weird pressure release sound after valve cover gasket replacement!

[K1118]

Hi All, first post so go easy on me.

Recently bought a 96 328i sedan. The car has good paint, body and interior...but, it came with a laundry list of issues. It needs/has:

1- oil leek from the valve cover gasket----Fixed myself.
2- oil leak from the Oil filter housing O rings---Fixed.
3- Front brakes---Will tackle later.
4- rear passenger side door lock doesn't work---Will tackle later...09/05-The PO said the door doesn't work, I just checked it for the first time and it works perfectly:/
5- sun roof tilts but won't roll all the way down---Turns out I have a faulty switch, the sunroof works fine if i press the switch hard enough. 09/05- replaced switch, works perfect!
6- squeaky fan clutch, needs changing---Replaced with brand new genuine fan clutch.
7- driver side power seat does not recline---Will tackle later.
8- OBC has dead pixels, the DIY fix did not work---Will buy a replacement later. I picked up a 7 button obc from a local junkyard for $10. Its just a glorified clock but at least it works; was a direct plug and play too.
9- Front suspension lower control arm bushings need replacement---Replaced with brand new genuine bushings.
10- Oil leak from Vanos oil line---Replaced with brand new genuine Vanos line and washers.

Most of this list is not related to the question I have but i wanted to put everything down here for you all to see and for me to track my progress with this mess I have gotten myself into.

I followed the DIY for the valve cover gasket replacement and everything went well....or so i thought/think. This was my first ever DIY project!

After putting everything back together, I took the car out for a SHORT test drive, it drove fine, the temp was stable, no warning lights etc. But when i pulled into the garage, turned the ignition off and stepped out, i heard a quick pressure release kind of sound. The car never made the sound before so I am worried i might have messed up the repair! The car drives perfect though with a lot of power (well, pretty good for a 2.8 i6).

Anyone have any ideas on what this could be? did I eff up the gasket replacement? or did fixing that lead to some other problem. Also, my AC blows cold but barely keeps me cool. It looks like oil has been dripping on the AC compressor (I think that's what it is) for a while...I dont know if that sound could be related to the AC.... Basically, I have no clue and searching the interwebs yielded nothing.

In answering my question, please remember that i had never ever worked on a car before today, so the more details you can provide, the better. Sorry for the long post!!!!

[flyfishvt]

Long post isn't a problem. Lots of times we only get part of the story and someone leaves out an important detail.

Welcome to the forum. You will quickly become addicted to the handling of these cars.

That vacuum sound could be just about anything but you can eliminate the AC right off by turning it off before you pull into the driveway. Does that sound happen everytime you turn the engine off? If you just start the car for a few seconds and turn it off again?

If that doesn't isolate the issue then the next time you pull in...leave the car running and open the hood. Have someone turn the car off while you try to locate the area the sound is comming from.

That oil you see on the ac compressor could easily be from a leak in the ac system. If its black its probably engine oil. If its anyother color its probably freon or oil from the ac lines leaking out.

[Uberdude328i]

Yanno, I remember my '97 doing that a while ago but I never really paid that much attention to it; it did that when I bought it. It didn't seem to affect anything nagatively so I just got used to it. Had some hoses an seals replaced a while ago and now I can't remember if it's still doing it. When I get a chance I'll check it and let you know what got replaced.

[Mac8008]

my car does that too. I doubt it has anything to do with the V/C gasket. More than likely, you just never noticed it before

[K1118]

Thanks for the response guys.

I did switch off the AC while trying to isolate the sound, it still happened. The oil on the AC compressor is engine oil for sure. Its black and is directly under the valve cover gasket leak. I dont see any coolant leaks but there is some white residue where the coolant pipe attaches to the radiator...maybe an old coolant leak that was fixed by the previous owner?

Will the car make this sound due to a pinched valve cover gasket? The sound seems to be coming from the right side of the block (facing the car). It happens a few seconds after the car has been switched off. It sounds like something is left running after the car is switched off and then turns itself off with the pressure release sound.

Just a thought: Now that the valve cover gasket isn't leaking, maybe the additional oil pressure is straining some other system? Does that even sound plausible?

Uberlude, you are right, the car does not seem to be negatively affected in any way, for now. If you can check your car to see if it still does this and let me know what you replaced, that would be great.

[K1118]

Alright I have decided to ignore the mystery sound for now and move onto the oil filter housing O-ring replacement, new Vanos line, new AC belt and new fan clutch. I have already ordered the parts and will be tackling this job over the weekend. This POS (that i love) car will make a frikkin mechanic out of me! Ahh the joys of being a broke college kid.

I have a couple of questions that I was a little confused about after reading the various oil filter housing gasket DIYs. Firstly, would you guys suggest replacing the gasket as well while I am in there or just the O rings? Second, do i need to take off the housing to replace the O-rings? where exactly on the housing are they located? I have been looking at this picture but the noob that I am, can't figure it out. Can someone please draw an arrow or something:)
http://i295.photobucket.com/albums/mm144/ksaleem1/OFHDiagram.png

Thanks for the help so far guys!

[zebers]

Check your crankcase vent valve. A stuck valve can cause the valve cover gasket to blow out by building up too much crankcase pressure. And vice-versa, and blown-out valve cover gasket could put excessive strain on the CCV Valve, thus failing the valve. The noise could also be a bit of blow-by or exhaust pressure from the rotating assembly coming to a halt with certain valves in certain positions. Just a thought

[JDStrickland]

It's okay. The noise is not pressure release, it is vacuum balance.

The engine draws in air. That's what engines do. At idle, the vacuum is very high. When you shut the engine off, air that was formerly a negative pressure (vacuum) changes to atmospheric pressure, and you hear the change as a whooshing sound.

It is a completely normal sound.


Alright I have decided to ignore the mystery sound for now and move onto the oil filter housing O-ring replacement, new Vanos line, new AC belt and new fan clutch. I have already ordered the parts and will be tackling this job over the weekend. This POS (that i love) car will make a frikkin mechanic out of me! Ahh the joys of being a broke college kid.

I have a couple of questions that I was a little confused about after reading the various oil filter housing gasket DIYs. Firstly, would you guys suggest replacing the gasket as well while I am in there or just the O rings? Second, do i need to take off the housing to replace the O-rings? where exactly on the housing are they located? I have been looking at this picture but the noob that I am, can't figure it out. Can someone please draw an arrow or something:)
http://i295.photobucket.com/albums/mm144/ksaleem1/OFHDiagram.png

Thanks for the help so far guys!
You need Item 6 to cure the leak in the oil canister housing.

You also need to remove Item 11 and the VANOS Oil Supply Line, and smart money would replace all four of Item 10. You do not want to leave the supply line connected and rotate the canister housing out of the way by twisting the supply line around. You should remove Item 11 at both ends and take the supply line off.

The VANOS Oil Line is not called out in the diagram you gave (it is shown, but there is no Item Reference for it), but you are going to want to check that the fittings are crimped tightly to the hose. If EITHER fitting can be rotated, then there is a good chance that there is a leak at that location, and you will want to replace the hose while you are doing the other stuff.

[zebers]

It's okay. The noise is not pressure release, it is vacuum balance.

The engine draws in air. That's what engines do. At idle, the vacuum is very high. When you shut the engine off, air that was formerly a negative pressure (vacuum) changes to atmospheric pressure, and you hear the change as a whooshing sound.

It is a completely normal sound.

What He Said /\

[K1118]

Thanks guys, that makes me feel much better.

JDStrickland, I took the car to a highly regarded autoshop after i bought it (they're BMW specialists). They gave me a complete list of things that my car needs. They specifically listed the "Oil filter housing adapter o-ring" and did not mention the gasket(item 6). In any case, I ordered the gasket anyway and was just wondering whether i should mess with it if it isn't leaking. I also ordered the VANOS line along with 4 washers for both ends. Some write-ups mentioned replacing the Banjo bolt but the guy at Pelican Parts said I don't need to, and that the Banjo bolt almost never needs replacing.

[013137]

It's okay. The noise is not pressure release, it is vacuum balance.

The engine draws in air. That's what engines do. At idle, the vacuum is very high. When you shut the engine off, air that was formerly a negative pressure (vacuum) changes to atmospheric pressure, and you hear the change as a whooshing sound.

It is a completely normal sound.



Truth. My car always does that.

[JDStrickland]

It's difficult to imagine that Item 6 is not leaking. You should not need the banjo bolts, but you will need the four washers -- two for each banjo bolt. You may or may not need the VANOS Oil Supply Line.

My guess is that the shop had a brain-fart and referred to the gasket as an O-ring. There is no O-ring, except those that come with the filter kit.

[Uberdude328i]

Checked it 'cause I said I would. My car is NOT making that noise anymore. Checked the service record from last year and it turns out...nothing that was done could be the part that fixed it. If I'm remembering correctly my mechanic gave all the vacuum hoses and what not a good once over and prob tightened...something. Sorry I can't tell you more.

[K1118]

Thanks Uberdude.

I've decided to move onto the rest of the stuff after some reassuring responses. I was a little overwhelmed by tacking all the major stuff myself (OFH gasket etc.), mostly because I don't have any tools (Read no wrenches, screwdrivers, jackstands:)...I did buy a basic wrench set to get the valve cover gasket done though.

I found an ASE certified mechanic who said he would fix the OFH gasket, VANOS line, the fan clutch, AC belt and the lower control arm bushings for around $180. I think thats a pretty good price compared to the $611 labor i was quoted for the same work by the BMW specialist shop. The best part however is that this guy is a mobile mechanic and will be doing everything in my garage! Couldn't ask for more... Will post updates Monday night.

[K1118]

Alright guys, I had most of the engine problems fixed on Monday (see updated list in OP). The car had been running great with no warning lights ever since.

Today while driving, the check engine light came on. I had the codes read and two came up. p0430 and p0455. I searched and apparently 455 has to do with the fuel cap (I have an after market one that has been working fine for the 250 miles I have put on the car since I got it). The explanation for 430 that autozone printed out for me says:

Definition: catalyst efficiency bank 2
Explanation: Faulty Catalytic converter

Probable causes
1- rich air/fuel mixture
2- High fuel pressure
3- Ignition or fuel injector fault

Are these codes related since they came up at the same time (no CEL before today)? Will getting an oem cap from pelican parts fix both codes?

Here is what I did to the car 30 minutes before the CEL came up. I took out the cabin air filter (broke the new filter while trying to install so currently running without one). My cigarette lighter fuse was blown so i swapped over the one for the sunroof (same amps/volts)..The lighter works now but i noticed that it stays on all the time, even when i shut the car off and remove the keys. I don't see how any of these things can be related to the error messages.

I need to get the car registered and need an inspection done...hoping to not have to replace the Catalytic convertor because I don't have the money for it:(

Finally, the car still drives great. I drove it for about 4 miles since the light came on and have not noticed any difference in the way the car drives. Thanks in advance for any help!

Anyone???? could these two codes be related since they came up at the same time?

[K1118]

** for someone who might run into the same issue**
09/05/2011
The codes turned out to be my mistake. I refueled while the car while it was running. The codes showed up next day though....just tightened the cap, reset the lights and have driven approx 80 miles without any warning lights....

Quick question. My compressor makes a weird sound....I'm guessing because it had oil from the valve cover dripping on it for quite a while. I'm looking to replace my compressor assembly and need to find out which one i have. I didn't see any labels on the underside so i made a video. Sorry about the bad video, I was using my phone and turned the flash on only halfway through. Any help would be appreciated.

http://i295.photobucket.com/albums/mm144/ksaleem1/th_VIDEO0006.jpg (http://s295.photobucket.com/albums/mm144/ksaleem1/?action=view&current=VIDEO0006.mp4)

The fluid droplets you see at the end if my washer fluid, no worries....