Loud Knocking Engine
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Loud Knocking Engine
Vehicle is a 1987 560 SEL with 169000 miles. New timing chain, timing chain tensioner, and top three guide rails at 167000 miles (6 months ago).
While driving home from a short 5 mile trip I noticed the coolant temperature was up close to 100 degrees, so I stopped and topped off coolant reservoir with about 20 ounces of water. Now driving at 45 mph I notice the coolant temp rise up past 120 deg (red zone) in less then a mile. I drove another ½ mile to my house and let it idle, turned heater on high, opened the hood, and went to get some water. Took me 3-5 minutes to get some water and now the engine is making a LOUD KNOCKING noise.
It’s hard to pin point the exact location of the KNOCKING sound, but I’m 95% sure it’s coming from the engine on passenger side. I removed the passenger side cam/valve cover and everything looked normal, so I pulled the spark plugs and the plug closest to the firewall is wet and doesn’t look like it‘s been firing.
Does anybody know what the KNOCKING noise might be or have any suggestions on what I should do?
While driving home from a short 5 mile trip I noticed the coolant temperature was up close to 100 degrees, so I stopped and topped off coolant reservoir with about 20 ounces of water. Now driving at 45 mph I notice the coolant temp rise up past 120 deg (red zone) in less then a mile. I drove another ½ mile to my house and let it idle, turned heater on high, opened the hood, and went to get some water. Took me 3-5 minutes to get some water and now the engine is making a LOUD KNOCKING noise.
It’s hard to pin point the exact location of the KNOCKING sound, but I’m 95% sure it’s coming from the engine on passenger side. I removed the passenger side cam/valve cover and everything looked normal, so I pulled the spark plugs and the plug closest to the firewall is wet and doesn’t look like it‘s been firing.
Does anybody know what the KNOCKING noise might be or have any suggestions on what I should do?
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Joined: Oct 2007
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380se
Probably a broken rod. Don't start it or drive it until you have had it checked out. You could drop the oil pan and take a look. A broken rod is not always the end of an engine if it is caught right away. But combined with the overheating that is not a good combo.
Last edited by elolson; Nov 3, 2007 at 12:10 AM.
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Joined: Nov 2001
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From: North Bay Area, California
2001 E320
Vehicle is a 1987 560 SEL with 169000 miles. New timing chain, timing chain tensioner, and top three guide rails at 167000 miles (6 months ago).
While driving home from a short 5 mile trip I noticed the coolant temperature was up close to 100 degrees, so I stopped and topped off coolant reservoir with about 20 ounces of water. Now driving at 45 mph I notice the coolant temp rise up past 120 deg (red zone) in less then a mile. I drove another ½ mile to my house and let it idle, turned heater on high, opened the hood, and went to get some water. Took me 3-5 minutes to get some water and now the engine is making a LOUD KNOCKING noise.
It’s hard to pin point the exact location of the KNOCKING sound, but I’m 95% sure it’s coming from the engine on passenger side. I removed the passenger side cam/valve cover and everything looked normal, so I pulled the spark plugs and the plug closest to the firewall is wet and doesn’t look like it‘s been firing.
Does anybody know what the KNOCKING noise might be or have any suggestions on what I should do?
While driving home from a short 5 mile trip I noticed the coolant temperature was up close to 100 degrees, so I stopped and topped off coolant reservoir with about 20 ounces of water. Now driving at 45 mph I notice the coolant temp rise up past 120 deg (red zone) in less then a mile. I drove another ½ mile to my house and let it idle, turned heater on high, opened the hood, and went to get some water. Took me 3-5 minutes to get some water and now the engine is making a LOUD KNOCKING noise.
It’s hard to pin point the exact location of the KNOCKING sound, but I’m 95% sure it’s coming from the engine on passenger side. I removed the passenger side cam/valve cover and everything looked normal, so I pulled the spark plugs and the plug closest to the firewall is wet and doesn’t look like it‘s been firing.
Does anybody know what the KNOCKING noise might be or have any suggestions on what I should do?
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Joined: May 2006
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Richard,
The temp was still about 120 deg after getting water. There is no water/coolant in oil.
Oil pressure is 2 bar when I turn engine over with coil wire unplugged.
I decided to check the hydraulic valve clearance compensating elements (05-211) since I had cam/valve covers off. While checking each compenstor I was able to push down the compensator for the exhaust valve at cylinder #4 and now it is stuck down and the rocker arm is loose. The manual say's to replace any compensator that can be pushed down faster then the others.
Could this be causing the loud KNOCKING noise?
How do I get compensator unstuck? Can I turn engine over with the rocker arm being so loose?
Is the "hydraulic valve clearance compensating element" the same or another name for the "Cam Follower", "Hydraulic Lifter", or "Hydraulic Ball Stud Assembly"?
The temp was still about 120 deg after getting water. There is no water/coolant in oil.
Oil pressure is 2 bar when I turn engine over with coil wire unplugged.
I decided to check the hydraulic valve clearance compensating elements (05-211) since I had cam/valve covers off. While checking each compenstor I was able to push down the compensator for the exhaust valve at cylinder #4 and now it is stuck down and the rocker arm is loose. The manual say's to replace any compensator that can be pushed down faster then the others.
Could this be causing the loud KNOCKING noise?
How do I get compensator unstuck? Can I turn engine over with the rocker arm being so loose?
Is the "hydraulic valve clearance compensating element" the same or another name for the "Cam Follower", "Hydraulic Lifter", or "Hydraulic Ball Stud Assembly"?
