Does anybody know a procedure for doing ICP on polyglycol gear oil (1000 cSt)
The oil I'm refering to is Kluber Syntheso HT 1000

We have typically used Xylene to dissolve the polyglycol oils. Warning though, the polyglycol will fall out of the Xylene solution after about 5 minutes, so prepare the samples as they are about to be analysed.

I WOULD LIKE TO KNOW IF THERE IS A DIFFERENCE BETWEEN DIESEL FUEL AND HOME HEATING OIL

Thank you BJ, yes I have found out in the meantime that:
Mobil: Dilute with Xylene 4:1
Shell: Dilute with Toluylene 2:1 and makeup the rest with A-1 jet fuel shake well just before test.
We tried the Mobil method at 10:1 and works OK and you're right we have to shake well just before test.

Also i have found that using TAN solvent works well ie 1:1 toluene and propanol. Hexane can also be subbed in for propanol.

we use white oil to dissolve the lubricant oil and use Co as the internal standard,dilution rate is 1:20.

If you have the ability to run water-based ICP samples, you could try a straight water dilution. The PAG will typically mix with it much easier and be somewhat more stable than a PAG and an oil-based diluent. Isopropanol and water is another possibility.