so i just replaced my upper oil cooler line with a new one from autozone, and after a couple of weeks, the vibration of the engine rubbed a hole in it by knocking it into that lip on the firewall... my engine shackes from side to side quite a bit (old stretched engine mounts?????)

are there any tips on replacing the lines with something else? or some better brand? can I go all rubber for instance somehow? i dont like the flimsy aluminum ends out oil lines have...

I am running rubber lines from the block all the way to the cooler. The bulk hose you can get at any autoparts store can hold up to 250psi safely which is plenty for the engine oil. I haven't had any problems and have been keeping my eye on it for the last 3k miles or so.

The exhaust manifold would probably cook that rubber inside of a year, I would think?

I had replaced mine with the factory lines and made sure to put new clips in the fittings on the block.

The lines are still soft and plyable after a few k miles. Like I said, I'm keeping my eye on it. Everytime I check the oil I check those lines. If they ever do start getting cooked I'll replace them and put on some type of head sheild.

I suggest you first replace the engine mounts. I have a set of new GM EOC for an 86 if you're interested in getting good & proper parts.

how would i know when the engine mounts need to be replaced?
is there any metal braded line alternative maybe? how would I go about the fittings?

Do a power brake forward & reverse & observe if the engine moves excessivley.Also note if the end of travel has a bump stop.Take a close look at the rubber inserts. They collapse, split & allow engine movement, particularily when jumping on the throttle on take off. I can also feel viberation at idle & low speeds when they are damaged. The viberation also caused buzzing on my 6.2 trucks. BUY genuine GM mounts only, as the durometer rating is correct rubber to prevent the numerous side efects. Aftemarket mount had short life as the rubber had short life. You might check the next generation mounts for fit as they go forever.Look similar in apperance as I recall. On the oil cooler lines the bore of any replacement fittings needs to be at least as large as OEM. I don't think any can fit as well as the OEM & they last over a 100.000 miles. You might have a hose shop install an up grade silicone hose to the GM fittings to maintain hose fit & integrity. These are all service wear items that require periodic replacement,not a fault of GM. JMO

Yeah, do check out the engine mounts and also investigate if maybe the idle is set too low. Sounds like your engine may move around too much. These do often shake a little at idle but it sounds like maybe yours is a little much.

As far as the lines go, talk to somebody at a local hydraulic shop. Sometimes they can make something for you. I never did find a shop that would make a replacement for the aluminum line that runs behind the radiator as it has a very special fitting on the end but I bet somebody would make a replacement for that rubber line.

great ideas guys, thanx!
I dont think the rubbers inside the motor mounts are completely destroyed, just prolly old and stretched out... very interesting to hear about the idle - YES, it does feel like it idles too low, sometimes I just keep my foot on the pedal a bit at a stop... which brings me to a few questions:

how do I change the idle? i should know this, but i dont...
also, how would one go about installing a tachometer on a diesel?

and as far as the lines, so far i hammered some on that firewall lip and rounded it all up... I am also thinking about wrapping something around the aluminum part of the oil line to protect the fragile aluminum - there was literally a 1/4" hole there within like 300 miles or so from a brand new install... and I remember the PO saying something about changing those lines right before I got the truck, so seems like an issue with this particular vehicle for sure... any ideas on what i can use?

theres just a idle screw like on any old carb, its a flat head on the drivers side of the injection pump sorta under the intake you know? turn it cockwise to raise the idle, and u will need a fairly long screw driver to reach it