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6.5 Oil Leaks - Running Rotella 5w40 Synthetic

Big T

Big T

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Ever since I started running Rotella 5w40 synthetic in my '99 6.5 I've had leaks. One leak is over near the oil filter adaptor (4wd) and I'm trying to narrow it down to the adaptor or one of the fittings on the stainless oil cooler lines. It's pretty messy over there.

The other leak is straight above the electric 4wd actuator as it is dripping. Could this be the turbo oil return line? If so, how do I correct that?
 
Don't run synthetic in old engines. Leaks are why. Esp on the crimps of oil cooler hoses although you don't have them on. The hoses leaked synthetic even when new...

The o-rings on the oil filter adapters are famous for leaking on any oil. I had one 350 gas leak on 20w-50. You will need new o-rings from the dealer and they are year specific with several designs.

Turbo 4 bolts to the block on the adapter plate and use new RV silicone. You sure the hoses are ok on the drain tube? Loose clamps can do it...
 
WW hit the nail on the head.
Think about an AC system to change from r12 to r134a. If you do not replace all of the hoses the Freon will leak out because the molecules are smaller than the original. The only reason synthetic oil is better than natural oil is because it is engineered with smaller molecules and can lubricate in tight areas better. This is Part of what causes the leaks.

The other factors in the leaks is that the seal material is not designed to withstand the chemicals in the synthetic oil as well as it does the natural oil.
Think about biofuel running in our factory fuel lines they simply cannot handle it you have to replace those rubber lines with a different material designed to withstand the slightly different oil in the biofuel. Because of this factor you can't always completely stop the leak by changing back to conventional oil, you can however slow it down.

If possible bring the adapter orings in with you, second trips suck!
 
I just did an oil change with the synthetic.

So I need to pull the adaptor and bring it into the dealer to match up o-rings?

Turbo 4 bolts to the block? Need to be clearer. The oil return line for the turbo has 2 bolts where it mounts at the turbo. What about where it enters the engine?
 
Found the oil leak. It was coming from the fitting of the rear oil cooler line above the oil filter:

attachment.php


I thoroughly wiped it clean and observed it leak with the engine running. The fitting had slightly worked itself loose. I was able to grab and tighten it without removing the oil filter adaptor.

I have another leak and I posted that on the 6.5 engine board.
 
I replaced that short hose as it was so dry and hard it couldn't be tightened enough.
bison said:
The tube exterminates in a short piece of hose,..most likely were the leak is cause of loose hose clamps,A screwdriver is your freind there.
Click to expand...
 
I saw that connecting hose and the 2 clamps. I grabbed the clamps to see if they were loose and they would not budge. The plate with 4 bolts onto the block was dry.

The fluid looked like it was coming from the spot with the drip in the photo. It could be coming from some place higher. I'll get a pressure tester and go through it without the engine running.
 
I saw that connecting hose and the 2 clamps. I grabbed the clamps to see if they were loose and they would not budge. The plate with 4 bolts onto the block was dry.

The fluid looked like it was coming from the spot with the drip in the photo. It could be coming from some place higher. I'll get a pressure tester and go through it without the engine running.
 
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