Join Date: Jul 2019
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07 dt466 egr overheats on freeway
New from Tucson and hoping someone can help with this issue.
Semi-retired mechanic with over 40 years wrenching. Still learning every day! This International 4300 only overheats on the hiway at 65mph or over. After checking for combustion gases in coolant (none), coolant flow, temp sensor function, codes, overheat history, leaks, t-stat function, viscous fan drive, belt slippage, radiator temp differential, exhaust and intake restrictions, missing air dams and air seals around radiator, and repairing or replacing as needed, we still had the overheat! Fuel settings and all parameters in programming at factory settings. It runs great! Desperation drove me to theorize that egr cooler was plugged with soot, thus allowing more combustion heat to develop, since one function of egr is to lower burn temps. Pulled egr cooler, it was indeed full of carbon. Cleaned, reinstalled, no more overheat! Truck had noticeably less power, but enough. Again, scanner showed all fine.
That was about a year ago. Last week, driver reported it overheated again on a run back from Yuma. As before, he backed off til it cooled, from 75 to 65 to 55, and came on in. Did a quick check of fluids, fan, combustion gas in coolant test, nothing. Took a morning run uphill at 75 mph and temps just keep on climbing! 55 or lower, all's fine. Monday or Tuesday, I plan to pull the egr cooler and check it, first.
Any ideas? I'm open to all suggestions, thanks!