Exhaust system and Oil pressure light problems

I have two problems with my 2001 Pontiac Grand Am SE 4 Cyl FWD with 210,000 miles.

The first one is the exhaust system. Whenever I am driving and pressing the accelerator, the car makes a loud roaring or revving sound. Not much noise when in park and idling. Is this normal? I suspect the problem may be the muffler. This is a 23 year old car with over 200,000 miles and I don’t think the muffler was ever replaced. Anything else that makes this loud noise?

I also keep getting an annoying P0440 code that just won’t go away. I have had this code for many years now and it just keeps coming back after getting car mechanic to fix it, not sure why. I think the code has to do with things like gas cap, charcoal canister, purge valve and vent valve. I went to my mechanic in August of last year and they changed the purge solenoid after doing diagnostics test. They cleared the code and it was gone for several months and now it is back again. Did the purge solenoid fail again or is it something different this time? Can I go back and have them replace it under warranty since they do 12month/12,000 miles warranty.

I also got them to fix another related p0440 code many years ago and it was gone for a while before coming back again. Maybe I need another mechanic to fix this problem? Or should I take it to a muffler shop and have them check my exhaust system?

The second problem is my oil pressure light. I usually change my oil every 3,000 miles when the change oil light comes on. But for some reason, when I am near the time to change it, like around 2,000 miles, the oil pressure light will quickly come on and off whenever I go over bumps or do sharp turns. I check the oil level and it is at max line so I don’t think there is any oil leaking.

After I change the oil, this problem goes away and doesn’t happen anymore. It comes back again when I am near the oil change miles. So around 2,000 something miles, the light will start quickly come on and off whenever I go over bumps or do turns. Is it because my oil level is kind of dirty so the oil level sensor not detecting the oil? Or all the oil goes to one side on the oil pan? How do I fix this problem? It is kind of annoying to hear a warning sound when I go over bumps or do turns.

The engine makes the noise, and a failure of some component along the exhaust system can make exhaust gasses (and noises) escape. A good local exhaust shop can probably diagnose this quickly and fix it.

The oil pressure sending sensor may be going bad, or the wire to it is loose. Either way it’s usually a simple fix.

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If I’m not mistaken, I believe this is the same car that has traction issues, and likely needs a new set of tires.

I think you also need a new muffler, and possibly other exhaust-related parts. A muffler shop can diagnose this.

And the low oil pressure light and your oil change frequency are not directly related. Admittedly some cars do have an oil change indicator light…but I don’t think a 2001 Pontiac did. If you’re seeing this low oil pressure light come on regularly…that tells me either you have an oil pressure problem, or the oil pressure sensor is going bad. If the oil is getting low, then you either have an oil leak or the engine is burning it. Either way, low oil pressure is a quick way to destroy an engine.

Having said all of that…with all these known and potential issues on a 20+ year old car with 200K miles… personally, I’d be evaluating whether or not I wanted to just get a new(er) car. The problems on this car are only going to grow. But that’s a financial decision only you can make.

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The only noisy part of the car connected to the accelerator is the engine. The engine exhausts that noise through the muffler so, Yes, you should have the entire exhaust system checked for leaks.

A P0440 is a code that you can get if you don’t tighten the gas cap properly. Turn it until it clicks. That is the very first thing to do when that light comes on. Based on your post, I’d say you aren’t getting it tight enough all the time.

3000 miles seems more than often enough to keep the engine clean… How much TIME elapses between changes? If you are changing once every 18 months, I’d guess the engine is sludged up and the oil pickup is somewhat clogged cause an oil pressure drop. Or the engine is just so worn the oil has broken down by 2000 miles and the engine won’t maintain pressure anymore. If you use 5W30 or 10W30 oil, I’d suggest 10W40 oil.

You don’t have an oil LEVEL sensor, you have an oil PRESSURE sensor as you correctly stated earlier. When you see that red light, it is because the pressure is low, not the level.

And are you sure the oil level at the dipstick is correct? Do you add oil between changes? How much?

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Actually, I believe the Grand Am has both. Mine did. It has a level sensor and they become sketchy if they get any build up on them. I was able to clean mine and restore it to normal working order…it had 270k miles on it :wink:


The exhaust noise might be caused by a leaking exhaust flex joint.

This allows the flexing of the exhaust system as the engine moves from the torque applied when the vehicle is in gear and the throttle is applied.

The oil light might be a bad oil pressure switch or a worn engine with that many miles.

Bring it to a shop so the exhaust system can be inspected for leaks and the oil pressure tested with a mechanical oil gauge.


The Change Oil light usually comes on at around 3,000 miles so I just follow what the car computer says and I usually change my oil every 3,000 miles, give or take several hundred miles. This Oil Pressure light problem usually happens when I reach the miles near my normal oil change time. So around 2,000 something miles, the light will quickly come on and off whenever I go over bumps or take sharp turns. It doesn’t stay on at all, it just quickly comes on and off. If I am just driving on normal flat straight roads, nothing happens. It also makes an annoying loud warning sound. The problem will go away completely after I do an oil change but it will come back again after certain miles. So that’s why I was thinking maybe the oil sensor not detecting oil because oil got too dirty. So whenever I go over bumps or do sharp turns, all the oil goes to one side on the oil pan or something.

I change my oil at least once a year. Sometimes I don’t do a lot of driving and sometimes I do a lot of long distance driving. So when exactly I change oil depends on how much I drive the car, I don’t have an exact time interval. My last two oil changes were in June 2023 and January 2024. Right now I am at 2,200 miles. I believe I use 5W30 but the car mechanic invoice paper sometimes says 5W20. I asked them about it and they said it’s ok to use 5W20. I have no way to verify the oil level other than looking at the max line on the dipstick. I don’t add oil between changes.

Every time after I add gas, I turn the gas cap until it clicks and just to make sure, I turn it a bit more so I hear a few more clicks. I also replaced the gas cap but same code problem so I don’t think it is the gas cap.

Don’t use that grade.

That IS the proper way to check oil… and if the level is below the MAX line, it is less than max. There is a MIN line, look harder. If it is at the min line add 1/2 quart and recheck. Add the rest of the quart if it is still low.

I strongly suspect you SHOULD add between changes and I think that is the reason for oil light. I can not believe a 210K mile 4 cylinder does’t use at least a quart of oil in 3000 miles.

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You should probably have a shop read your actual oil pressure to see how good or bad it is.

If your car is spec’d for 30w then 20w will result in lower oil pressure since it is thinner. A mechanical oil pump is pushing xx weight oil thru xx bearing clearances. Lighter oil means lower oil pressure. You don’t have “new” bearings. You have old, worn bearings with more clearance.

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Suggest to ask your shop to put the car on their lift, then put it in gear & rev the engine as a tech listens along the length of the exhaust system using a rubber hose as a sound-isolating stethoscope. They may discover there’s actually no problem, what you are hearing is what the manufacturer wanted the new car buyer to hear.

For the p0440 problem, suggest to use the internet to study how you particular car’s (& specific configuration) evap system works. The code means the computer has found a leak in the evap system. But it has no diea what the cause is. It is sort of like if your swimming pool has a leak. You know there’s a leak b/c the level keeps going down, but you have no idea what is leaking? A pipe? A valve? A crack in the side of the pool? Maybe it is just the water is evaporating quickly b/c the weather is hot and dry, who knows?

I can’t speak to your particular car, but in general the gasoline vapors in the gas tank are not allowed to be released into the atmosphere b/c any released gas vapors causes polluted air. So keeping them inside the car, the basic objective of the evap system design. The problem is that when you fill your tank, that pushes the vapors out of the gas tank, so they have to go somewhere. They temporarily go into the evap canister. You can probably see that part if you look around, shaped like a can you buy 3 tennis balls in, may be in the engine compartment, may be back by the gas tank. The next problem, that canister cannot store much more than one fuel tank refill’s worth of fumes. So the fumes in the canister have to be moved into the engine and burned away when the engine is running. The next problem is it is impossible for the fumes in the canister to move to the engine unless air first comes into the system to replace them. To accomplish all these there’s two valves, one to allow air into the system (the vent valve) and one to allow the fumes to pass from the canister to the engine (the purge valve). As you might e4xpect there’s a bevy of hoses between the tank and the valves and the engine. There’s often other valves and gadgets involved with this quit complicated system. The next problem is what with all the complications, the valves and hoses, even the fuel tank, can develop leaks and thwart the objective of keeping the fumes contained. The car’s computer therefore must test that the system remains air-tight. To do this it closes both the vent and purge valve measures the resulting pressure. How it does that varies car to car. On some the car’s engine pulls the fumes and creates a vacuum (negative pressure). On others the car has a separate air pump that pumps up the pressure. On even others, the car has a separate vacuum pump that creates a vacuum that way. So all in all there’s a lot of reasons for a P0440. There might not even be a leak, could be the sensor that measures the pressure is faulty.

One way to address the p0440 is to keep replacing parts on a guess until it goes away. As you’ve discovered, this process can go on an on. Very easy to run out of money before running out of guesses. The better alternative is a smoke test, where the shop uses a special machine that blows visible smoke into the system, then they look for where the smoke is emerging. They either see smoke coming from a leak, or they don’t . If they do, they know where the leak is located. If they don’t, the problem must be something associated w/the pressure sensor.

For the flickering oil-pressure warning light, ask you shop to measure the oil pressure using their calibrated shop gauge.

The V6 has an oil level sensor, the 4 cyl. (which the OP has) does not.

If they said it’s ok to use 5W-20, it’s because that didn’t have 5W-30 in stock or thought you wouldn’t check your owner’s manual. 5W-30 is the only weight recommended for your engine so use it. A 20 weight could cause the oil pressure light to flicker.

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Mine was an earlier year but had the Quad 4 and it definitely had the level sensor.

I found one example that appeared to fit but it may be trim related. But it wasn’t clear enough to say for sure so I trust you know this version of the 4cyl did not come with it.

Concur, it is not a good idea to substitute 5W-20 for a recommended 5W-30. That’s b/c the higher number applies when the engine is at normal temperature. Which always will happen on longer drives, irrespective of the ambient temps. In a pinch it might be ok to sub 10W-30 for 5W-30 in the summer. B/c the lower number applies when the engine is at ambient temperature when first starting in the morning . It is warmer in the summer so 10W would probably be ok after first staring the engine then. Best to only use the spec’s recommended by the manufacturer of course. I’ve always used 10W-30 in all of my cars over the years, per manufacturer’s recommendation. I used a CC oil spec for my VW Rabbit though.

5-30 was replaced by 5-20 and then they snuck in x-16 oil and I just read about x-08 oil. Story had snip from owners manual that said if x-08 was not available you could substitute x-16 till next oil change. 8w oil? For a 0.8% increase in fuel economy?

You forgot to add emoticon::crazy_face:

The Japanese Automotive Standards Organization (JASO) plays a crucial role in setting automotive standards within Japan, a process that significantly influences the quality, safety, and performance of vehicles and automotive components. JASO is responsible for establishing a range of standards that cover various aspects of vehicle manufacturing and maintenance. These include engine oil specifications, such as the viscosity and performance requirements crucial for engine lubrication and protection, as well as standards for other vehicle components like electrical systems, transmissions, and braking systems. By defining these standards, JASO ensures that automotive products and vehicles in the Japanese market meet consistent and high-quality performance criteria, contributing to the reliability and safety of the automotive industry in Japan.

JASO is part of the Society of Automotive Engineers of Japan, similarly to the Society of Automotive Engineers (SAE) in the United States


Customer: my oil light flickers with 20w oil?
Shop: we can replace ur oil pressure switch.
Customer: my car needs 30w.
Shop: ur motor is worn out,

I added 2 quarts of 0W-16 to my 2000 Dodge between oil changes, I am not concerned about the “best viscosity oil” for the engine, and I often shift at 5000 rpms.

There are complaints on the Club Lexus forum about Lexus dealers using 0W-20 bulk oil in late model cars instead of 0W-16, like that will make any difference.

Those customers could insist that the dealers use 0W16 grade but they would likely have to pay more for the oil part of the change.

The local Lexus dealership prints “0w-16” on their maintenance invoices, but–of course–they could be lying.