95 + Owners

[Biggee72]

Not sure if this pertains to owners below 1995 but still a good idea to check it out. There has been a frequently noted issue of Blazers having their oil cooler lines ripped out while driving off road or even through deep snow. These lines also get old and crack with fairly low mileage on them. It's a good idea to have these oil cooler lines inspected every month or two to avoid losing oil and locking up your engine.

[4x4x4doors]

Pre-95 models with the hard lines will start to leak when the gaskets and o-rings get old. The subject o-rings and gaskets are located at the engine block end of the lines on the left side of the engine and accessible from underneath next to the front propeller shaft on 4wd models with the 4.3 engine. These models have hard (steel) lines.
Later models have combination lines with combination hard and soft (hose) lines. A frequent leak point is where the sealed exists where the hard and soft lines meet.

[Black95Blazer]

Thats a good thing to point out about checking on these lines. Mine were so covered in oil and crud i wasnt even sure what they were for at one time. One day i was on my way home and one of the lines decieded it was time to dump all my oil on the road and in my engine capartment luckly I was about 5 blocks away from my mechanic that I trust so i was able to drive my blazer there and have the lines replaced. Now that they are new and clean i keep a eye on them so it does not happen further away from home.

my story about a bad situation
EK

[ex IROC Crew]

In about 2000 or 2001, GM redesigned the engine oil cooler lines on the Blazer. They changed the material of the hard lines from aluminum to steel and changed to a different vendor. With the reduced expansion and contraction of the hard lines and improved crimping, leakage at the joints between hard and flexible lines was eliminated.

In addition, the gasket between the engine and the cooler block fitting was changed from two circular gaskets to one peanut-shaped assembly. With the two circular gaskets, it was possible to over-tighten the retaining bolt enough to deform the block fitting and have leakage, because the fitting was not supported in the center under the bolt. With the single gasket, the material between the rings prevents deformation of the block.