Hey all. My 2005 6.0 (studded, deleted w/ cat 1 ELC, 167K OD miles) recently sent a warning to check gauges and threw a wrench light as I was towing my 33' fifth wheel trailer while ascending a grade in Yosemite NP. It happened twice and I stopped in the middle of the highway to let it cool down. I checked my dash boss at one point and it showed the oil temp at 252*. I parked the trailer at wife's uncle's house, then performed a check to see oil cooler health by cruising on flat ground at 60 mph unloaded and watched oil and coolant temp differential. It only showed an average of 5* differential. Even with the test, I'm still assuming that the oil cooler is faulty as the oil temp rose so darned high and sent the warning to check gauges and wrench light but am a little confused as to why the temps were so close while doing the 60mph unloaded test. Does the delete change that parameter? I took the truck to a shop (that doesn't do mechanical work on diesels anymore) and the mechanic checked the code for the wrench light, which came back indicating high differential in oil and coolant temps and two glow plugs showing fault. I thought about trading the truck in for something newer as I figured that the money spent to change the cooler could go toward a newer truck, but am hearing that deleted trucks are no longer tradable due to later federal laws, etc... Input please?

 

Probably partially clogged, although some don' believe that's possible.

I would do a backflush with air a few times, water pump removed, and see how it does. Since you ran ELC, there's more chance of a particle clog at the inlet than anything else. But, of course, the flat road 60mph test won't show for that.

 

Thank you! If you know of a reliable reference guide for this procedure, i.e. youtube, etc, I'd sure appreciate it.

 

This was a good write-up about the issues and later the backflush procedure was added.

There is a kit you can buy, or just do it with a hose. Google and you can find many threads and a few videos.

 

Was your fan roaring at the time of the high temps?

 

OldFordsnstone, I recently had a similar experience towing our camper (first time towing with new to me truck) up Mont Eagle in Tennessee. According to my Edge CTS3 my delta was close to 90* and the oil temp was over 290* The truck lost power but didnt trigger a wrench or code for temp difference. Earlier in the trip I had a code for something related to boost but after clearing it never came back. Anyway I said all that to say I got to looking into flush kits and came across a kit from Fixur6, it was a little pricy but you can leave it on your engine and flush it anytime you want/need to with out having to remove the cover and reinstall the flush kit. First time flushing it I was surprised at how much trash came out and I'm not convinced that the cooler wont eventually need to be replaced anyway. My deltas are still a little out of range but get better after flushing. I have some other work planned in the next week or so and will flush the entire coolant system before going in for "bullet proofing". I don't know if we can list products on the forum and I am not plugging his product but I have had great results from it so wanted to share.

 

I would try several times.

 

So far I have flushed three times until it comes out clear, each time I get a little less out of it and my deltas get better so I'm definitely gonna keep after it.

 

It's tough to get all the debris out of the "loop" when backflushing.

 

I don't believe you can have a correctly measured Delta of 5 degrees with a clogged oil cooler. I'd bet a house payment on it. I'd take these steps first.

1) Change the oil cooler sensor. It's possible to read correctly at low temps, but read way too high at high temps. I had a coolant temp gauge do the very same thing, and its the same gauge as the ECT. Verify the actual reading is correct. Easiest way I know to do that is to change the sensor.

2) Check the oil cooler bypass valve. From my own troubles and learning, I believe the oil cooler bypass valve opens somewhere between 70 and 80 mph without a load. When towing, the oil demand increases and it will increase oil demand to a point where the oil cooler bypass valve opens a lot. It could be opening wide under peak towing demand and sticking open. Pull the oil filter cap, and pull the oil cooler bypass valve and inspect. Replace ($30) if necessary. The kit does not come with a new spring. I do not know how to check that spring to make sure it hasn't softened with time.

3) Check for jumpy data from the ECT sensor. This would suggest a short of some kind short in the pigtail/wiring.

Try the three things above first. Cheap and easy.

If those three don't give you more info to solve the problem, I'd start backflushing and then seeing if the delta changes when under load. Problem is, you really need to be towing to replicate the situation when the EOT hit the roof.

By the way, I've fought with EOT temps on my truck. It stays parked (almost) unless I pull the camper. I've run with EOT at 252 before. I run synthetic oil, so I wasn't worried about oil break down. My delta then was 60. My delta at 60 mph steady state was 30. Because this was my third oil cooler, I relocated the cooler behind the passenger battery with the BPD kit. My Delta's now max out around 13 while towing and my next oil cooler job will take 30 minutes.

 

It's hard to recall, but I don't think so. That's a good question. But I did take it to a shop to pull the codes and he came up with high differential between coolant and oil temps. Still though, I don't remember hearing the fan roaring. You've got me thinking here. Funny thing is, going 60 unloaded on flat ground the differential was around 5*. Hmmm

 

I'm beginning to doubt the code read showing too high of differential oil and coolant temps. I wish I would have looked at the scanner when the mechanic was running for fault codes. I tested the truck after dropping the trailer at 60 MPH, flat ground for 5 minutes and came up with a differential of 5*. Hmmm

 

If there is no EGR valve plugged in, your cooling fan will not operate correctly. Russ

 

Back flushing is merely a temporary band aid -- ultimately you need to replace that Oil FILTER (cooler).

Ford's (International's) design on the 6.0L isn't all that hot, it's far worse on the 6.7L where dirty oil (from the pan) goes right to the Oil FILTER (cooler) first before hitting the actual filter. They're simple to replace on the 6.7L thankfully, mucho harder on the 6.0L.

 

The EGR is in fact plugged in. The cooler is in the garage and was bypassed and the exhaust port plugged.