rcmaniac791
Well-Known Member
- Joined
- Nov 4, 2015
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Well, here it goes:
The car (1984 chrysler fifth avenue, stock 318, stock drivetrain, just hit 80,000 miles) has been running great until about a month ago, when I accidentally put mobil semi-synthetic 10w-30 in the car during an oil change. (they need to label the bottles better). When I started the car to drive it afterwards, I noticed a very mild knocking sound, kinda sounded like rod knock, could have been the fuel pump, not sure. I didn't really worry about it. I should also say that the noise is only audible when at idle, mostly at idle in gear.
For the month that I had the semi-synthetic in the car, I also noticed that after sitting for more than an hour, the oil pressure light would take about 4 seconds to turn off when the engine was started, but when the car was driving (I put 800 miles on that oil) the oil pressure light was always off. I fixed the start-up oil pressure this last weekend when I did another oil change back to the mobil super conventional 10w-30 that I have been running for the last 6 years without problems. I ran the car for a good amount of time right after the change and I did not hear any noise. The car sounded normal. Oil pressure was now back to normal. I also did not see any aluminum glitter in the oil that I drained out.
Well, today the noise is back. Still faint, and still only audible when the engine is warm and idling in gear. Today, I removed all the accessories and the fuel pump and ran the engine for a short period of time, and the noise did not change. I also pulled each spark plug wire one by one and not a single one changed the noise. The car is running and driving completely normal, no oil consumption, no smoke, no blow-by, nothing. Just a very faint knocking noise at idle.
I should also mention that the car has been meticulously maintained and it's had oil changed religiously every 3,000 miles. The knock seems to be coming from the front of the engine, which leads me to think timing chain, but I'm not sure. The volume of the knock is not super consistent, it's just there. Also, when brake-standing the car, the engine sounds completely normal.
Anyways, Thanks for reading all that. I hope that my fears are nothing and I'm just over-reacting to something silly. Let my know what you guys thing.
-Jon
The car (1984 chrysler fifth avenue, stock 318, stock drivetrain, just hit 80,000 miles) has been running great until about a month ago, when I accidentally put mobil semi-synthetic 10w-30 in the car during an oil change. (they need to label the bottles better). When I started the car to drive it afterwards, I noticed a very mild knocking sound, kinda sounded like rod knock, could have been the fuel pump, not sure. I didn't really worry about it. I should also say that the noise is only audible when at idle, mostly at idle in gear.
For the month that I had the semi-synthetic in the car, I also noticed that after sitting for more than an hour, the oil pressure light would take about 4 seconds to turn off when the engine was started, but when the car was driving (I put 800 miles on that oil) the oil pressure light was always off. I fixed the start-up oil pressure this last weekend when I did another oil change back to the mobil super conventional 10w-30 that I have been running for the last 6 years without problems. I ran the car for a good amount of time right after the change and I did not hear any noise. The car sounded normal. Oil pressure was now back to normal. I also did not see any aluminum glitter in the oil that I drained out.
Well, today the noise is back. Still faint, and still only audible when the engine is warm and idling in gear. Today, I removed all the accessories and the fuel pump and ran the engine for a short period of time, and the noise did not change. I also pulled each spark plug wire one by one and not a single one changed the noise. The car is running and driving completely normal, no oil consumption, no smoke, no blow-by, nothing. Just a very faint knocking noise at idle.
I should also mention that the car has been meticulously maintained and it's had oil changed religiously every 3,000 miles. The knock seems to be coming from the front of the engine, which leads me to think timing chain, but I'm not sure. The volume of the knock is not super consistent, it's just there. Also, when brake-standing the car, the engine sounds completely normal.
Anyways, Thanks for reading all that. I hope that my fears are nothing and I'm just over-reacting to something silly. Let my know what you guys thing.
-Jon
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