Hi everyone, need here! I recently noticed on my truck that my oil temp was running high, I would go down the interstate at 75 mph and the oil temp would get up to 215-218 while my coolant temp would sit around 192-196. So, I took it into the shop and was told it was most likely a bad oil cooler and had it replaced 2 years ago when I had my injectors and gaskets replaced along with my egr deleted. So, got the truck yesterday, going 60mph down the highway, truck ran an oil temp of 192 and the coolant at 188. Was great, but later on once I got to the interstate going my 75 mph, The oil temp jumped to 209 and my coolant sat at 192. Not sure what the deal is, was told the oil cooler was replaced and wanted some input on what else I could be looking at. I currently have 5w40 synthetic oil running in it if that helps at all. I have an EDGE CTS tuner on it and tuned it back to stock mode, but oil temp still jumps up to 209 and coolant remains around 190-192. Any advice is greatly appreciated! Thanks in advance!!

 

Did they do a chemical coolant flush before doing a new cooler? The oil cooler is great filter, they could have disturbed some of the crud that plugged the first one and plugged the new one.... wouldn't be the first, won't be the last.

 

What does the ECT, EOT and iat read in the morning before you start the truck?

 

Was an OEM oil cooler used or one of the aftermarket high flow units?

 

Honestly, 209 at 70 mph is about normal if you ask me. You cannot gauge the health of the oil cooler at that speed. There are so many variables that can affect the old "delta value" test making it sort of....inaccurate.

For example; lifts, large tires, bed covers, bed caps, speed, gear ratio, SRW/DRW all have an affect on the resistance the engine has to overcome, which all of this it makes into heat.

Last month I did a delta value comparison between my truck ('05 6.0 4x4 5R110 CCLB DRW 4.10) and a friends truck ('05 6.0 4x4 5R110 SCLB SRW 3.73). Both trucks had brand new oil coolers, fresh IPR, fresh VGT cleaning, new STC, ELC coolant, coolant filters, ICP/pigtails, new fan clutches ( I did the work on both, two weeks apart)... In other words, both trucks had no problems at the same time. The only differences are mine runs a stock 2005 EGR cooler and his has a BPD cooler on it. He runs rotella 15w40 and I run T6 5w40. Mine has the stock DRW size tires and weighs over 8100. His has 285 tires, no lift and weighs about 7200. My truck turns about 1950 rpm at 60 mph and his is around 1500.

At that time, going 60 MPH for approximately 22 miles after getting a good warming cycle on both resulted in my truck showing an oil temp of 204 and his with 200. At 70 mph on the way home, I hit 210 and his went to 203. I also was at 2300 rpm and he just barely broke 2000 at that speed.

What I'm getting at here is that each truck is different. You really need to change an oil cooler and see what the result is before you can compare anything to give you an indication of a clogged cooler. I changed mine after 1 month of ownership simply because I didn't want the hassle of rupturing an EGR cooler on the road.

 

OP: The oil cooler test is 65 mph (unloaded truck). Also for valid reading you should have ECT greater than 189 degree's. Faster speeds will give you a higher delta reading and lower speeds will give you lower delta reading.

I just tested mine the other day at 65 mph and I get 12 degree delta (191/203). My cooler is getting ripe for replacement. Even with this spread I towed 13K fifth wheel from Arizona to Florida without any issues. I kept my eye on the EOT and it stayed below 230, except two times during the trip for just a few minutes each time.

 

The test is at 60 mph with no hills and
With the engine warmed.

That being said, I have a brand new oil cooler in mine and get 10-12 degree deltas sometimes.

 

The test is 1800 rpms. The speed can vary depending on gears.

 

Listen to this guy first....

 

With the egr deleted the delta is not that important as long as the oil temp stays 230 or less, 250 the truck will defuel. The delta is used to determine how much coolant is getting to the egr to keep it from overheating and bursting as the coolant goes through the oil cooler then to the egr.

 

^^^^ this is very true with a delete in place^^^^ but I would have thought that a new cooler would have gotten you a closer number.

 

The problem is all components of the cooling system have to work together correctly for
proper heat exchange to take place. Any one part fails to deliver properly affects overall
efficency of the system. There is just too little margin for error in Fords design.
The baseline tests are run under a specific set of conditions. All ready covered by others. Anytime you exceed baseline conditions you have to compensate baseline values for the amount of change. As far as I have found there are no Ford published tables or charts for those changes. Rule of thumb only.

 

 

Ford would not publish numbers for an illegal system. The job of the oil cooler in a non-egr system is to maintain oil temperature, period.

 

The test is at wide open throttle.