That's good news. I'll be ordering one or two.

 

BDP does have just the value - thanks for finding that, ordered this morning. BDP does not normally sell those brass valves so they were kind of put off that I was asking for one. BDP did indicate that they include a different rated spring with their kit, that was good to hear.

On my truck, I do see:
- higher overall temperatures driving up a grade, though the difference between ECT and EOT come to within a few degrees as long as IPR/IPS > 2200, specifically the ECT comes up towards the EOT which to me indicates that heat is transfering from the oil to the coolant as a result of either improved oil flow into the cooler, or improved coolant flow into the cooler.

 

Here's the part #'s they said they have no springs. Shipping was $8.95

 

I disagree with this statement. Look at the schematic for the oil system, multiple sources can confirm that the oil system is connected indicating that the 70psi generated by LPOP is the input to HPOP. The reason it does not hydrolock is because of the IPR/IPS on HPOP pressures and the oil pressure regulator on the LPOP. If you have a significant leak in HPOP then your LPOP can not create enough pressure to lubricate the other channels, being the main bearings and turbo bearings.

 

Great find 87! I like the teflon idea.

 

It does look like the reservoir is pressurized. Thanks for making me check.


I'm still not sure I'm following you on your HPOP/backpressure theory. At lower engine speeds, the HPOP flowrate is reduced, but so is the LPOP. And I don't see where the HPOP would use enough oil to cause significant system pressure fluctuations when the HPOP flowrate varies. My guess is the running gear bearings represent the bulk of LPOP flow.


The cooler bypass valve is shown as a differential valve and will open when the dP across the cooler gets to 25 psid. The 6.0 Bible doesn't appear to indicate any sort of absolute pressure value - either upstream or downstream - that operates the valve. Just the difference between those two values.


Unfortunately, I've got no mountain passes I can run my truck over. I hope you get it figured out. When you do, let us know what you found.

 

Agreed.

This is how I have sorted out the schematic in my mind:

Think on it this way:
- the oil cooler and the oil cooler bypass circuits/paths are in parallel
- fluid will follow the path of least resistance across those parallel circuits
- fluid flowing in a straight tube is one thing, fluid encountering 90 degree turns creates significant resistance and not flowing as easily, resistance characteristics change with pressure and volume
- LPOP is pushing the oil down stream at 70PSI
- HPOP is consuming the oil stream at 70PSI
- both LPOP and HPOP are a mechanical and mathematical result of the crankshaft turning, so the ratio between LPOP to HPOP is a constant ratio regardless of RPM
- good chance that the channel resistance from Turbo and Right Bank and Left Bank are fairly constant with varying RPMs
- we know that LPOP and HPOP volume is a result of crankshaft RPMs
- we know that LPOP pressure is controlled by oil pump bypass at 70PSI
- we know that HPOP pressure is controlled by ECU commanding IPR/IPS based upon fuel demands as influenced by the go pedal

The oil cooler bypass valve opens when the output from the flow of oil through oil cooler encounters enough restriction, to make 25PSI difference as compared to the cavity behind the closed oil cooler bypass valve - then it opens, probably momentary and chattering as it balances out pressure across the parallel circuits/paths at lower RPMs.

We can observe that IPR PSI is lower at lower RPMs, that injector pulse width is broad to compensate for lower PSI at the injector, unless someone stands on the go pedal.

We can observe that IPR PSI is higher at higher RPMs, that injector pulse width is narrow because PSI at the injector is high - all because someone is asking the motor to produce significant power through the go pedal.

As RPMs rise, eventually the system is less influenced by oil flow/pressure resistance from Turbo and Right Bank and Left Bank.

Within this system of constraints, I suspect that the oil cooler bypass valve encounters a transition point as the ECU commands higher IPR/IPS - resulting in the LPOP 70PSI being more stable because effectively the down stream of HPOP is being choked down by IPR to create pressure. IPR choking down the volume flow of HPOP to generate pressure would send a shock wave of pressure through the stream of oil flow, the LPOP would compensate by starting to spill off pressure at the oil pump bypass, or relief valve. That is potentially doing a better job of keeping the cavity behind the oil cooler bypass valve at pressure, encouraging it to remain closed.

All of this probably happens in the blink of an eye.

This might explain the wear on the oil cooler bypass valve brass area as it is probably very active at lower RPMs, the rubber seat eventually wears thin - either of which could compromise the ability for the oil cooler bypass valve to close properly - thus allowing the oil to follow the path of least resistance.

Way wicked.

 

The IPR does not choke off or change the volumetric output of the HPOP. It only directs it to either the oil rails or the crankcase, wherever it is needed. It's really not good practice to attempt to reduce the forward flow of a positive displacement pump - unless you like blowing things up.


With this in mind, I can't see the pressure surge you describe.


Am I misunderstanding your mechanism?


I'd still be interested to see if your down-pass deltas remain the same at a higher engine speed.

 

Figure 86 on page 41 of the 2003.25-6.0L Coffee Table Book located in the Tech Folder. Changing the downstream resistance is how pressure is created, if no restriction on output volume then little to no pressure.

 

The original post describes that the difference between engine coolant temperature and engine oil temperatures are influenced by IPR PSI on my truck.

My example is just my truck, others might have varied results caused by other problems.

If I drive the truck up a mountain pass then I am placing load on the motor, the ECU will respond to the influence of the go pedal by requesting more air, more fuel and higher IPR PSI as RPMs raise higher - in order to maintain the legal speed limit. On my truck this is bringing engine coolant temperatures and engine oils temperatures within a few degrees.

If I drive the truck down a mountain pass then there is very little load on the motor, the ECU will respond to the lack of influence of the go pedal because the truck is essentially coasting to maintain the legal speed limit. This results in high RPMs and low IPR PSI because there is no significant fuel requirement because there is little to no load on the motor. This is when I see a broad different between engine coolant temperatures and engine oil temperatures.

 

You are correct - thanks for the correction. IPR does not change output of HPOP - HPOP volume output is a result of RPMs. IPR chokes down the downstream flow of HPOP volume, restricting volume in order to create high pressure. I've edited my posting.

 

Copper.Farm, my high oil temps come when pushing hard and go lower when coasting. Was that a typo that you just posted or is that correct?

Edit: Never mind , my dumb a$$ went back and reread whole post. Mine is just the opposite of yours. My valve will be here Friday am still going to put it in. Will post picture of other one. Won't do it until mid week next week.

 

My experience is different from yours. Part of that could be the conditions which were 20'F outside as I conducted my experiment. As I write this, I am realizing that my problem is compounded by another issue....

If I drive down the mountain pass then the coasting and lack of load on the motor are creating as high as 30'F difference between EOT and ECT, with coolant being lower than oil, while maintaining 70Mph. Indicative of cold air flowing across the engine cooling system under light load, yet we would think that the oil cooler would transfer that coolant lower temperature efficiency to the oil - not so as the differences between oil and coolant are climbing. I see low IPR Psi as I drive down the mountain pass because there is no significant load on the motor.

As soon as I turn around and head up the mountain pass creating load on the motor while maintaining the legal speed limit (70mph) then I see my coolant temps rise aggressively and my oil temps rise much slower than the coolant temps. Within a few minutes of motor under load, the temperature difference has diminished to only a few degrees. I see increased IPR Psi > 2200 as I'm driving up the grade due to load on the motor.

This leads me to think that the oil cooler bypass valve is closed under higher IPR Psi and that the oil temperatures are actually warming the coolant as a result of the oil cooler efficiency. It was also 20'F outside.

I think my problem is compounded by an open thermostat allowing the coolant system to drop below a maintained operating temperature, being more influenced by ambient temperatures.

 

Same here - I will look at mine some time next week after a new valve is delivered. Also ordered new thermostat. I think I'll first replace the valve, then test again - followed by replacing thermostat and testing again.

I still think that at the moment, my oil cooler is only being utilized when the motor is under significant load.

 

You can't take all of this on a one for one ratio. The specfic heat and transfer of oil is different then coolant.