I have a 1986 chevy 4x4 with the 6.2L diesel c series engine. I plan on completely restoring this truck in the near future. The truck has about a 177,000 miles on it. It starts hard, leaks oil and doesn't have a lot of power anymore. Has anyone had good results in rebuilding the 6.2L? I have talked to several machine shops and they don't recommend rebuilding them but would not really give a reason why. I would really appreciate anybody comments or suggestions on this matter Thanks!
Jeremy

The 6.2 is a good, solid, long lasting platform. I have rebuilt many of them over the years. I have all machine work done professionally by a local competent machine shop. I do all assembly work, hand fitting all parts. I use quality aftermarket parts, not the cheapie "machine shop wholesale" stuff. Brand name on everything. FelPro, Federal Mogul, ARP, etc. The brands vary, the idea is quality. The trick is finding a good (no cracks) block and "doing it right".

177K miles is low mileage for a 1986 6.2L engine. Oil leaks usually come from failure of the rear main rope seal. The rope seal can be replaced with a 2 piece neoprene type seal (Fel-Pro would be my choice). That rope seal doesn't last forever.

I would check out your engine to see what is wrong. Do you have good fuel pressure, clean fuel filter, pump timing okay, clean air filter, EGR working, etc.? I have about 225K on my 1984 6.2 and it is in excellent condition. Changing oil/filter about every 3K miles and keeping a clean fuel filter is very important.

That EGR is not helping your engine. The first thing I did on my C engine was to remove the EGR and the butterfly in the left exhaust manifold and install solid intake manifold gaskets.