Help ID-ing new engine rattle 80 SC

[wannaporsche]

Something started rattling yesterday on the underside of my engine that I can't pinpoint… largely because I'm a newbee and the underside is still a mystery. Anyone have an idea what some likely sources would be to start looking at? The engine runs and pulls great, transmission feels smooth, and the gauges (oil/temp/press) all look right on. I'm hoping its a loose mount or heat shield I can tighten up, not a deeper problem. Seems to be coming from the bottom right side around the axel, but I'm really guessing. The sound doesn't change with the RPMs.

1980 Porsche SC mystery rattle - YouTube

[fitchn]

Sounds like chain tensioners to me, but if it doesn't change with engine rpm... I wouldn't drive it until you figure it out.

[porsche930dude]

could be the heat shield on the cat or the heat exhangers rattling. feel around with a good glove on so you dont get burnt and see if you can pinpoint it that way

[Bob Kontak]

Originally Posted by fitchn

Sounds like chain tensioners to me, but if it doesn't change with engine rpm... I wouldn't drive it until you figure it out.

Sounds external to me. Just saying.

[theiceman]

id get under tbere with a dead blow hammer and start "tapping"

[wannaporsche]

Great guys -- thanks for the input.

I went under the car tonight and discovered that it's the right heat exchanger rattling around under there… it's loose on all three headers, and the hose to the cabin is kind of jiggled off too.

I tried to stick the hose back on and tighten everything up as best I could being on my back in the driveway, but I feel like I didn't find all the mounting bolts. I looked thru threads here and the Bentley Manual for details or a diagram, but not much luck. Still wondering if the heat exchangers are something I can tighten up from the driveway, or will I need a lift - meaning my mechanic.