I purchased the Dashboss over the winter here in Atlanta and it has been very helpful with monitoring key engine metrics.

It was unseasonably warm here for a couple of days recently. I was surprised to notice the warmer temperatures having a pretty dramatic impact on my ECT / EOT delta.

My commute is primarily by highway. Once warmed up and running a consistent speed of roughly 70 MPH, I noticed these differences:

@ 26 degree ambient temperature - 190 ECT / 205.2 EOT (this tracks with the rest of my winter readings, 15 degree or less delta)

@ 60 degree ambient temperature - 190 ECT / 220 EOT (30 degree delta)

Clearly my oil cooler may be failing, but my feeble mind was very surprised at the impact outside air temperature has on internal engine temperature. If anyone has feedback on this it would be greatly appreciated.

 

Wow, if you still have an EGR cooler be carefull with spreads like that.

I notice about 2 degree warmer temp difference @65 with ambient in the 80s versus in the 20s.

Like 190/197 @ 20 or 192/199 @ 80

 

You were likely using the HEAT @ 26* ambient ! And although the ECT was still 190* all that extra heat being removed help keep the oil cooler

 

@Bullitt390 - thanks for posting your results this helps me better understand where I compare. I also appreciate your comments on the EGR (I still have one in place)

@Misky6.0 - a very solid point about my use of heat and its impact on the overall readings. I was not even thinking in that direction, so many thanks.

 

At those cool ambient temps, fuly warmed up you clearly have an oil cooler issue. Do you have an EGR delete or a block off. If its just a block off, then you are still pushing coolant throught an EGR before the oil cooler and that can be contributing to your delta's being so high. Also, what is your IAT, oil and coolant temps at cold soak, they should all be within same temp +/- a degree or 2. If not you have a bad sensor and that could be contributing?

 

@mhoefer - truck is completely stock. I have owned it since new. Good point about the cold soak, I should have put details in my original post that this is within norms.
I am not currently tracking IAT (Intake Air Temperature??) but will look for that setting on the dashboss and report back here.

I greatly appreciate everyone's solid advise and assistance with this.

 

@mhoefer - on my way home tonight at 730 pm - 190 ECT 204 EOT 55 IAT
This was at about 67 MPH steady on highway after truck had fully warmed up.

Dealer where I bought the truck who has done the little mechanical work I've needed quoted $3K for oil cooler / ERG / clean turbo. I am having serious doubts about putting $3K in a 2005 vehicle with 257K miles. Is this the beginning of the end? Wonder if it's time for a trade while it's still running good. Thoughts?

 

$3k sounds high. If I were going in there, I would NOT be replacing the egr cooler with anything but an EGR delete. At the very least(only if smog regulations are very strict where you live) I would be doing a bulletproof EGR cooler. Regardless, to do the oil cooler you have to remove the EGR cooler and the turbo, so I think your dealer is trying to take you for a 'ride'.
An OEM oil cooler is about $300. Labor for a pro should only be 4-5 hours. Even at $100/hour you're only at $800. Deleting the EGR would be $100 or so out of your pocket and should not be any additional labor from your mechanic, since it comes out anyway for the oil cooler. If your turbo hasn't been rebuilt it's probably due, but even that is only $165 for the kit and maybe 1 extra hour labor considering the mechanic already has the turbo out for the oil cooler.
So really, a good price is more like $1200, $1500 max. If the truck is in otherwise good condition and you are enjoying not having a care payment or lean bank account then I say do the repairs. The most I would pay is $2k, at the very most. Anything above that is your mechanic trying to take advantage of you.

 

IMHO 3K is a little high for that job from a dealership but not outrageous. It's a lot of nuts and bolts to turn but nothing really difficult and NOT worth selling a good running truck for. You can probably find a good independent shop with recommendations from the Georgia chapter FTE guys. You can purchase the OEM parts yourself fairly cheap. I think Ford offers a kit for oil and EGR coolers together although I wouldn't replace it with an OEM EGR cooer.