe water pump issue. Look for restrictions or external blockages in the other rads up front, bugs packed into the A/C rad. Remember the engine rad is the last one in the group of rads to receive air....it's at the back of the pack. make sure the clutch fan is working correctly. The truck should sound like a jet engine when that fan is running at full speed.
 
#5 ·
My mechanic did a full flush about 2 months ago. He is supposed to be checking the fan to make sure it is working properly. I have never heard it come on even at 240 EOT. He said he forced the fan to come on and the actual fan works but that does not mean that a sensor or something is not triggering it properly. What temp does the fan come on at ?
 
#6 ·
This is a cut and paste from one of Bismic's old posts:

"Engine temperature is not the only parameter that the PCM monitors to determine cooling fan operation. This is the reason that you will see some variation in engine temperature as it correlates to fan operation. The operation/description of the FSS (Fan Speed Sensor) from the PC/ED manual has a fairly good explanation as to how the system "thinks". This is not your traditional engine hits temp X and the fan clutch locks up. The fan speed sensor is a Hall-Effect sensor integral to the vistronic drive fan (VDF). The powertrain control module (PCM) will monitor the sensor input and control the VDF speed based upon engine coolant temperature (ECT), transmission fluid temperature (TFT) and intake air temperature (IAT) requirements. When an increase in fan speed for vehicle cooling is requested, the PCM will monitor the FSS signal and output the required pulse width modulated (PWM) signal to a fluid port valve within the VDF."
 
#7 ·
If I'm towing up a steep hill and my temps are rising fast and getting towards the max ranges how much will a properly operating fan offset those temperatures and keep me from overheating ?
 
#8 ·
The fan is extremely important. If you took a brand new 6.0L truck (if one was available) with everything working perfectly as it should and unhooked the fan, the truck would overheat on a hot day towing up a grade.
 
#9 ·
I have never heard my fan come on even though my mechanic says he has forced it on through the computer. I know that bisimc's post details the specifics of what actually triggers the fan to come on but I have been told that the temps are already pretty high like over 230-240 EOT before any fan action occurs. That seems high to me.
 
#10 ·
Just had my mechanic come by with his computer and hooked up to the truck again. He was able to force the fan on with the PC and you could definately hear it running loudly. Problem is should it not come on at 230-240 EOT ? I don't know what to do next. I am supposed to pull a camper in two weeks in the mountains and I know if I do I WILL overheat.
 
#11 ·
This is a cut and paste as well from another user:


I simply cut back the wire insulation cover on the cab-side fan wire connector at the top of the fan shroud about a half inch and used a yellow Posi-Tap connector to “T” into the dark blue wire. (PIC 1) I then ran a length of 16ga. wire long enough to reach the customer provided pass through wires (r,w,b and black) taped over on the wiring loom above the master cylinder. I connected the wire to the blue pass through wire with a take-apart quick connector so that it is very simple to pull apart the wire to do work on the motor or air delivery components.(PIC 2) Inside the cab I located the blue pass through wire (just above the emergency brake foot pedal) Extending that wire about 2', I added a simple 2 post toggle switch (for a ½” hole). To the other post, I added 2' of wire and terminated it on a 1/4” ring/eye electrical fitting.

At this point it made sense to check the integrity of the wiring assembly with an electrical meter. With the truck running, the meter from the ring fitting, to a ground point anywhere on the metal dash support bar exposed by removing the dash fuse panel cover (seen in PIC 3), it should read somewhere over 12 volts (whatever the alternator is putting out) with the toggle in the on position. And, it should read zero volts with the toggle off. If that works, then it is only necessary to connect the ring-eye to a good solid ground to complete the mod..

I found the small black screw at the lower left corner of the open fuse panel compartment to provide a very good ground spot. (PIC 3, black wire) The screw mates with a copper bracket that sandwiches the steel dash support bar. I located the toggle itself just to the left of the steering column, about an inch or so, in the part of the dash that sticks out above the fuse panel cover.(visible in PIC 3) It's out of the way, yet still easily accessible. The red wire (seen in PIC 3) is the extension of the blue pass through to the toggle. (red is simply the only wire I had on hand).

That's it, very simple and inexpensive. At least one way to do it.

But, I have some comments or thoughts and notes on this mod, now that I have made it.

1). I suspect that the manual override should probably be used sparingly. Generally, the PCM controls the fan speed based on parameters for the balanced needs for cooling and the horsepower requirements of the fan. [I read in a tech thread that at full fan engagement it can take up to 27 hp to drive the fan whereas it may be as low as 1 hp or less at the lowest engagement level of the viscous clutch.] Whether or not that figure is right, I think everyone can certainly feel some sizable drop off in acceleration power when their fan is fully engaged. The majority of owners who don't have detailed temperature monitors and gauges probably get along just fine with only the PCM fan control. Those of us that need to monitor everything tend to think we can do better than the PCM! I think the only real advantage for manual control is that we can potentially foresee upcoming events that the PCM can not possibly know. (like that there is a steep grade ahead or that we are terminally stuck in slow traffic at high outside ambient heat and aren't going to need that much hp.)
2). NOTE: Once you have made this mod you will not immediately notice fan engagement at idle in your driveway. But on the highway under throttle you should notice a substantial sound differential, especially on acceleration.
3). The mod will likely cast a P480 soft code, mine does.
4). In the toggle OFF position, the PCM control of the fan should not be effected by this mod. Therefore, the flexibility to control the fan engagement “full-on” manually is worth the effort, I think.
5). I put a length of protective flex tubing over my wire in the engine bay to protect it against heat and possible short. But that is probably superfluous since if the wire did ever ground out all it would do is engage the fan, which should be fairly obvious to the driver and easy to fix on the road by just disconnecting the blue wire tap at the“T”.
6). I think that there is an advantage to a manual switch, if for no other reason, to be able to reassure yourself periodically that the fan clutch is still operating correctly.
7). All of the talk in this thread of trying to develop an adjustable manual fan control is in my judgment, overkill, as the PCM can more likely do a better job of controlling variable fan functions in most instances. Certainly better than I could.
 
#12 ·
#13 ·
Phil G- I don't see any specific pic1,2 or 3 that show the wiring. I see all of your mod pictures in the link. Am I looking in the wrong place ?
 
#14 ·
That's just a copy paste from another forum I found quick using google, the pics won't transfer to this site. It's not my mod.
 
#15 ·
Phil G.- I took your advice exactly and bought the BPD 7.3 fan clutch and adapter bolt and the fan works perfectly now. I towed the last three days up steep hills and never got over 214EOT !!! Thank you for the advice. Pass the word.
 
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