I have a 2005 6.0. I installed a new egr cooler and oil cooler in 2010 @ 160,000. Then in 2012 @ 194km I installed the coolant filter and switched to ECL coolant as per forum discussions. Truck has been working well up until this past weekend. (Also I deleted EGR but the EGR cooler is still in place and allowing coolant to flow). When hauling my 15,000 lb boat the wrench came on and I noticed the temp of the oil was up to 235 while the water was only or slightly less (210 not 100% sure). Within a few minutes all temperatures returned to normal.

After unloading boat , truck cooled and light went out. Towed all the way home, no boat, but a heavy trailer. Light did not come back on and temperatures looked fine.

Got home, scanned and found code P012F

Is it possible that it was just an anomaly? ( I know wishful thinking)

Is the oil cooler and egr cooling in series?

I am going to look into changing the oil cooler but owing to the fact I am not using the Egr can I same some money by not replacing the cooler?

 

did you scan it to see what triggered the wrench light? could be an over/ under boost scenario too.

the oil temp is high, but remember the Delta rule is a warmed up engine, on LEVEL ground and Not towing a boat that weighs XXX???

also please edit your post to tell us what the coolant temp was....

 

You said you deleted the egr but left the cooler in place (stealth delete?), or did you mean you left the EGR valve in place and (hopefully) plugged in?

The EGR Valve needs to be plugged in (electrical connection) even if it is just laying there, or your fan won't operate properly...

You should have had a pretty high fan noise level if Oil was 235 and coolant above 210, do you remember hearing it?

 

I have the valve cavity plugged and the egr is sitting above it plugged in. It opens and closes but does nothing.

I do not remember hearing the fan, everything seemed normal sound wise.

 

The EGR cooler is after the oil cooler with respect to coolant flow. As oil cooler gets clogged, less coolant flows to EGR cooler so EGR cooler overheats and ruptures. Deleting the EGR valve will keep the recirculating from happening, given the intake porting is plugged (not just a plate covering the EGR valve hole). The EGR cooler longevity is still subject to the coolant flow from the oil cooler.

 

What are you using to monitor your temps with? If you don't have something like Torque or SGII you might want to get something set up. My preference is Torque as it is cheap and easy to use and you can set up your own alarms, do data logging (nice for a situation like this so you can go back and analyze), I've got a gauge set-up that tracks the differential in oil to coolant temps. One thing I track is fan RPM -- if you were to see a demand for high fan speed and not see it, that could be one of your issues...

Before you go too far you should do the unloaded 65mph test, then see what your oil to coolant spread is. If you aren't familiar with that: you get your truck fully and I mean fully warmed up, then drive it at about 65 on the freeway on flat ground, some say for a half hour but if you're good and warmed up you will be steady-state pretty quick, so maybe 15 minutes.

Compare the biggest spread between the two (oil should be higher than coolant). If you are pushing 15 degrees difference in this test, your oil cooler is likely plugging...

Good luck!

 

Why is that, if there is no hot exhaust side, what would make the cooler fail? It should be fine even if there was no coolant flow

Now that would mean there's none going through the oil cooler, but I don't understand why the EGR cooler would fail due to just ambient underhood temps...

 

Doesn't the exhaust come out of the cyl head, thru exhaust manifold, up the y-pipe towards turbo? EGR system branches off y-pipe between exhaust manifold and turbo, so unless blocked, exhaust gases follow that route from the head and go thru EGR cooler and into intake. The EGR cooler would be seeing exhaust temps. The EGR block off plug that is installed would be stopping the recirculated exhaust gas from entering the intake side of the intake manifold.

 

X 2 on this!!! Numbers are evidence, not speculation (usually). Do the test, then report back.

 

I believe that is right other than if there is no flow (exhaust) through the cooler (its outlet to the intake is blocked) then there should be no extreme heat?

 

With EGR cooler connected directly to y-pipe, I'd expect the EGR cooler to be about the same temp as the y-pipe itself from the heat transfering through the metal bodies. I'd also expect the air in the cooler be about the same as the exhaust, tho maybe not see the same peak temps (extreme). This is a thermodynamic situation relative to heat transfer, not my can beans, but the cooler if connected to y-pipe, is gonna get mucho hot-o

Don't want to high jack the thread, hopefully the OP's test...Gauges + 65mph test < 15 degrees... Is successful!

 

Soooooo..........what is a PO12F code?

 

Means the oil to coolant temp is out of range. Googled it... my guess is it was set at 235 degrees, fan kicked into high and cooled the truck. At 253 de-fuel occurs to cool the truck. OP probably needed to downshift or wasn't using tow haul?

Either way, probably another plugged oil cooler or at least it's close to it, 25 degree spread with EGR delete would be near my limit of changing it out. The 15 minutes on level ground would be the big telling numbers. I'd be careful towing a big load on hot days and easy on the throttle those times I towed big hills. Real number to watch is 253 after the EGR is deleted as the 15 degree spread would be the number for a truck with EGR to prevent a rupture. But still, a 25 degree spread is a good spread, towing I'd be a little nervous at 25 over coolant and make sure to down shift and ease up.

 

Thanks, I could have found it but was lazy. I'm familiar with a lot of the common codes but had never seen that one pop up in the forum.

 

Thanks for all the great information. Regular driving seems to be fine; max delta of 12 degree C. I am concerned about hauling as we are planning a big trip to the north channel (Killarney) this summer and I would hate to find myself on the roadside.

I run a scangauge and monitor the oil, tft, coolant and fcim voltage. My wife uses the truck as a daily and she monitors the gauges closely. She tells me that 12 is the norm.

I also have the torque app but had only used is on the truck to pull codes. (forgot the scangauge would do this)

I will try the test this weekend on the way to the cottage. If I do end up replacing the cooler I guess it would be prudent to change the egr cooler as well. I just hate the added expense…..


Data from last summer hauling from Toronto to Kingston

Oil 225F
Coolant 210F
Tranny 184F