Would it stand to reason then that the egr coolers act as a heat sink when there is no exhaust flowing through them (egr valve closed). So the constant coolant flow through the coolers is radiating enough heat to keep the temps a few degree's cooler? Eliminate the coolers, now temp is only controlled by the thermostat, some losses might occur through the heater core as well. Just throwing idea's out as I noticed the same thing after my delete.
pretty much my thinking too.. surface area of a non heated EGR would absolutely cause dissipation of heat.. there ain't no way around that.. maybe as much as two degrees I'd wager.. the heater core does the same, which is the reason it's an old school trick to turn defrost on high and highest heat when you're overheating..
I have and EGR delete kit, including elbow in hand, but I'm on the fence whether to install it or to use plates and reroute the coolant lines.. either way, though, this is a little plan that has occurred to me:
there is an inline valve available on the market that is temperature sensitive.. it would be nice to have that on the old egr coolant feed- have it open and route coolant through an additional heat exchange if it reaches the temperature the valve is rated for.... so, if the valve is rated for, say, 200*, if the coolant reached that point, you can add additional heat exchange surface and drop likely three or four degrees pretty quick with that rig, as you'd be introducing the cold coolant trapped in those lines.. it would also close back up after the valve went back below 200*...
I did this with an auxiliary transmission cooler on a dodge- i didn't want that oil running too cool, but i did want the capacity if i was towing and where trans oil temps go over 190*.. (it would never break 160* DD w/o load).. I would reach 190, and the valve would open.. I would then maintain 190 w/o any struggle whatsoever...
yup.. when I get a chance, this is going on her..