6.5 mysterious oil leak
 

Hello all, I am new to this site.
Well, I recently purchased a 1998 3/4 ton GMC Sierra with the 6.5 Detroit. I noticed a few little oil spots on my driveway so I went under there to check things out, and on the driver's side, oil was on the oil pan, and all in the area. The area around the oil filter was also covered in oil. I then wiped everything off to make it dry, and a little tight area around the oil filter began to very snowly leak. Has anyone else ever run into this problem? and If so, what could the problem be and how much money would you say it would cost to fix? My immediate suspicion is the valve cover although input would be nice.

Oil cooler lines more than likely and you will want to fix this as soon as possible or they will fail and you will be looking for an engine.

Ok I did some research about oil cooler lines and some have said that the factory ones aren't that great and aren't known to last very long, do you know if there are aftermarket ones available that are more reliable than the factory ones?

There are multiple aftermarket sellers for new lines, they are steel braided and come with the adapters to the block and a new oil cooler,
This is where I got mine.

GM 6.5TD/6.6L Diesel: Espar Heater Parts, EZ Oil Drain Valves & More Industrial Products by the Lubrication Specialist

Put new oil filter adapter seals as well while you got it off.


You have to get the big O ring from the dealer.


The kits sold by all the parts chains is the same and doesn't include the right big O ring.

I just went through this, Just go to the dealer and for around $40 you can get all the right stuff and have 4 spare sets minus the copper O ring.