D2 lower engine noise ?

adisco

Member
Feb 27, 2019
13
2
SLC
Hey there guys. New to the site. Joined because I just bought an 02 D2.
Making a knocking noise from the lower part of the engine. More audible from the side and underneath the car. Hit it with a stethoscope to make sure.

Only happens once the engine is warmed up. Only happens at idle speed and gentle acceleration. Goes away completely when decelerating.
The knock makes it sound like a diesel.

I am planning to remove the oil pan because it is due for an oil change anyways. Wanted to ask what in there specifically should I be checking for this kind of noise?
Any help/advice upfront would be appreciated.... I won't be dropping thousands of dollars and man hours to track down a knock that isn't hurting anything... currently.
Thanks.
 

jprover2

Well-known member
Apr 8, 2017
108
2
Birmingham,Al
If it sounds like the lower end, it's either a main bearing or a liner is slipped. You could pull the valve covers and remove the fuel pump relay, have someone turn the engine over and see if the valve train is working properly. Other than that it is pulling the heads or engine.
 

adisco

Member
Feb 27, 2019
13
2
SLC
Forgive the ignorance here but wouldn’t a slipped liner beat the heads causing more of an upper engine noise?
I’m hoping it is a bearing, any way to know that by looking at the bearings rather than replace them? As obviously I couldn’t test the cause of the knock with the engine apart.
 

jprover2

Well-known member
Apr 8, 2017
108
2
Birmingham,Al
Sound can travel in strange ways inside an engine, I have heard a slipped liner in a running engine that appeared to be from the bottom. If you're gonna have the oil pan removed, look at the oil pickup screen and inspect for metal parts caught by screen. You could remove a main cap one at a time and inspect the bearings.
 

Swedjen2

Well-known member
Sep 12, 2018
158
12
California
Hey there guys. New to the site. Joined because I just bought an 02 D2.
Making a knocking noise from the lower part of the engine. More audible from the side and underneath the car. Hit it with a stethoscope to make sure.

Only happens once the engine is warmed up. Only happens at idle speed and gentle acceleration. Goes away completely when decelerating.
The knock makes it sound like a diesel.

I am planning to remove the oil pan because it is due for an oil change anyways. Wanted to ask what in there specifically should I be checking for this kind of noise?
Any help/advice upfront would be appreciated.... I won't be dropping thousands of dollars and man hours to track down a knock that isn't hurting anything... currently.
Thanks.
What's your milage? Do you know the service history ? What oil is in there? What weight?
 

adisco

Member
Feb 27, 2019
13
2
SLC
128k. Unknown service history. Planning to do a rotella oil change soon, hoping that solves the issues. I have a 20% solution marvel mystery oil in the engine now, just need to run it a while longer to get it cleaned up before the oil change.
I did find that there was about a quart of oil overfilled when I checked. Drained that off to add the marvel in.
 

squirt

Well-known member
Nov 13, 2008
797
2
Los Angeles
Are you absolutely certain that it's not an exhaust leak at a manifold gasket? It's a common issue, and sounds very similar.
 

jprover2

Well-known member
Apr 8, 2017
108
2
Birmingham,Al
I am not certain... Good way to test for that?
When engine is cold, have the hood up and stand at the fender. Have someone trustworthy fire the engine use your hands to feel, "not touch", around the manifold where it's bolted to the head. Once its too hot, shut down engine let cool and repeat. You should be able to feel exhaust gas hitting your hand.
Also look for black soot in the area where leak is
 

adisco

Member
Feb 27, 2019
13
2
SLC
Thanks for the replies guys. I scanned the truck and have a bunch of codes throwing from mostly O2 problems. Getting a few engine misfire codes as well.
Checked around the heads per jprover's instruction. No manifold leaks as far as I can tell. Bolts and nuts were tight.
Rotella oil change seems to have done away with the knocking sound.
 
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mlnnc

Well-known member
Mar 23, 2008
187
2
Charlotte
If you have a shop vac another way to check for exhaust leaks is move the vac hose to the exhaust port of the shop vac and slip the other end of the hose over the tail pipe. Be ready with a spray bottle of soapy water, then turn on the vac. Spray the soapy water around the exhaust system gaskets. Look for bubbling of the soapy water to locate leaks (or to confirm there are none).
 
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kade

Well-known member
Oct 15, 2013
228
5
Upstate, SC
I am not certain... Good way to test for that?

I recently found a leak by blowing air into the tail pipe. Simply a running leaf blower, lowest pressure, not full blast.

While exhaust is being blown into, On a cold engine, not running—— spray exhaust joints with soapy water mixture. If air is leaking it will bubble up noticeably.