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Low oil light flickers on, slight engine knock


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I have my Accord being looked at by a certified Honda mechanic, but still im worried. What happened is I was driving and my oil light started flickering and finally it just stayed on. I noticed that it does it as the engine gets warmed up, when i first start it i dont have any problems. But i do notice that as i drive with the oil light on the performance suffers, and i even began to hear a slight knocking in the engine. At that point i sent it in, cant afford an engine overhaul or a broken rod. So anyway the mechanic thinks its the oil sending unit, so replaced that, but light still comes on. He's going to take the oil pan off today and check some filter thats inside the pan itself (not the obvious oil filter, i just got all that changed with my oil change.) He thinks that filter is clogged and keeping the oil from reaching the top of the engine. Ive searched the internet, and everybody else who has this problem tends to say "bad oil pump". Im hoping for some clarity, because since he has the oil pump off it might be best to change it if its the problem. My car has 123k on it, i only paid 2,000 for it but at the same time i LOVE Hondas and i just want my car to be as solid as possible without breaking the bank. Any ideas? Thanks in advance!!!

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I am not certain what you mean by oil sending unit. The 2.7L C27A4's lubrication system consists of:


Oil Control Orfices*

Oil Pump

Oil Screen w/Inlet Pipe (this is what your mechanic calls a filter in the pan, it is just a screen, not a filter per se)

Oil Pass Pipe (high pressure outlet)

Oil Filter Base

Engine Oil Pressure Switch

Oil Filter

Baffle Plate

Oil Pan

Drain Bolt

and a whole gang of o-rings


* the Cylinder Heads have to be removed in order to get to these.


I have a 1997 EX-V6 (same 2.7L engine) and have worked with the lubrication system extensively. In fact, on my next timing belt change, I will be taking off the oil pump to change Crankshaft Seal that sits in the middle of it.


The Oil Pressure Switch interupts the ground connection to the Low Oil Pressure Indicator Light, it is open above 4.3psi; i.e. your light is supposed to come on when oil pressure drops below 4.3psi. You could check the pressure at the switch with an Oil Pressure Gauge, but you may find that the pressure really is below 4.3psi since you have the tell tale tapping that comes with low oil pressure in a C27A4. If the volume of oil is satisfactory, which should be verified by draining the motor and measuring the volume, then you have a: blockage, leakage, or the pump is failing. Among those three, the first two are the most likely. You or your mechanic should be looking into leaks and or blockages.


The Integrated Control Unit monitors the Engine Oil Pressure Switch and controls it in the following way: continuous flashing for a momentary loss of oil pressure, and solid light for a complete loss in oil pressure (you have to turn the car off and back on to reset the light).


We have hydraulic tappets that use oil pressure to push small rods that actuate our exhaust valves, tappets without enough hydraulic (oil) pressure is what you hear.

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what's the oil level when the light comes on? no leaks? could be the oil pump...


It could be the bearing being bad...causing the piston to make noise (the noise you described?)...


more details would be great...


gl :)

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you guys are awesome! I just wish i understood it all but im no mechanic by any means! Here are a few more details though. When i stop or go in reverse the light will flicker. When i give it gas the light stops flickering...for a while. Then it starts to flicker and eventually stays on. The part i had to get for it is a lil plug that goes into the oil pan...like it screws into it and it has a lil screw with a wire attached to it that supposedly controls that little light. as it said that was replaced but the light still came on. He's supposed to be changing that screen b/c he says that if its clogged and can cause thye oil pressure to drop, and keep the oil from reaching the top of the engine. Also something peculiar happened the other day. I was driving...about 40 mph and the car suddenly lost rpms, and cut off. I mean it didnt rev up or anything, just lost pressure and cut off. after i coasted to a stop i popped the hood, looked under it, didnt see anything crazy, so i turned the ignition and it started right up. And it hasnt done that again. That was so weird. Btw the oil light was on then, and it had too much oil in it, about a 1 1/2qts too much. Ideas?

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The engine shut-off is an electrical problem.


From what you describe, your mechanic replaced the Engine Oil Pressure Switch.


If this was happening to me, and I suspected the Oil Screen and/or Inlet Pipe, I would unbolt said screen/pipe from the Oil Pump, dismantle it, soak it down with Brake Cleaner (a mixture of hexanes), let it dry, blast it with compressed air, put in new o-rings and re-assemble/re-install the screen/pipe assembly.


I plan on doing what I described above when I change the Oil Pump Crankshaft Seal. I don't have any issues, but I have changed all the other oil seals and this one on the Oil Pump will be the last. I figured while I have the timing belt out and the Oil Pump out, I might as well change the o-rings on the low pressure side of the Oil Pump inlet.


You might want to look into cleaning the cam shaft hold-down, it channels oil into a tube that has small holes above the cam, they run the length of the cam and drop oil onto it. I believe this plays a roll in keeping oil on the hydraulic tappets.

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I don't know but it sounds like either what James mentioned or your oil pump is going bad. That is not a common item to fail, but it is possible. We have only done one on that generation Accord in the past four years.

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