Hello all,

I've been driving the truck for a bit over a week now and this is what has transpired.

Up to 45 mph...typically a 30 degree spread between EOT and ECT.
45 to 60 mph...30 to 40 degree spread.
60 to 80 mph...up to a 50 degree spread.

I have since uninstalled the BullyDog tuning and found no change in temps. I updated the tuner and reinstalled with no change.

I'm going to put a couple thousand miles on it and do another oil analysis to see if something is wearing abnormally.

As it stands now it runs perfectly...power is excellent, idle is perfect, it starts better than ever, mileage is good and the ECT floats between 186 and 194 degrees.

Scratches head...

I'll report back when I know more.

Donnie

 

To all of my friends,

Please pardon the hiatus. We decided to put 3,000 miles on the new oil and have it analyzed and it took some time to get to 3K miles and then receive the results.

The analysis of the oil indicated one thing...that it needed to be changed. Nothing else...no metal of any type to indicate a pinch point or impending failure that would affect EOT.

Yesterday, the guys at the repair shop extended the appropriate harness and swapped the connectors between the ECT and EOT sensors. The delta remains the same, 25* around town and 35 to 40* on the highway with nothing being towed. It is interesting, however, that the starting point is lower. When the harnesses are connected properly, the ECT hovers around 190*, + or - 2*. With the connectors swapped, the ECT (indicated by the EOT gauge) hovers around 180*, + or - 2*. BUT...the delta remains the same.

Unless one of you have a thought that can send us in a new direction it looks like we're at the point where "remove and replace mechanics" is our only option, expensive as it is.

Please feel free to ask questions...any thought may take us where we need to go.

06Fun

 

At this point, maybe it's time to look into an oil-to-air cooler like the BPD one. It's a very expensive part that I feel most people wouldn't actually benefit from, but it might really work for you and at least you'd have completely separate oil and coolant systems so there's no chance of the oil cooler bursting.

 

The only thing I can't think of is to follow m-chan and check the fan operation. Have not seen those results. The other thing still a head scratched is, what is your oil flow through the cooler? Is there a way to time what goes through the other side. Can you verify the oil line to the cooler and from it are not collapsed? Just an idea, don't know if we can actually verify easily. Is there. A thermostatically controlled bypass to the oil going through the cooler or is the water coolant bypassed? I don't know, it seems one or the other isn't going through the cooler and out the other side. Does no good to verify flow to it, it's what comes out the other side. Don't know if this is helpful, just trying to explore, this one is a head shaker.

 

We have verified fan operation with a couple of tests...the most recent being when the oil temp got to 212 (remember, the ECT circuit is reading the oil temp for now) the fan came on...when the temp dropped back a degree or two the fan turned off.

We have verified coolant and oil flow thru the cooler...we have no way of measuring flow...just verifying that oil and coolant are moving which indicates no blockages.

There is a bypass that we have verified is working properly.

Head shaker is a really good term...

Thanks for your input.

 

I've considered the BPD cooler but really want to figure out what's broken with the factory system...it's nonsensical to me that we can't find the broken part and repair or replace it.

All that remains to be replaced is the low pressure oil pump and front cover (the water pump was replaced a year ago).

I may resort to remove and replace mechanics if necessary.

Thank you for the input.

 

Man o man. A headsheker indeed. Sorry I am out of options here. At th ose oil temps I hope your using a full synthetic 5w40 that is CJ4 rated? Definately severe service and until the oil temp is addressed I would be changing at 3000 miles, not 5000 and testing the oil. What are the oil temps in the pan when the engine oil temps are so hi? Can you verify a metal part coming out of the oil cooler to verify that hi a temp? This would be your best chance of transmitting the actual oil temp is a metal pipe exiting the oil cooler or the housing where the oil temp sending unit is. Must smell like me cooking on the open fire with hot oil. I hope m-chan gives you another look, he seems to have seen and fixed a lot and his experience won't guide you wrong!

 

Interestingly, we took temps some months ago with an infra-red gun at various locations on the engine and found no more than a 10* spread between my engine and a known good one AND it does NOT smell as if the oil is cooking as you suggested.

Back to head scratching...

That's why this is so confusing...based on the temps I've observed via my shop's scanner and the BullyDog GT tuner I would have expected the latest oil analysis to indicate a breakdown in the oil. I will talk with the oil analyzers to make sure they're doing the proper test to check heat related oil breakdown at my next oil R&R.

My next test is to put my Jeep on it's trailer and tow it to Jacksonville...about 110 miles each way and watch the temps closely...I'll make notes and post them for your consideration.

Thanks again for your time.

06Fun

 

Modern oil is designed to withstand a constant 300+ degree use. 250 degrees is nothing to oil.

Josh

 

The EOT sensor is not located at the point where maximum oil tempertaure will occur ............ If you see 250 degrees on the sensor, you most assuredly are getting the oil to quite a bit higher temps within the engine.

 

Problem started after new oil cooler r&r.
Oil temp sensor located in oil cooler.
eot & ect sensors swapped confirm temps.

Perhaps obstructed oil flow thru new cooler?
Oil filter housing not flowing oil?
Just throwing it out there perhaps to trigger a thought from folks who do these repairs more often

 

EXACTLY the EOT sensors is Likly at the Coolest spot

That EOT sensor is right After the Oil Cooler

Its position Allows us to do the ECT vs EOT Test



I still wonder about the front cover and cavitation since it had water ran threw it for awhile. With the small Oiol Cooler passeges it takes Good Flow for the Water pump to be able to Push coolant threw it and Effectivly take the Heat away from the Oil

 

Thanks Benny, I was just wanting to point out that (IMO) the temps from the EOT were high enough to warrant a UOA.

 

Well...uncle. I call uncle...I'm out of ideas.

The only part left unchanged is the front engine cover...the tech noted some damage to the front cover as a result of debris in the system. The wear is apparent on the area that makes up the housing of the pump that encloses the impeller when the pump is installed in the front cover.

This is the only place I can see that some wear would allow for a reduction in coolant flow. I can only assume that the engine oil cooler requires the greatest pressure and is the last item serviced by the cooling system when pressure and flow are reduced.

The problem lies here...it's a $1,200.00 remove and replace guess whether I win or lose.

I'll report back when I feel the need to come off the money...

Thanks again to all who provided input.

 

I hate the position you are in, but it sounds like you are on the right track. I can't recall, but did you ever replace the LPOP regulator?