help with funny startup noise, common on Fords

[1 FMF]

on a late 90's E250 van, 90k miles, triton v-8, it just started having a funny noise on cold startup. I say common with fords because my dad's earlier 90's lincoln does it all the time on cold startup, that thing has 100k or 200k miles on it. It's not rocker arm clatter, nor is it any type of knock. It's a tinny sound, higher pitched, fairly loud, and obvious. It only lasts for 1-2 seconds immediately on startup. It almost seems like it isn't coming from the engine, more from the transmission area, exhaust, or rear of the engine. You can barely hear it if you are in front of the engine with the hood up, you really hear it if your inside the vehicle or off to the side. If I had to guess what would be capable of making the sound I'd guess an idler pulley. It's definitely not belt squeel. The van is very well maintained. I'm failry certain it isn't oil related within the engine. I will try to get an audio clip, until then any suggestions?

 

[1 FMF]

just thought of another way to describe it. It sounds like massive pinging on startup. And like someone's inside the exhaust or catalytic converter tapping very fast with multiple hammers, like hammers banging on a thin sheet of tin.

 

[tom slick]

my F-150 makes a long click/short squeal when cold for about 1-2 secs. I was told it's the a/c compressor's clutch. does it do it with the A/C or defogger on? what about off?

 

[Propflux01]

I have a friend whos 201 F-150 'jingles' like that on startup. For him, it comes from the exhaust hanger area.

 

[hone eagle]

heat shields are possible,when they corrode off their hangers they may rattle or ping