I've gotta disagree with Sean on this one...
Oven Cleaner is a Super "Base" (Opposite of Acid) Cleaner...

I will not recommend it's use when the possibility of "NON-COMPLETE" removal
exists.

"I ain't gonna trust my intake tract/engine to my ability to "Rinse" a BASE out
with a Carwash."

If you've got the Intake Off...
Take it to a Radiator shop and have it "Hot Tanked",problem solved.(Maybe $20.00 USD)

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'84 300SD sold
124.128