Oh my God moment..dodged a bullet.
04-05-2009, 10:09 PM
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1994 E320 (current)
Oh my God moment..dodged a bullet.
Had to post this because I wouldn't have believed it if I hadn't went through it myself. (pics will come soon)
I recently finished a head gasket job on my e320 in which I also replaced my oil pressure sensor and various other parts. All was good until on day 3 of running it the oil pressure gauge quit working. It made me a bit nervous so I took off the oil fill cap to make sure I had oil flow and it all seemed well. After a couple days I started getting what I thought was cam noise and I started sweating bullets. On my way home from work on Thursday it got progressively louder and did so in a hurry. I diverted to my folks house and shut her down.
First order of business was to verify oil PSI. I modified an oil filter canister cap into a Oil PSI gauge (I will post pics of that later) I started her up and got 80 PSI immediately and the pressure bleed off at shutdown was a healthy 2-3 psi per second. So having verified healthy oil pump operation and good pressure and flow I started thinking maybe I was getting chain noise off a busted timing chain guide and I was misdiagnosing it. That is when I got the shock of my automotive life.
I took the valve cover off and started looking down the chain to see what was going on. I found a Cam shaft pulley bolt resting in a oil channel and thought that was a bit odd. Upon examination I had 1 cam sprocket bolt back out completely and was thrown up into the only place that kept it from falling down into the chain and causing a catastrophic event (how it rested in this precarious position is beyond comprehension). I had one of the two remaining bolts resting half out and the last just finger tight. So basically the cam sprocket was "wobbling" and smacking the chain around. Either I had my torque wrench set incorrectly or I missed the final tightening of the bolts completely. Either way I was shaking when I saw what was going on. From this point on every thing gets marked with paint marker after torquing and I will be much more nervous about my rebuilds. Stupid lucky me.
Pic taken during rebuild. the the culprit bolts are on the exhaust side sprocket (the 3 six point torx head). Getting three new bolts and a fresh pack of fruit of the looms on Monday.
I recently finished a head gasket job on my e320 in which I also replaced my oil pressure sensor and various other parts. All was good until on day 3 of running it the oil pressure gauge quit working. It made me a bit nervous so I took off the oil fill cap to make sure I had oil flow and it all seemed well. After a couple days I started getting what I thought was cam noise and I started sweating bullets. On my way home from work on Thursday it got progressively louder and did so in a hurry. I diverted to my folks house and shut her down.
First order of business was to verify oil PSI. I modified an oil filter canister cap into a Oil PSI gauge (I will post pics of that later) I started her up and got 80 PSI immediately and the pressure bleed off at shutdown was a healthy 2-3 psi per second. So having verified healthy oil pump operation and good pressure and flow I started thinking maybe I was getting chain noise off a busted timing chain guide and I was misdiagnosing it. That is when I got the shock of my automotive life.
I took the valve cover off and started looking down the chain to see what was going on. I found a Cam shaft pulley bolt resting in a oil channel and thought that was a bit odd. Upon examination I had 1 cam sprocket bolt back out completely and was thrown up into the only place that kept it from falling down into the chain and causing a catastrophic event (how it rested in this precarious position is beyond comprehension). I had one of the two remaining bolts resting half out and the last just finger tight. So basically the cam sprocket was "wobbling" and smacking the chain around. Either I had my torque wrench set incorrectly or I missed the final tightening of the bolts completely. Either way I was shaking when I saw what was going on. From this point on every thing gets marked with paint marker after torquing and I will be much more nervous about my rebuilds. Stupid lucky me.
Pic taken during rebuild. the the culprit bolts are on the exhaust side sprocket (the 3 six point torx head). Getting three new bolts and a fresh pack of fruit of the looms on Monday.
04-06-2009, 12:44 PM
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1994 E320 (current)
Got some interesting information about those bolts. Apparently you are supposed to replace them when you take them off. The manufacture suggestion to the dealerships is replace and not to reuse old bolts. Apparently I found out why.
And you can bet on the loctite.
04-09-2009, 02:32 AM
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Maybe those are one time use screws. That happened to me too last summer, but on the M119, but almost the same type design as the M104.
Buy new screws and some locktite (blue) as said ealier. Next time I have my valve covers off, or I have some free time, Im going to install new bolts with some blue locktite. It looks like we both dodged some bullets then.
I had to make a tool to get to mine. I replaced my motor mounts then needed to remove my valve covers which was very difficult because the motor was up about an inch higher- and tight to the firewall.
Buy new screws and some locktite (blue) as said ealier. Next time I have my valve covers off, or I have some free time, Im going to install new bolts with some blue locktite. It looks like we both dodged some bullets then.
I had to make a tool to get to mine. I replaced my motor mounts then needed to remove my valve covers which was very difficult because the motor was up about an inch higher- and tight to the firewall.
