My heat still smells like Gunk since the last time I cleaned my engine two years ago. Would it be feasible to remove the ducts and then run water through the heater portion of the heat exchanger to remove the smell?

Squirt a couple/few of shots of Ozium (WalMart, FLAPS) into the intake of the blower, careful, pretty potent air freshener!!

Maybe you could take them to a machine shop and have them boiled out.

Rinse them well, install and run to dry.

KT

If I take them off then I'd just replace with stainless.

Since everything is running great, I kind of didn't want to have to take the HEs off for fear of a breaking an exhaust stud or something not to mention that it looks like a big job.

I was looking at an extra set of HEs that I have and it seems like I should be able to remove both hoses from the HEs and then flush water through them.

I have done exactly that. I pulled the tubes. sprayed foaming engine cleaner in, them hit them with a power washer inside. Only time I have ever had heat in a 914 that didn't stink (until of course my bad oil leak coated everything all over again )

If you use water to flush them in place, hook up a hose to the HOT water from your washing machine faucet and use some of that orange cleaner to break it down.

KT