Oil light on during idle after warmup
 

Hi,

92 Accord, 323k miles. Oil light comes on after the engine is warmed up, but only at idle.
It usually only comes on after being on the highway for awhile and then coming to a stoplight.

I just replicated the behavior by getting the engine completly warmed up, then revving to 5k rpms for 30 seconds. Oil light then comes on at idle, goes off as soon as you raise the rpms above 1100 or so.

I adjusted the idle up a bit, because it seemed to want to stall in these situations.

Oil level is fine.

Any ideas on what could be causing this?

Thanks,
Scott

Re: Oil light on during idle after warmup
 

sounds like a worn out oil pump. clearances are too big inside to be able to keep oil pressure up at idle. when spinning it faster, revin it up, its easier for it to build pressure. take out your OPS and put in a gauge and drive it around checking it cold to hot.

Re: Oil light on during idle after warmup
 

could be the pump but I would replace the sending unit first and see if that solves the problem. replacing oil pump = remove oil pan and change pump out.....

Re: Oil light on during idle after warmup
 

Yeah, looked it up. That's gonna suck if I need the oil pump replaced.
Wish I had known at 300k miles when the timing belt was done.

So, on the oil pressure sending unit...
1) When I take it out is oil gonna flow out the hole, if it hasn't been drained first?
2) Do I need a special thread sealant type stuff?
3) Do I need a special socket to remove the sending unit?

Thanks

Re: Oil light on during idle after warmup
 

i think the problem is, that it has alot of miles on it, f.e. 300k like you said. after that many miles, the oil passages, bearing clearences and galleries start to wear out. i would first try a thicker oil, f.e. if your using 5w-20, then that means when the oil warms up its only 5 thick. try going with like a 10w-20 or something or more common one is 10w-30. that should work as well, but its a cheaper fix than replacing oil sending units and oil pumps. this isnt a problem really. the car is driving at 300k miles you should be proud. its a veteran on the road. it has a right to be a little worn inside.

Re: Oil light on during idle after warmup
 

I also agree to try using a thicker oil, as the problem is probably due to wear.

Re: Oil light on during idle after warmup
 

Gregp09 what are you talking about when you say, "when the oil warms up it is only 5 thick"???? that doesn't make any sense

Re: Oil light on during idle after warmup
 

I wasnt sayin to just replace the oil pump, for it is a big job. Im saying to check your oil pressure at different temps, rpm and load ranges. this will tell you if you have a problem with the pump or if its is the sending unit

Re: Oil light on during idle after warmup
 

I think he means it has the Viscosity of 5 when its warmed up...

Thanks Wikipedia:

Viscosity is a measure of the resistance of a fluid which is being deformed by either shear stress or extensional stress. In everyday terms (and for fluids only), viscosity is "thickness." Thus, water is "thin," having a lower viscosity, while honey is "thick," having a higher viscosity. Viscosity describes a fluid's internal resistance to flow and may be thought of as a measure of fluid friction. For example, high-viscosity magma will create a tall, steep stratovolcano, because it cannot flow far before it cools, while low-viscosity lava will create a wide, shallow-sloped shield volcano. Put simply, the less viscous something is, the greater its ease of movement (fluidity). [1] All real fluids (except superfluids) have some resistance to stress, but a fluid which has no resistance to shear stress is known as an ideal fluid or inviscid fluid. The study of viscosity is known as rheology.

Re: Oil light on during idle after warmup
 

You sir made me laugh. 5W-20, when the oil is cold (i.e. in morning before first start) it's viscosity is 5 weight, once the oil reaches its operating temp, its viscosity will be 20 Weight (thicker).

Using 10w-30 would do jack shit for a car that has done that milage, 20W-50 would be a go.

Re: Oil light on during idle after warmup
 

^^ now you said that I understand what Mavvrik was trying to say..... I lol'n at myself right now for not reading why mavvrik asked.... DOH!!

Re: Oil light on during idle after warmup
 

Hahah, ok, I had to ask/bring it up. However, you do know that the "W" in (x)W doesn't stand for weight??

Re: Oil light on during idle after warmup
 

Since I cannot say 'W' in written form, I just call it 'W'eight since every one calls it that way even though it is wrong.

W-means Winter. This is your oil viscosity during winter or generally when it is on cold temperature.

Re: Oil light on during idle after warmup
 

Ok, lol, just amkin sure everyone knew that it stood for Winter, not weight

Re: Oil light on during idle after warmup
 

10w30 is in it as per owners manual.
I'll try a thicker oil on my next change.

Probably easier to just replace the sending unit than check oil temp at different rpms etc.So, on the sending unit.
Can anyone answer my install questions?
1) When I take it out is oil gonna flow out the hole, if it hasn't been drained first?
2) Do I need a special thread sealant type stuff?
3) Do I need a special socket to remove the sending unit?

Thanks,
Scott

Re: Oil light on during idle after warmup
 

1) No, oil wont flow out the hole unless the engine is running and pumping oil around the engine
(well not an amount to be concerned about anyways - there will be a little bit of oil)
2)Don't quote me on this but I think the new sensor will come with a sealant on the tapered thread (some sensors rely on the earthing of the housing to the block)
3)Shouldn't need a special socket to get the sender out, although it's in a pain in the a$$ spot to get at.

Re: Oil light on during idle after warmup
 

It'll be easier if you remove the oil filter first.

Re: Oil light on during idle after warmup
 

The motor is toast. Either rebuild it, replace it or just replace your oil pump to keep it going for a while longer, but the motor is worn internally.

Re: Oil light on during idle after warmup
 

yea i dont think its a bad oil pressure switch, i think its more towards engine worn internally.

Re: Oil light on during idle after warmup
 

Well, put a new oil sending unit in and switched to 10w40.

I couldn't replicate the oil light coming on even after turning the idle back down.
We'll see how it goes under normal driving.

FYI anyone else who is changing out the oil sending unit, a 22mm deep socket will be useful.

now for A/C and possible power steering....

Thanks,
Scott

Re: Oil light on during idle after warmup
 

The switch is cheap enough to do first. That might very well be your issue especially if it hasn't been replaced before. Check your oil level while the car is running.

Re: Oil light on during idle after warmup
 

Forgive the bumping an old thread but ffs, the W ain't for winter. It's for WEIGHT, the number at the end denotes the temperature range for that particular blend. Look in your manual at the graph that tells you to adjust according to your climate. Hondas in the 90's use 10W from the factory. The weight refers to the thickness of the oil. Example your Bearings clearances require 10W oil but your in climate with 45 degree Celsius weather you buy 10W40.

Running a thinner weight like 5W instead of 10W will cause the Bearings to wear sooner. Running thicker weight the engine will have to work harder to
push it around.

Next you will say 30W means 30 Winter oil and just out of curiosity where can I purchase some 10S40 as I need some summer oil.