318ti.org forum

Go Back   318ti.org forum > Technical, Maintenance and Modifications > Maintenance

Notices

Maintenance Service Interval questions, oil change info.

.
» Recent Threads
1999 M-Sport For Sale
12-31-2023 05:10 PM
Last post by Coop540iT
03-23-2024 06:39 PM
1 Replies, 96,092 Views
Once again 318ti owner...
03-20-2024 12:39 PM
Last post by two30grain
03-22-2024 02:04 PM
1 Replies, 59,103 Views
What brakes do I...
03-20-2024 03:27 PM
Last post by huirtera
03-20-2024 03:27 PM
0 Replies, 56,445 Views
M50+manual swap bastard...
03-01-2024 11:00 PM
Last post by Andy318
03-18-2024 02:34 PM
3 Replies, 131,419 Views
Reply Share/Bookmark
 
Thread Tools Display Modes
Old 05-03-2011, 09:27 PM   #1
bimmern00b
Senior Member
 
bimmern00b's Avatar
 
Join Date: Oct 2007
Location: Virginia
Posts: 242
iTrader: (0)
Default Mystery Noise

As I was going to pick up last minute items to replace my hub, this noise started up:

I put my code scanner on but it says that everything is fine, I can drive the car but choose not to until I can resolve this. It also makes the car idle a bit rougher than normal. Does anyone know where this sound is coming from and what it is I need to do to correct it? Driving my brother's Aztec is killing me on gas!!! Thanks

Last edited by 1996 328ti; 05-03-2011 at 09:43 PM.
bimmern00b is offline   Reply With Quote
Old 05-04-2011, 01:30 AM   #2
trikzta
Senior Member
 
trikzta's Avatar
 
Join Date: Jun 2009
Location: Miami, FL
Posts: 874
Vehicles
iTrader: (2)
Default

im not sayin it is this but the only time i heard something similar was a alternator going bad
trikzta is offline   Reply With Quote
Old 05-04-2011, 01:33 AM   #3
familytruckster
Senior Member
 
Join Date: Jul 2009
Location: MD/PA/DC
Posts: 1,629
Vehicles
iTrader: (3)
Default

probably a bearing someplace- you need to pinpoint it. Could be alt, idler pulley, or even just a vacuum leak.
__________________
No more ti.
familytruckster is offline   Reply With Quote
Old 05-04-2011, 01:50 AM   #4
xxxJohnBoyxxx
Senior Member
 
Join Date: Dec 2007
Location: Gulfport, Florida
Posts: 3,208
iTrader: (1)
Default

Idler pulley
xxxJohnBoyxxx is offline   Reply With Quote
Old 05-04-2011, 02:16 AM   #5
cooljess76
NOBODY F's with the Jesus
 
cooljess76's Avatar
 
Join Date: Oct 2006
Location: Ventura California
Posts: 7,824
iTrader: (6)
Default

When was the last time the water pump was replaced? Might wanna try wiggling the water pump pulley to see if there's any play.
cooljess76 is offline   Reply With Quote
Old 05-04-2011, 02:17 AM   #6
bimmern00b
Senior Member
 
bimmern00b's Avatar
 
Join Date: Oct 2007
Location: Virginia
Posts: 242
iTrader: (0)
Default

Well now here's the thing. When the engine is cold it sounds fine and doesn't make itself known until I drive down the road a bit and when I turn the car off it sounds like something is depressurizing, sort of like a woosh of air or something. I tried to look and see if it was any of the vacuum hoses but they look fine on the front of the engine but I will have to take the intakes off to check the hoses that run under them. Is there a way to test if it's the idler pulley? Well I imagine take the belt off and check it, which would be a good time to change the belts anyway...

Last edited by bimmern00b; 05-04-2011 at 02:34 AM.
bimmern00b is offline   Reply With Quote
Old 05-04-2011, 02:33 AM   #7
bimmern00b
Senior Member
 
bimmern00b's Avatar
 
Join Date: Oct 2007
Location: Virginia
Posts: 242
iTrader: (0)
Default

Quote:
Originally Posted by cooljess76 View Post
When was the last time the water pump was replaced? Might wanna try wiggling the water pump pulley to see if there's any play.
Haven't done anything with the water pump at all in the almost four years that I have had it. I will check the idler and water pump tomorrow since as I said will finally give me a reason to change those belts. Thanks for the input guys, I appreciate it. I gotta keep the Obsidian ti on the road!
bimmern00b is offline   Reply With Quote
Old 05-04-2011, 03:26 AM   #8
cooljess76
NOBODY F's with the Jesus
 
cooljess76's Avatar
 
Join Date: Oct 2006
Location: Ventura California
Posts: 7,824
iTrader: (6)
Default

Quote:
Originally Posted by bimmern00b View Post
Well now here's the thing. When the engine is cold it sounds fine and doesn't make itself known until I drive down the road a bit and when I turn the car off it sounds like something is depressurizing, sort of like a woosh of air or something...
Can you isolate the noise to the back, front or either side of the engine? Does it fluctuate with engine rpm? Now that you mentioned the "depressurizing/wooshing sound", I'm thinking you might have a bad CCV (crank case vent valve) or a bad secondary air pump check valve orrrrrr a leaking secondary air pump. Here's how you could check each one of those things:

CCV VALVE - It's a black disc shaped plastic piece located towards the back of the engine up high, just to the left of the upper intake manifold. It should have a little slit on the bottom of it. With the engine running, place your finger over the slit on the bottom of the CCV valve, if you hear the whistle note change, your CCV is clogged. Unfortunately these things get brittle over time, so if you try to take it apart and clean it, it'll likely crumble in your hands. The part costs between 50-60 bucks new.

SECONDARY AIR PUMP - This is a black pancake shaped plastic valve located just aft of the airbox. There's two hoses going to it. One goes to the airbox, the other is a rigid plastic line that goes across the front of the engine compartment to the secondary air check valve. The secondary air pump is composed of a stack of disc-shaped plates that are held together with 6 aluminum rivets. Over time, these rivets break and allow the plates to separate which in turn allows the pump to leak. The pump ONLY RUNS FOR THE FIRST 30 SECONDS after a cold startup. So to check it, wait until morning or after the car has been sitting for several hours. Pop the hood and be ready to run around and stick your hand near the secondary air pump IMMEDIATELY after starting the engine. You should hear the pump running. If you feel air blowing on your hand, your pump is probably leaking. You can easily fix it by removing the pump assembly and replacing the broken rivets with nuts/bolts.

SECONDARY AIR PUMP CHECK VALVE - this is a black disc-shaped plastic piece located on the front passenger's side of the engine compartment just aft of the radiator fan. It'll have a rigid plastic hose going from it across the engine compartment to the secondary air pump. This valve should only allow air to travel in one direction, from the secondary air pump into the exhaust stream. With the engine warm, but not running, squeeze the two tabs on one end of the plastic hose and pull it off either the check valve or the secondary air pump. If you disconnect it @ the valve, make sure the hose is secured so it won't get tangled in the belts or fan. If you disconnect it @ the pump, take the same precaution as to not let it get tangled in the belts or fan. Start the engine, then feel if air is being pushed back through the plastic hose or the check valve itself. You shouldn't feel any air at all and if you do it may be hot so be careful. If you do feel air, your check valve is bad.

INTAKE BOOT - You should also check your intake boot for cracks, they're known to split at the seams and it's usually invisible to the naked eye. The best way to check it is to buy a can of brake/parts cleaner(NOT CARB CLEANER). With the engine running, spray a sh!tload of brake cleaner on the intake boot. Try to get it up underneath the boot as well. This is the ribbed rubber boot, just aft of the MAF sensor and airbox. While you're spraying brake cleaner on the boot, listen to the engine rpm's. If you hear it fluctuate, usually it'll rev up really high, then you need to replace your intake boot asap. You can temporarily fix it with duct tape. Just wrap the heck out of it to create an airtight seal. Note; you should also spray brake cleaner on any vacuum hoses as well as around the upper and lower intake manifold especially where they connect and mount to the cylinder head. Same thing, if the rpms rev up, you know you have a leak.

WATER PUMP BEARING - Grab the water pump pulley and try to wiggle it. you shouldn't have ANY play whatsoever.

Hope this helps, best of luck!

Last edited by cooljess76; 05-04-2011 at 03:30 AM.
cooljess76 is offline   Reply With Quote
Old 05-04-2011, 03:36 AM   #9
zoner
Senior Member
 
zoner's Avatar
 
Join Date: Oct 2008
Location: Los Angeles, CA
Posts: 1,464
iTrader: (7)
Default

Does the sound stay constant with fluctuation in RPM's, or does it get higher pitched or louder as RPM's increase?
zoner is offline   Reply With Quote
Old 05-04-2011, 03:50 AM   #10
bimmern00b
Senior Member
 
bimmern00b's Avatar
 
Join Date: Oct 2007
Location: Virginia
Posts: 242
iTrader: (0)
Default

IIRC, the sound is constant but at speed it's hard to tell since the engine and road noise drowns it out, but once I start slowing down it still sounds constant.
bimmern00b is offline   Reply With Quote
Old 05-04-2011, 03:57 AM   #11
bimmern00b
Senior Member
 
bimmern00b's Avatar
 
Join Date: Oct 2007
Location: Virginia
Posts: 242
iTrader: (0)
Default

Quote:
Originally Posted by cooljess76 View Post
Can you isolate the noise to the back,

(snipped)


WATER PUMP BEARING - Grab the water pump pulley and try to wiggle it. you shouldn't have ANY play whatsoever.

Hope this helps, best of luck!
Thanks, I will print this out and check them tomorrow. I just replaced that rigid plastic hose a while back, I am more than a little familiar with it. As for the air pump, I am definitely going to have to try to fix it because it looks like the PO tried to superglue it shut and a number of the rivets seem to be either broken or close to it. Any idea to what size and length screws to use?

Oh, I almost forgot, the sound is loudest at the front.

Last edited by bimmern00b; 05-04-2011 at 04:29 AM.
bimmern00b is offline   Reply With Quote
Old 05-04-2011, 05:52 PM   #12
trikzta
Senior Member
 
trikzta's Avatar
 
Join Date: Jun 2009
Location: Miami, FL
Posts: 874
Vehicles
iTrader: (2)
Default

if the noise doesnt stop after 5mins of running the car after a cold start you can rule the secondary pump out.. since it only runs 30secs after a cold start.. yeah mine did somewhat a noise like that but it only lasted like 20seconds once a day or twice a day.. after that never.. i did what jess said with nuts/bolts and well is much much quieter now but can still hear it for the same amount of time
trikzta is offline   Reply With Quote
Old 05-04-2011, 08:35 PM   #13
bimmern00b
Senior Member
 
bimmern00b's Avatar
 
Join Date: Oct 2007
Location: Virginia
Posts: 242
iTrader: (0)
Default

Quote:
Originally Posted by trikzta View Post
if the noise doesnt stop after 5mins of running the car after a cold start you can rule the secondary pump out.. since it only runs 30secs after a cold start.. yeah mine did somewhat a noise like that but it only lasted like 20seconds once a day or twice a day.. after that never.. i did what jess said with nuts/bolts and well is much much quieter now but can still hear it for the same amount of time
Yeah I ruled out the pump since it was only after the car has been running for a while. When the engine is cold I don't hear the noise at all, but after I drive it approximately 2 miles it starts up.
bimmern00b is offline   Reply With Quote
Old 05-06-2011, 05:16 PM   #14
bimmern00b
Senior Member
 
bimmern00b's Avatar
 
Join Date: Oct 2007
Location: Virginia
Posts: 242
iTrader: (0)
Default

Took a look at the alternator idler pulley and that might be the problem, it might not be. It was kinda of freewheeling kind of loosely in comparison to the A/C idler and there was some bearing noise to it, so I have ordered a new pulley to see if that resolves the problem.
bimmern00b is offline   Reply With Quote
Old 05-06-2011, 05:49 PM   #15
zoner
Senior Member
 
zoner's Avatar
 
Join Date: Oct 2008
Location: Los Angeles, CA
Posts: 1,464
iTrader: (7)
Default

I would think that if it were anything running off of the drive belt, the noise would fluxuate at least a little with an increase/decrease in engine RPM, but perhaps not. You might want to try spraying some belt grip on the drive belt and see if that makes any difference in the pitch or intensity of the noise- I had a bad belt tensioner and a bad pulley and in both instances, the noise coming from either changed slightly once I sprayed the belt, and that's how I was able to isolate the source of the noise. Just a thought.
zoner is offline   Reply With Quote
Reply

Bookmarks

Tags
engine , noise


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Mystery noise from rear of car? B3n Misc 13 06-10-2011 04:40 AM
New with a '96 and have a mystery synth808 Personal bios and Introductions 5 09-04-2010 05:58 PM
Marvel Mystery Oil MyTi82 Engine 5 09-03-2009 09:14 PM
ASC+T Mystery! MPWR Misc 7 06-06-2009 04:56 AM
Mystery Noise from Diff Lou Differentials 1 06-27-2007 04:01 PM


All times are GMT +1. The time now is 11:38 AM.


.
Powered by site supporters
vBulletin Version 3.8.8
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©1999 - 2024, 318ti.org
© vBadvanced CMPS v3.2.2
[page compression: 126.09 k/149.81 k (15.83%)]

318ti.org does not warrant or assume any legal liability or responsibility for the accuracy, completeness, or usefulness of any information or products discussed.