DT466 Major Oil Leak - Can't find it!

BDKB

New Member
Thread starter #1
I have a 2006 DT466 7.6L shuttle bus that my church and daughter's BBall team uses all the time. We seem to be losing a massive amount of oil (1 gallon every 500 miles) on recent trips. Took to Int'l dealer, said there was a crack in the oil cooler gasket and oil cooler itself. Replaced, and oil pressure held for two trips. Now we are back to losing lots of oil. It is NOT burning oil at all, we steamed the engine and there is no VISIBLE oil spewing out of the engine during high rev idling. There is also no visible leaking of oil around the rear main seal. The one thing that is visible, is that the ENTIRE undercarriage has oil all over it. It appears to be coming out of the vent tube however sitting still we cannot duplicate the problem. Only when we get the bus up to 65-70mph does the oil loss occur............PLEASE HELP US!!
 

r3gulator3

Well-Known Member
#2
You could possibly have massive blow by. I would get the crankcase pressure checked. Also the rear structure could leak. Valve cover at the back of the head. With out looking at it I'd just be throwing darts at the wall.
 

r3gulator3

Well-Known Member
#4
Had a 444e Navistar that had a crack in the piston had massive blow by that coated the under carriage like that. Did a compression check and everything appeared fine. Had 8" of blow by at idle and blew the water out of the slack tube under load.
 

mndriver

curmudgeon extraordinare
Supporter
#5
Detroit says to take the turbo boost sensor and out it into the oil dipstick tube and plug it in. Run it up to like 1500 rpm and measure the pressure. Suppose to be under 5-8 psi.


Something you can do here too.
 

BDKB

New Member
Thread starter #6
I’ll get the oil sampled next
It may be out of my depth to move the sensor over to test the PSI

I was also told that the top side of the vent tube sits over the valve cover has “steel wool?” that prevents oil from coming out of the blow hole?
 
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r3gulator3

Well-Known Member
#7
I’ll get the oil sampled next
It may be out of my depth to move the sensor over to test the PSI

I was also told that the top side of the vent tube sits over the valve cover has “steel wool?” that prevents oil from coming out of the blow hole?
Prevents it when there isn't high blow by.