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1992 Saab 900 S Convertible
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Discussion Starter · #1 ·
The best way I can describe this is that my 900 sounds like a diesel on cold starts and quiets down and smooths out after 3-5 minutes.

I'm afraid it could be piston slap? I know it's not lifters because the previous owner had new ones installed.

I've also heard stuff about a Teflon coat used specifically on these 2.1L motors that causes them to be loud.

How can I be sure that this isn't harming my engine? My oil looks fine and there's no smoke coming out the tail pipe.

If needed I can attach a video of the noise.
 

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Sounds that you have low oil pressure in cold start at hydraulic lifters.
Check oil pressure and change oil (and filter).
 

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Also possible that you have a slight exhaust leak somewhere when the pipes are cold. As they heat up they expand, sealing the leak. If it only takes a couple minutes it's probably fairly close to the manifold, or at the manifold itself. Could even be a small crack in the manifold, though this is usually more of a ticking sound.
 

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Discussion Starter · #4 · (Edited)
Sounds that you have low oil pressure in cold start at hydraulic lifters.
Check oil pressure and change oil (and filter).
Here's a clip of the noise
There is a rattling alongside the concerning noise is my broken AC compressor. So please mind that.
 

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Discussion Starter · #5 ·
Also possible that you have a slight exhaust leak somewhere when the pipes are cold. As they heat up they expand, sealing the leak. If it only takes a couple minutes it's probably fairly close to the manifold, or at the manifold itself. Could even be a small crack in the manifold, though this is usually more of a ticking sound.
It sounds more like a diesel engine than a ticking. I attached a link to a video of the noise.
 

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I'm not convinced it's external. Definitely check for exhaust leaks, but TBH, that sounds not far off from my '93 900S when it's cold out. That car has 230k on it, and I just assume there's a bunch of stuff out of spec - probably a slightly stretched timing chain, worn guides/pad, low oil pressure, worn valve train, etc. It's fine after a few minutes, I'm not losing sleep over it.
 

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1992 Saab 900 S Convertible
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Discussion Starter · #8 ·
Sure sounds like exhaust to me. Reach down and feel around the connection from the manifold to the downpipe and see if you can feel an exhaust leak. Do it when the car is cold.
I will do this when I get home.
I'm not convinced it's external. Definitely check for exhaust leaks, but TBH, that sounds not far off from my '93 900S when it's cold out. That car has 230k on it, and I just assume there's a bunch of stuff out of spec - probably a slightly stretched timing chain, worn guides/pad, low oil pressure, worn valve train, etc. It's fine after a few minutes, I'm not losing sleep over it.
It's odd because my 900 only has 62,000 miles. It sat around most of its life, only coming out in the summer and now that I've been dailing it, it has started to get many problems.
 

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Don't think just 'cause a car sat it didn't wear out. Plastics and rubber age just sitting there, cars that aren't run often will accumulate moisture and other contaminants that can impact how fluids (especially oil) works. When they do short trips, or aren't run for very long, fuel can wash cylinder walls of oil which increases wear.

Not saying any of these are affecting you, only don't assume low mileage means "like new." :)
 

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Discussion Starter · #11 ·
Don't think just 'cause a car sat it didn't wear out. Plastics and rubber age just sitting there, cars that aren't run often will accumulate moisture and other contaminants that can impact how fluids (especially oil) works. When they do short trips, or aren't run for very long, fuel can wash cylinder walls of oil which increases wear.

Not saying any of these are affecting you, only don't assume low mileage means "like new." :)
I do have problems with charging and the car bogging down when cold
 

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Discussion Starter · #12 ·
Also possible that you have a slight exhaust leak somewhere when the pipes are cold. As they heat up they expand, sealing the leak. If it only takes a couple minutes it's probably fairly close to the manifold, or at the manifold itself. Could even be a small crack in the manifold, though this is usually more of a ticking sound.
So I felt around the exhaust manifold when it was running and I couldn't feel anything leaking. I did put my head on the valve cover and the noise was very audible.
 

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Discussion Starter · #14 · (Edited)
I didn't change the oil but it was changed in late august. I checked it and it looked okay. I'm planning on changing it soon.

EDIT: I was reading the Bentley manual and it says that lifter noise is a normal part of operation as long as it goes away within 5-30 minutes.
 

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Yep. Assuming you are using a quality oil filter with a durable anti-drainback valve and that you have good oil pressure, it's not unusual for the engine to be loud on startup, especially if the engine has been sitting for several days and/or it's cold out. The 2.1l is definitely louder than the 2.0l as well... My '93 2.1l is quite loud and my '85 2.0l is much quieter. As long as the noise goes away in a few minutes as the oil warms up and circulates it's probably not worth worrying about.

Do make sure you're using a quality oil filter (none of that Jiffy Lube discount crap) and do be sure you're using the correct oil for your situation.... Use a 5w if it's cold where you are, otherwise a 10w is fine.

You might consider removing the valve cover and checking the timing chain condition, guides, and pad and checking oil pressure, but nothing about your video screamed alarm bells to me. IMO it's worth the check - better safe than sorry.
 

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Discussion Starter · #16 ·
Yep. Assuming you are using a quality oil filter with a durable anti-drainback valve and that you have good oil pressure, it's not unusual for the engine to be loud on startup, especially if the engine has been sitting for several days and/or it's cold out. The 2.1l is definitely louder than the 2.0l as well... My '93 2.1l is quite loud and my '85 2.0l is much quieter. As long as the noise goes away in a few minutes as the oil warms up and circulates it's probably not worth worrying about.

Do make sure you're using a quality oil filter (none of that Jiffy Lube discount crap) and do be sure you're using the correct oil for your situation.... Use a 5w if it's cold where you are, otherwise a 10w is fine.

You might consider removing the valve cover and checking the timing chain condition, guides, and pad and checking oil pressure, but nothing about your video screamed alarm bells to me. IMO it's worth the check - better safe than sorry.
Thanks! You have been very helpful. I have some papers from the previous owners when he took it in to get fixed about the same problem and they couldn't find anything wrong when they took the head off the engine and replaced the lifters. I'm going to try to use 5w30 Pennzoil and see if that makes a difference.

Haha then I have to replace my alternator that only works sometimes :)
 

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Discussion Starter · #18 ·
I have to think if it was 'piston slap', wouldn't it come with a report of oil consumption and/or blow-by, with smoky exhaust?
Doesn't seem to be any oil consumption. It's basically still at the Max line from when the oil was changed a few months ago and the coloring of the oil is still amber but maybe a little darker.

There is a plume of exhaust that comes out when I step on the gas from a stop sign but I think that's pretty normal for the most part.
 

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Piston slap doesn't necessarily cause oil consumption. You can have a piston loose in the bore at/near TDC but still have the rings seal well enough to wipe down the cylinder walls during travel. This was a common scenario on tons of small block Chevy motors during the 2000s.... noisy startup, no oil consumption.

The exhaust should never be cloudy, though... certainly not something you should be able to see. What color is the smoke? Have you tried doing a snap test?
 

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Discussion Starter · #20 ·
Piston slap doesn't necessarily cause oil consumption. You can have a piston loose in the bore at/near TDC but still have the rings seal well enough to wipe down the cylinder walls during travel. This was a common scenario on tons of small block Chevy motors during the 2000s.... noisy startup, no oil consumption.

The exhaust should never be cloudy, though... certainly not something you should be able to see. What color is the smoke? Have you tried doing a snap test?
The exhaust is not oil burning color but it is more like a steam color. Honestly it just looks like normal exhaust but there is just a lot of it on cold running conditions. But again I think that might have to do with it being cold and dry outside.

Also I have been looking into exhaust leaks like you described earlier and I think there is a leak in my manifold because when I started it up i pointed a flash light at the manifold and I saw exhaust coming out.
 
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