2000 Cadillac Eldorado - Odd sound after starting that then settles down

When I start my 2000 Eldorado Cadillac Etc it starts up but it makes a loud noise after starting for a minute what could that be it’s almost like a is hitting a fan or something5

My WAG, valve train noise. Noise diminishes as oil circulates.

where is the noise coming from? inside, outside, front, back, underneath?
what does the noise sound like? ticking, clunking, thud, rattle?
if you can post a clip of the sound it might help. its hard to tell from here.

I’d remove SERP belt and see if noise remains. As a test

Pop the hood & ask a helper to start the engine while you listen to the engine area using a length of old garden hose as a stethoscope to narrow down where the noise is coming from. This sort of problem in cold weather is often related to a pulley or accessory belt.

The noise you hear might be coming from the secondary air injection pump.


This is an electric fan that injects air into the exhaust system to light off the catalytic converter(s) faster.

Why are we still recommending that folks monkey around with pieces of garden hose when you can get a mechanic’s stethoscope on Amazon starting at $8.37?


Had a bad tensioner, sounded like valve clatter to me, so many possibilities. Leave it overnight at a shop and let them figure it out was my cure,

Either way works. Seems more likely a diy’er solving a problem that requires the car tomorrow will have some old garden hose on hand. But if waiting for Amazon to deliver an auto-stethoscope is no problem, that’s a good alternative.

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And just how many people bother to keep old peices of garden hose around ? Not many is what I think .

Those that don’t will have to figure out another method, or wait for the Amazon truck to show up. Ray has recommended using vacuum hose on the show. I don’t get as good of results w/vacuum hose as garden hose. There’s probably a 100 different types & sizes of hose that might work, and an equal number that won’t.

I just threw a lot of old, hardened, leaky garden hose away.
Why would I want to use that stuff in place of a stethoscope?

Hmmm…so you did have some lying around…

Besides, siphoning your neighbor’s gas with a stethoscope just doesn’t work as well.


This sort of topic does nothing but clutter up the thread. If someone doesn’t think garden hose – or whatever a poster said they used as the proper method – the polite, courteous response is to simply post an alternative.

For example: " Rather than garden hose I prefer a mechanic’s stethoscope."

I expect OP’s are smart enough to determine which works best for them, on their own.

I doubt that .

You can buy mechanics ears at Harbor Frieght real cheap . And they don’t require an unexperenced person to turn their eyes away from the turning fans and belts to use them as a piece of garden hose would.

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Since you insist on providing more clutter to this thread, explain

Are you referring to the OP? Why would you insult a poster here like that? It only drives folks with car problems away from the Car Talk web site.

Which is why I also stated…


It’s a matter of emphasis I guess. IMO the polite courteous way to say that same thing is:

“I prefer using a stethoscope to garden hose.”

So, you think that I am discourteous and impolite?

No, I don’t think that at all. But anybody can resolve to be more polite and courteous. Set you standards high, and others will likely do the same.