BMW Luxury Touring Community banner

1 - 18 of 18 Posts

·
Registered
Joined
·
89 Posts
Discussion Starter · #1 ·
My '99 LT (65k miles) suddenly sounds like a Diesel. I also hear a distinct buzzing tune that plays along with the engine up until 3-4k rpm or so.

Info from the site points to a leaking exhaust, but I cannot find the leak visually. It does not appear to be coming from the weld behind the passenger footpeg. There doesn't SEEM to be any soot around any of the head flanges, but it's hard to tell. I can look at them with the bike running, and nothing is obvious. No loose headers. I don't notice any change in performance, just the increase in engine noise and the buzz.

I'll be able to pull the plastic for a better look later in the week, but is there anything else that might cause this? I recently changed the oil. No leaks or drips. And should I park the bike? I have a 300 mile trip ahead of me and I would much prefer to ride.

Thanks!
 

·
Registered
Joined
·
280 Posts
JGroves said:
My '99 LT (65k miles) suddenly sounds like a Diesel. I also hear a distinct buzzing tune that plays along with the engine up until 3-4k rpm or so.

Info from the site points to a leaking exhaust, but I cannot find the leak visually. It does not appear to be coming from the weld behind the passenger footpeg. There doesn't SEEM to be any soot around any of the head flanges, but it's hard to tell. I can look at them with the bike running, and nothing is obvious. No loose headers. I don't notice any change in performance, just the increase in engine noise and the buzz.

I'll be able to pull the plastic for a better look later in the week, but is there anything else that might cause this? I recently changed the oil. No leaks or drips. And should I park the bike? I have a 300 mile trip ahead of me and I would much prefer to ride.

Thanks!
While working in the dealerships, we would use a soapy water mix and spray around the exhaust to check for leaks.
Also works for intake leaks too, the idle will drop when sprayed around the intake.
 

·
Registered
Joined
·
89 Posts
Discussion Starter · #3 ·
Hollywood said:
While working in the dealerships, we would use a soapy water mix and spray around the exhaust to check for leaks.
Also works for intake leaks too, the idle will drop when sprayed around the intake.
I'll try that. I was expecting a crack or loose connection to be obvious. It sounds like that may not be the case...

Thanks for the idea!
 

·
Registered
Joined
·
164 Posts
Exhaust gaskets are leaking.....

I just changed mine at 47k on a 2005
was making a buzzing whisilling noise
around 3500 - 4000 +

pull the bottom plastic only on exhaust side
look for black exhaust blow by around the pipes

that is the exhaust gasket that is leaking

no worries order all 4 of the gaskets
and a new stud or 2
and all of the nuts
 

·
Registered
Joined
·
89 Posts
Discussion Starter · #5 ·
I hope they don't take as long to get as the brake line I bought in April...

Thanks for the tips.

Jeff
 

·
Registered
Joined
·
164 Posts
# 2 gasket almost gone in one place on mine

so i replaced them all.....

i looked and found no maintenance interval on
exhaust gaskets
not even "check tightness on this fastener at 000000 miles".

replaced all 4 gaskets 2 studs and all the nuts...

re torquing without gaskets at that point was pointless

If JGroves gaskets are compromised ( and they are makeing a whisling or buzzing noise) re torquing his would be pointless also......... IMHO
 

·
Registered
Joined
·
12,165 Posts
Loosen all the exhaust nuts on the headers so that the exhaust can drop down just a little, then try to turn all the flanges. If one or more turn any at all, the welds inside them where the pipe is welded is broken. This has happened on several, mine one of them.

If broken, easily re-welded.
 

·
Registered
Joined
·
89 Posts
Discussion Starter · #8 ·
Ok, so I went to the fiche to get the part #'s for the exhaust gaskets and studs/nuts. I couldn't find part #'s for the studs. I searched for "exhaust stud" on this site and found all the threads I wish I had found when searching for "exhaust leak". So anyway, thanks to those with advice and sorry for what has turned out to be a repeat of another recent thread.

But...

What is the part # for the studs? O-ring and nuts show up on exhaust system fiche. I can't find the studs there or in the "engine" section. And of course I could call the dealership for this info, but I know someone else knows and is dying to tell...

Thanks again,
Jeff
 

·
Premium Member
Joined
·
4,886 Posts
When replacing the O ring gaskets (I'm assuming you are talking about the copper crush ones) put a little grease on them before trying to balance all four at one time. Keeps them from falling off. I spent quite a bit of time learning this....
 

·
Registered
Joined
·
57 Posts
Timely Thread

I could use some advise while we are on the subject.

I have a 99lt that sounds like the bottom end is falling out of it when you crack the throttle hard from a idle. If I roll on the throttle it is smooth and quiet through the entire rpm range. Only happens when you nail it. It sounds low, tinny and in front of the peg area. Almost like a lose baffle or rattling skid plate. I have tried to bumb-hit everything I could get to with the tupperware on, but can not find any rattles. I am thinking exhaust flanges, but would like to know what you guys think? It only has 33,000 miles and runs fine. I may be putting it up for sale and need to get this fixed.

Any sugguestions?

Thanks
Pat :confused:
 

·
Registered
Joined
·
13,451 Posts
Re: Timely Thread

Patdcop said:
I could use some advise while we are on the subject.

I have a 99lt that sounds like the bottom end is falling out of it when you crack the throttle hard from a idle. If I roll on the throttle it is smooth and quiet through the entire rpm range. Only happens when you nail it. It sounds low, tinny and in front of the peg area. Almost like a lose baffle or rattling skid plate. I have tried to bumb-hit everything I could get to with the tupperware on, but can not find any rattles. I am thinking exhaust flanges, but would like to know what you guys think? It only has 33,000 miles and runs fine. I may be putting it up for sale and need to get this fixed.

Any sugguestions?

Thanks
Pat :confused:
I'd start where the large tupperware panels meet the silver bottom ones in the front. If there's nothing there, cut some soft side of velcro to size (strips) and slap it on.



100% free webcam site! | Awesome chicks and it is absolutely free! | Watch free live sex cam - easy as 1-2-3
 

·
Registered
Joined
·
12,165 Posts
Re: Timely Thread

Patdcop said:
I could use some advise while we are on the subject.

I have a 99lt that sounds like the bottom end is falling out of it when you crack the throttle hard from a idle. If I roll on the throttle it is smooth and quiet through the entire rpm range. Only happens when you nail it. It sounds low, tinny and in front of the peg area. Almost like a lose baffle or rattling skid plate. I have tried to bumb-hit everything I could get to with the tupperware on, but can not find any rattles. I am thinking exhaust flanges, but would like to know what you guys think? It only has 33,000 miles and runs fine. I may be putting it up for sale and need to get this fixed.

Any sugguestions?

Thanks
Pat :confused:
That is very similar to what I had for 3-4 months before I discovered the welds inside the header flanges broken. Try my earlier test: Loosen all the header nuts until the header is slightly loose in the head and try to rotate all the flanges. If broken, whey will rotate around the pipe as far as the studs allow.
 

·
Registered
Joined
·
6,424 Posts
dandiver said:
When replacing the O ring gaskets (I'm assuming you are talking about the copper crush ones) put a little grease on them before trying to balance all four at one time. Keeps them from falling off. I spent quite a bit of time learning this....
I heard that's a sympton from lack of oxygen, i.e. jumping out of airplanes comes to mind. :histerica
 

·
Premium Member
Joined
·
4,886 Posts
Not quite as crowded up there as it is on the highways........
 

·
Registered
Joined
·
57 Posts
Thanks David, I will try that this weekend. Griff, the plastics tight as I have put 3m HB tape along the seem. I just hate laying on my back paying homage to the girl. The things they do for attention. :p
 

·
Registered
Joined
·
89 Posts
Discussion Starter · #17 · (Edited)
Gaskets came in today, so I thought I'd remove the exhaust and see if I could diagnose the problem.

Everything came apart nicely. Seven of the eight studs came out of the head, but threads all look nice. Fine. Removed exhaust and heat shield to inspect. Hmm. The exhaust was very clean. I could find no trace of soot anywhere. All welds looked good. Flanges were all tight with no signs of soot. So I figure maybe one of the gaskets was leaking (though there were no signs of rupture or broken seal area on the old gaskets).

I cleaned everything up and reassembled, new copper gaskets, torqued exhaust-to-C.H. studs to 22 Nm per manual. No change. Still sounds like a diesel, still has a tinny buzz until around 4k rpm.

Could the leak just be that hard to find? Does this sound like it could be anything else?

My next step is to let everything cool off, soak it all with soapy water, turn the engine over and hope for bubbles.

Also... I ordered some spare studs and nuts (just in case). The nuts they sent are much smaller than the originals (not the ID, just overall length). Did I order the wrong part or is this just the replacement? They are copper, like the originals.

Thanks again for the advice!
 
1 - 18 of 18 Posts
Top