[vwzx]

What would cause my oil light to come on when the engine has been running for a while and is warm? It only happens when the car is sitting at a light. I have enought oil in it. Should I switch to a thicker oil? I live in San Diego so I could run 20W50 in the engine.

 

[Mk1Racer]

Re: oil light ? (vwzx)

The light comes on because the oil pressure has dropped below what the sensor is activated at. Has nothing (sort of) to do w/ having enough oil in the car. Since the car is hot, the oil is hot as well. Oil viscosity goes down w/ temp. Since the car is at idle, the oil pump is moving at the slowest rate while the engine is running. That means that it's generating the least amount of pressure when the engine is running.
Could be a couple of things. You could be running to low a viscosity of oil for the climate conditions that you're in (e.g. 5W30 in Az. in the summer time), or your oil pump may be on its way out (I'm guessing this one). My car runs 130 - 135 deg. C on the oil temp when the car is hot, and I have 1.5 - 2.0 bar (~25 - 35 psi) of oil pressure at idle and I run 10W40 oil in the car.
If you're running the wrong viscosity oil for your climate conditions, putting the correct viscosity oil in should fix the problem. And if the oil pump's getting worn, switching to 20W50 will be a temp. fix, but won't address the real problem of a worn oil pump.

 

[retrohasen]

Re: oil light ? (vwzx)

Great info, but you might try replacing the oil sensors first. They are relatively inexpensive. My oil light went on last summer while driving on the interstate in 107 degree heat. My friend suggested that i replace both sensors and that solved the problem. I would change the oil first.

 

[xjronx]

Re: oil light ? (millerwj)

i have a similar problem, my oil light comes on at like 2000 rpms and i pressure checked the oil sender hole, it had pressure so i swapped the sender but the light still comes on. is there more than one sensor on an 84 gti? i replaced the one on the right side of the head.


[Modified by xjronx, 9:18 PM 2-11-2002]

 

[retrohasen]

Re: oil light ? (xjronx)

quote:[HR][/HR] is there more than one sensor on an 84 gti? i replaced the one on the right side of the head.
[Modified by xjronx, 9:18 PM 2-11-2002][HR][/HR]​

There is also one on top of the oil filter housing.

 

[Mk1Racer]

Re: oil light ? (retrohasen)

quote:[HR][/HR] is there more than one sensor on an 84 gti? i replaced the one on the right side of the head.
[Modified by xjronx, 9:18 PM 2-11-2002]
There is also one on top of the oil filter housing. [HR][/HR]​

The one on the side of the head is for the light, the one on top of the filter housing (near the temp sender) is for the warning buzzer.

 

[The Nothing]

Re: oil light ? (xjronx)

quote:[HR][/HR]i have a similar problem, my oil light comes on at like 2000 rpms and i pressure checked the oil sender hole, it had pressure so i swapped the sender [HR][/HR]​

how much pressue did you have? when you're over 2k you should have over ~22 psi or 1.5 bars - MINIMUM... If you don't have this you're looking into replacing the oil pump


[Modified by PDX Cabby, 7:45 PM 2-11-2002]

 

[vwzx]

Re: oil light ? (millerwj)

I payed a bit more attention to my problem. I also have a dipping idle that goes from 1000rpm to about 600-700 rpm. When the car is warm and when the idle dips the light will flash a few times. As soon as the idle jumps up to 800-1000 the light goes off. I am also at about .5-.75 bars at idle. Is my oil pump going out? Is that costly/complicated to fix?
The oil sending unit is where exactly?
Thanks.

 

[maximus_manx]

Re: oil light ? (vwzx)

Run an OE oil filter(Mann for example), and at least 15w40 or 20w50 oil. My 200,000 16V GLI is quiet & happy this way.

 

[xjronx]

Re: oil light ? (maximus_manx)

yeah both sendersw seem to be fine, and i seemed to have good pressure, 49 psi( but thats a cheapo gauge so iassume its wrong but it showed pressure) . both the light and buzzer come on at 2000 rpms but sometimes the buzzer goes off a litle higher. what do i trace the wire to from the senders? is there a relay or how do the senders work, do they open or close a electric circuit at specified pressure( ex letting the electronice ground to the engine ). how could i dissable the buzzer and light untill i solve this problem. i gonna check the pressure with a much better gauge today but i'm sure that not the problem.

 

[Mk1Racer]

Re: oil light ? (xjronx)

quote:[HR][/HR]yeah both sendersw seem to be fine, and i seemed to have good pressure, 49 psi( but thats a cheapo gauge so iassume its wrong but it showed pressure) . both the light and buzzer come on at 2000 rpms but sometimes the buzzer goes off a litle higher. what do i trace the wire to from the senders? is there a relay or how do the senders work, do they open or close a electric circuit at specified pressure( ex letting the electronice ground to the engine ). how could i dissable the buzzer and light untill i solve this problem. i gonna check the pressure with a much better gauge today but i'm sure that not the problem.[HR][/HR]​

I doubt that both of the senders are bad. If this is what you've got going on, I'd get a reliable gauge and check it ASAP. You could have a bad oil pump, and you don't want to ignore that!

 

[stevelangford]

Re: oil light ? (millerwj)

There is a little circuit board that is in the dashboard and when it goes bad it makes the light come on under 2k rpm, if this happens the easiest way is to install a real oil pressure gauge or get the circuit board fix or replaced, don't ask me more because it is a mistery for me how to find the board or hoe to replace, maybe someone here knows.