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Unread 10-29-2012, 12:33 AM   #1
baritone_mike
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Oil smells like exhaust? And engine tick/knock.

So I changed my oil friday night and it smells like exhaust (not gas). My exhuast smells like exhaust, not oil or gas and the Jeep does not smoke. Is this a problem, the oil had about 3,000 miles on it. Also anyone follow the owners manual recomended 15,000 mile oil change?

I will get a video of my engine up with in the next couple of days, but it is making a couple noises that are worrying me. The first I think is the valves, it sounds like it is coming from the vavle cover and is a slight rythmic ticking noise, like someone drumming their fingers (4 quick ticks then a slight pause, then 4 quick ticks and a slight pause) The 2nd noise is what is really worring me, it sounds like it is comming from the bottom of the engine and is a consistant heavy tick/light knock that changes with RPM, and is most noticeable at idle and is drowned out or goes away above 1,500rpm. My exhaust around the cat and muffler make the same noise so it may just be echoing throught he exhaust pipe?

The engine runs great, and there was nothing unusual in the oil. The oil pressure gauge reads at the line above 40psi all of the time with a slight increase in the higher RPM's (above 2500rpm) The Jeep has 171,000 miles on it.

Any ideas?

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Unread 10-29-2012, 12:36 AM   #2
dimatrod
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Quote:
Originally Posted by baritone_mike View Post
So I changed my oil friday night and it smells like exhaust (not gas). My exhuast smells like exhaust, not oil or gas and the Jeep does not smoke. Is this a problem, the oil had about 3,000 miles on it. Also anyone follow the owners manual recomended 15,000 mile oil change?

I will get a video of my engine up with in the next couple of days, but it is making a couple noises that are worrying me. The first I think is the valves, it sounds like it is coming from the vavle cover and is a slight rythmic ticking noise, like someone drumming their fingers (4 quick ticks then a slight pause, then 4 quick ticks and a slight pause) The 2nd noise is what is really worring me, it sounds like it is comming from the bottom of the engine and is a consistant heavy tick/light knock that changes with RPM, and is most noticeable at idle and is drowned out or goes away above 1,500rpm. My exhaust around the cat and muffler make the same noise so it may just be echoing throught he exhaust pipe?

The engine runs great, and there was nothing unusual in the oil. The oil pressure gauge reads at the line above 40psi all of the time with a slight increase in the higher RPM's (above 2500rpm) The Jeep has 171,000 miles on it.

Any ideas?
AFAIK oil should be changed every 3,000 miles or so, not 15,000... Might be that it's really burned off.
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Unread 10-29-2012, 12:52 AM   #3
baritone_mike
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The owners manual says 15,000 miles unless you drive in dusty conditions then it should be changed twice as often (7,500 miles) I change it at about 3000 miles, and have done 3 oil changes since I got the Jeep, I don't know what the PO did, the oil was not excessively dirty and still had a brown color to it when I changed it.
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Unread 10-29-2012, 07:42 AM   #4
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Quote:
Originally Posted by baritone_mike
The owners manual says 15,000 miles unless you drive in dusty conditions then it should be changed twice as often (7,500 miles) I change it at about 3000 miles, and have done 3 oil changes since I got the Jeep, I don't know what the PO did, the oil was not excessively dirty and still had a brown color to it when I changed it.
Just changed mine yesterday had the exhaust smell but ibthink its from my straight pipes is all but i always get exhaust smell when doing so im not sure but i would say you are fine because when i change the oil in my grams 2004 ssr it smells the same and thats a new engine supercharger etc
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Unread 10-29-2012, 09:28 AM   #5
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just checked my owners manual for my 87. the oil change interval is 7,500 miles, not 15,000. IMHO thats still way to long, 3,000 or less is much better.
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Unread 10-29-2012, 09:36 AM   #6
CactusMan
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yea even 7500 is pushing it in my book. 4k max... its what like $25 for an oil change? rather pay that than replace engine internals...
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Unread 10-29-2012, 09:53 AM   #7
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Originally Posted by CactusMan
yea even 7500 is pushing it in my book. 4k max... its what like $25 for an oil change? rather pay that than replace engine internals...
Ya 3 bucks for oil filter 22 for mobil 1 10w30
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Unread 10-29-2012, 10:22 AM   #8
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I change every 3k. Maybe a few miles over. But never more than a hundred or so. Ill change it early if i think i wont be able to get to it.
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Unread 10-29-2012, 10:56 AM   #9
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Check your PCV valve and make sure it's breathable - it may not be working to remove the gases from the crankcase

A 4cyl with 171k miles is going to make noise - if it runs good, keep driving it
Valve ticking isn't a bid deal, but the low end could be trouble in the future if you don't investigate it
Get an engine stethoscope (preferred method) or a broom handle and listen to the inside of your engine
It will tell you wonders
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Unread 10-29-2012, 05:16 PM   #10
baritone_mike
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Originally Posted by zeus87gn View Post
Check your PCV valve and make sure it's breathable - it may not be working to remove the gases from the crankcase

A 4cyl with 171k miles is going to make noise - if it runs good, keep driving it
Valve ticking isn't a bid deal, but the low end could be trouble in the future if you don't investigate it
Get an engine stethoscope (preferred method) or a broom handle and listen to the inside of your engine
It will tell you wonders
The PCV valve is only a couple of months old and so is the crank case breather on the back of the valve cover, and they both work. The oil on top of the vavle cover is just what I spilt when I was changing the oil, it was dry before the oil change.

Here is the noise, the valves were not ticking as bad in this video but are still making some noise which is probably normal. You can hear the heavier ticking/knocking noise though. The camera picks up a lot of the white noise from the fan and stuff that you don't hear in real life so the ticking/knocking is louder in comparison to the other noises. I do have an exhaust leak in the front of the muffler where it joins the rest of the exhaust but I don't think this is causing the noise. The noise I hear in the cat area is the same as in the video, so it may just be coming from the engine?

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Unread 10-29-2012, 06:42 PM   #11
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Originally Posted by baritone_mike View Post
The PCV valve is only a couple of months old and so is the crank case breather on the back of the valve cover, and they both work.
Ok, is there any vacuum at the inlet of the breather?

Quote:
Originally Posted by baritone_mike View Post
Here is the noise.....
I hear an old 4 banger with lots of valve train noise
Someone with more familiar ears will have to chime in to give you a better opinion
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Unread 10-29-2012, 06:55 PM   #12
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Originally Posted by zeus87gn View Post
Ok, is there any vacuum at the inlet of the breather?


I hear an old 4 banger with lots of valve train noise
Someone with more familiar ears will have to chime in to give you a better opinion
There is not supposed to be any vacuum to the breather, it just hooks to the air box and vents gases the PCV Valve can't keep up with (At least this is what I gathered when I was trying to stop the oil cap from leaking, I ended up just putting two gaskets on it). The lines are not clogged and you can easily blow through them. The PCV Valve does suck.

Is it just noise or is it the sound of something trying to get out? If it is just noise I really don't care, if it is something trying to get out and I can fix it with out a full rebuild I would rather fix it then wait for it to escape.
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Unread 10-30-2012, 01:29 AM   #13
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hmm yea it does have alot of valve train noise. when an engine is cold its not too bad to have but if its like that when its all warmed up and hot....

usually rod knock will be noticeable when you snap the throttle on the accel and deceleration you will hear a deep thudding sound. need to take another video of the throttle being snapped and the throttle being slowly increased to a safe like 2-3K rpm then let off.
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Unread 10-30-2012, 07:18 AM   #14
zeus87gn
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Quote:
Originally Posted by baritone_mike View Post
There is not supposed to be any vacuum to the breather, it just hooks to the air box and vents gases the PCV Valve can't keep up with (At least this is what I gathered when I was trying to stop the oil cap from leaking, I ended up just putting two gaskets on it). The lines are not clogged and you can easily blow through them. The PCV Valve does suck.
There should be vacuum at the inlet of the breather bacuase the PCV valve will create it through the crankcase - sometimes (especially in older engines)it won't happen until the engine speed is elevated - once the throttle body begins to open, the PCV valve opens and creates that vacuum - the PCV valve is typically closed at idle speed - if the PCV can't keep up with the crankcase gasses, you have crankcase pressurization due to old pistion rings and valve guides that are 170k miles old

Quote:
Originally Posted by baritone_mike View Post
Is it just noise or is it the sound of something trying to get out? If it is just noise I really don't care, if it is something trying to get out and I can fix it with out a full rebuild I would rather fix it then wait for it to escape.
My guess is it's just noise - what weight oil do you run?
It's quite difficult to diagnose a bottom end knock without being right there at the vehicle unless the sound is quite pronounced - i didn't hear anything that obvious in your video - I wonder of there is a valve lash adjustment for the 4cyl?
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Unread 10-30-2012, 09:05 AM   #15
baritone_mike
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Originally Posted by CactusMan View Post
hmm yea it does have alot of valve train noise. when an engine is cold its not too bad to have but if its like that when its all warmed up and hot....

usually rod knock will be noticeable when you snap the throttle on the accel and deceleration you will hear a deep thudding sound. need to take another video of the throttle being snapped and the throttle being slowly increased to a safe like 2-3K rpm then let off.
This was at operating temperature after a 45 minute drive. There is no deep thudding sound, on acceleration or deceleration. I guess I can take another video though.

Quote:
Originally Posted by zeus87gn View Post
There should be vacuum at the inlet of the breather bacuase the PCV valve will create it through the crankcase - sometimes (especially in older engines)it won't happen until the engine speed is elevated - once the throttle body begins to open, the PCV valve opens and creates that vacuum - the PCV valve is typically closed at idle speed - if the PCV can't keep up with the crankcase gasses, you have crankcase pressurization due to old pistion rings and valve guides that are 170k miles old


My guess is it's just noise - what weight oil do you run?
It's quite difficult to diagnose a bottom end knock without being right there at the vehicle unless the sound is quite pronounced - i didn't hear anything that obvious in your video - I wonder of there is a valve lash adjustment for the 4cyl?
I will check the breather for vacuum today, not that I could fix it if it didn't hvae vacuum. I run 10w-30.
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