On my truck - pretty certain that the EGR is not ruptured and that the Oil Cooler is not ruptured .... For what it is worth, this is my experience testing the temperature differences with and without the over drive .....

As I ponder the temperature differences on my own truck I am trying to figure out ways to not spend the funding for the bulletproof solution - though I see how it would solve my concerns at an expense.

With my truck I see nearly neck and neck temperatures while the motor is under load and wide temperature differences when not under load. I live at the base of a mountain pass so it is easy to monitor the temperatures driving up and down the altitude changes of the pass.

After reading hundreds of forum pages across multiple boards, I decided to test my own hypothesis - that the problems are more than coolant, more than the oil cooler which are discussed so frequently.

This morning I started watching fuel consumption as I drove up the pass and to my surprise I saw the injector pulse width was larger in over drive as I was allowing the motor to lug down, vs. being smaller as I was in direct drive while allowing the motor to use the upper torque band at higher RPMs. Then I figured it out, the ECU/FICM are altering the injector pulse width as more oil volume is available at higher RPMs. Looking at the schematic for the lubrication system, the motor is designed to provide oil volume based upon RPM, then bypass or bleed off that volume to maintain presure as commanded by ECM with IPR / IPS.

What I was able to prove for myself today is; as long my truck has:
- IPR < 1400psi then the difference between oil and collant temperatures are increasing to as much as 30'F
- IPR > 1600psi then the difference between oil and coolant temperatures are slowly descreasing, slowly
- IPR > 2200psi then the difference between oil and coolant temperatures come within a few degrees within five minutes

As a complete system, I think the oil cooler bypass is subject to back presure created by the HPOP at higher RPM as IPR increases Presure - so at low IPR psi the oil cooler bypass seems to be engaged and at higher IPR psi the oil cooler bypass is not engaged and oil is flowing through the oil cooler.

Potentially my oil cooler bypass valve is worn out. 04 with 200k ZF6

Thoughts?

 

You won't be the first to have that happen,but the only problem is you have to buy the whole top assembly. Call Diesel Redemption and get a used one. That's what I'd do if it was mine.

 

Me you and Freskan6.0 are having the same problems it seems. If I push mine hard ( 70 - 80 mph for 30 plus miles my spread gets 30+ slowing down to 50 - 55 temps come within 8 or less. No oil in coolant and everything else is fine. Replaced a ruptured oil cooler on mine about 10,000 miles ago. Was getting ready to do it again, but this has caught my attention. I wonder if you can buy the bypass valve at bullet proof diesel as per Freskan6.0.

Edit; Coolant temps never get over 198 - 200

 

What are your MAX oil Temps at the high speed driving?

 

As high as 240

 

Yeah that's a concern. I would definitely be concerned. I'd definitely check that bypass valve spring assembly.
Do we know if it's offered separately yet?

 

Freskan6.0 said in his thread he was going to call them tomorrow. I will also. Will do a search later tonight to see if it can be done. If not I will replace the assembly before I do the cooler. I read a few places that says you can't replace just the bypass valve. Never thought about it causing this problem but it makes sense.

Edit: I want to add that I have a welded EGR delete.

 

I would think a smaller FPW value at higher RPM only stands to reason. If the engine is going to provide fuel every piston cycle, and the pistons are cycling at a higher rate due to higher crankshaft speed, the fueling interval would go down.


My understanding is that the LPOP only feeds a reservoir the HPOP pulls from - the HPOP inlet is not pressurized by the LPOP system. With this setup, I'd expect that a surplus delivered by the LPOP would be recycled back to the crankcase. It would also make the LPOP and HPOP systems essentially independent.


There's a difference between "under load" and "high RPM" - they are not necessarily equivalent. How about downshifting into 3rd gear on your way down the pass - you can then determine if the delta is "load related" or if it is actually RPM related.


I can't help you much in your current predicament, but I would guess that your deltas are RPM dependent and not necessarily load dependent. I am interested to hear what you find if you give it a try.

 

Here's a guy that found a problem and made a new one from teflon. He hasn't updated yet to see if it held up.
here's the link to his blog with pics: WA0UWH - Electronics & HAM Radio Blog: FORD Rant - Oil Cooler Bypass Valve - is a non replaceable part.

 

Mine has been in that range also, with no loss of fluids.

 

Thanks 87 I read that. I will contact him to see how it held up. I also found this.

 

Packagerjr I feel that when you push a f250 at 80 it's like pushing a brick through water. There is a lot of resistance even empty and your temps build. What you said makes sense. You just get to the higher temps quicker with a load. Running around all day I never have a problem. It's just when I push it hard for a period.

 

I did see that also. Makes me want to check mine now. I had it apart 65000mi ago and it looked fine. My oil temp isn't as high as yours but I noticed it is a little higher than norm when towing pulling grade. But then other times it's cool as the coolant temp. Now I'm wondering if mine is starting to stick or leak.
Looking forward to hear what you find.

 

Hello!!! Look what I found. Will be calling in the morning.

 

BPD does have just the valve. Guy couldn't find part # but says they have them. $20.00 plus shipping. He's calling me back with part #. Will post when I get it. At that price it worth a try.