oil light and buzzer

[pushkick]

just put a new head gasket and oil pump switch(the one buy the water pump). put 10w-40 oil and filter (mann). drove for awhile then after a week the oil light and buzzer started going off. only after the engine is warmed up and it seems to go off only when accelerating or above 2000 rpm. now the oil pressure gauge indicates around 6-10 psi when at idle, and at 2000rpm around 16-20psi, and at 3000 rpm 22-27psi. (hard to read gauge). when i first start the engine the gauge reads anywhere from 50-60 psi until the engine is warmed up. tested the switch for correct operation in the garage and seem to work correctly (unplugged when above 2000 rpm and it went off). any ideas on what the problem might be would be greatly appreciated.
_________________
i see said the blind man to his deaf dog
i am going to quit smoking and drinking and die a healthy man. gotta laugh
there is no deed to the planet earth
1990 vw automatic camper

[bluebus86]

Your pressures are on the low side, 22 psi at 3000 rpm warmed up is below the wear limit. Id get the pressures confirmed. Do not drive with the buzzer sounding until you figure out what is wrong.

A....Either your buzzer is wrong, or it is right and if so you have too low pressure.


B.....Either your gauge is wrong, or it is right and if so you have too low pressure

HOPEfully your buzzer and gauge are both wrong and you really have great pressure (45 spi at 3000 fully warmed up).

However I would not keep driving on HOPE.

You got two independent warning systems (gauge and buzzer) telling you that your oil pressure is too low. Keep driving on low pressure and the engine will self destruct, and maybe not be repairable.

Causes of low oil presure are:
1. Rich running, and short cold drives lead to build up of gasoline in the oil, making it thin, low pressure, oil may smell like gasoline, if so change the oil and see if it improves, then fix cause of the richness.

2. Worn bearings, high miles. you know what that means.

3. Worn out oil pump, incorrectly installed oil pump cover/gasket. remove and check clearances, use thin gasket on cover

4. Too thin an oil, (you might consider 20w-50 oil on a tired engine, but that wont fix a worn engine, only help reduce further wear) 10w-40 might be too thin.

5. Engine getting too hot, check your temperature, make sure your water temp gauge is acurate and not reading too high, if you got an oil temp gauge, confirm it reads right in boiling water. It only takes an extra 30-50 F or so too hot of an oil temp to dangerously drop oil pressure.


You did some work on the head gasket. what did you do that might have changed something? The motor's bearings or oil pump didn't suddenly wear, you didn't touch them, didn't open the oil pump cover, nor crack the case.

so could you have a gauge error? (maybe a common engine ground strap is bad, so all your gauge voltages are wrong????)

Could something with the head work have caused the motor to run hotter? Higher compression now? , more friction? water passages blocked at head? More heat will lower oil pressure. Is the coolant fully bled of all air??? improperly bled coolant can form an air pocket that can cause over-heating , hence thin oil /low pressure confirm properly coolant bleeding, if over heat suspected


you had to remove part of the injection system, so could it be that the injection is now running rich? (disturbed wires, damaged injector (did one get dropped?) Oxygen sensor wire, Temp sensor wires on thermostat housing, etc...) does the engine oil on the dip stick smell anything like gasoline?

best of luck, just dont drive till you got it figured out.

[insyncro]

Try using 20/50 weight oil.

[0to60in6min]

follow the wires of those 2 oil pressure sensors. They come up into a white plastic connector before going in the harness (driver side of engine bay).

Make sure that white connector is is well connected to the one from the harness, from outside it seems connected but it miss the true connection.

[pioneer1]

here are a few more items regarding oil pressure from a sponsor
http://www.van-cafe.com/home/van/page_15
_________________
"Always waiting for tomorrow ruined everything"

'85 Porsche 911 Targa

'76 Westfalia project

[insyncro]

[pushkick]

forgot to mention i put a new oil pressure valve spring in when i did the head gasket. the old spring was compressed a little and my oil pressure had been on the low side. this is a factory rebuilt engine from canada and has about 70,000 miles on it. compression on cylinders all read around 125 psi. the reason i did a head gasket replacement was a coolant leak and when i did a pressure test on cyclind 4 there was air leaking into the coolant system (could see the bubbles in the coolant reservoir. havent noticed any over heating and the coolant temp seems to be working properly. i changed the oil and filter when i changed the head gasket.
_________________
i see said the blind man to his deaf dog
i am going to quit smoking and drinking and die a healthy man. gotta laugh
there is no deed to the planet earth
1990 vw automatic camper

[pushkick]

well i went to 10w-40 oil instead of the 10w-30 seems to help somewhat. the problem seems to be after engine is warm, shut it off then restart and when i go for a drive around 4 miles ( @55mph) then stop and accelerate the buzzer and light go off, let off the gas and light and buzzer goes off. this may happen twice. if i let is sit in driveway in park and rev engine no light or buzzer.
_________________
i see said the blind man to his deaf dog
i am going to quit smoking and drinking and die a healthy man. gotta laugh
there is no deed to the planet earth
1990 vw automatic camper

[pushkick]

there seems to be several issue here. seems that only when the rpm is over 2000 the buzzer will go off but the oil pressure from the gauge is between 20-30 psi. this only happens when the engine is warmed up. i looked at the voltages on the pressure sensor by the pulleys and below 2000rpm the voltage was 2-4 vdc but when i rev the engine the voltage seems to bounce between .5-1vdc and 12 vdc when the engne is off but ignition is on. what is the correct voltage i should see?
_________________
i see said the blind man to his deaf dog
i am going to quit smoking and drinking and die a healthy man. gotta laugh
there is no deed to the planet earth
1990 vw automatic camper

[crazyvwvanman]

The oil alarm circuit board watches tach pulses to decide which pressure switch to react to. It ignores the higher pressure switch unless it sees tach pulses above 2000 rpm. The buzzer sounds only for the higher pressure switch warning. The oil warning led blinks for both switches.

Some of the Bentley diagrams and many parts catalogs list the wrong switch for the high pressure position. The correct high pressure switch is .9 bar. The wrong switch is 1.8 bar, used on other VWs. Has anyone changed the switch out? Since your pressure reading look ok my guess is either the switch is going bad or the wrong switch is in there.

These switches are not very precise devices and the numbers below are only approximate.

The low pressure switch is .3 bar = 4 psi
The high pressure switch is .9 bar = 13 psi

Wrong high pressure switch is 1.8 bar = 26 psi, used on inline VW engines.

I would replace the switch.

Mark

[Phishman068]

What's involved in replacing the .9 bar switch?
I heard pulleys have to come out and what not, but I can't seem to believe it can't be done easier than that.....

[AtlasShrugged]

Yes, the switch behind the crank pulley is a tough one. It requires a deep socket to reach it. The cheap solution is a plumbers socket. Most hardware stores and Home Depot or Lowes has them.

Reach down and disconnect the sender wire. Find the right size socket from your plumbers kit and remove the sender.

Go ahead and get a .9 bar oil switch sender and replace the one you have installed. It is a cheap part. Try and use a German switch if you can. The China parts are troublesome. NAPA has a good one. Part # ATM 068919081A..$9 made in Germany.

There is a sender holding lug back behind the switch in there too. Try not and remove it too. It can happen if the plumbers wrench is deep on the switch when you turn.

[dhaavers]

Keep your pulleys on...

I just did this (.9 bar switch) end of the summer - it's fiddly, but doable.
I used a standard 24mm socket & lots of finger wiggling.

My post: http://www.thesamba.com/vw/forum/viewtopic.php?t=478217
...and thanks again to AtlasShrugged for good help when I needed it!
_________________
86 White Wolfsburg Westy Weekender
"The WonderVan"
<EDITED TO PROTECT INNOCENT PIXELS>

[kevtherev]

ditto
I just pulled the belt off

[pushkick]

yep it is the new switch i put in i got one from vc and when i took
it out and tested it went off at 19psi. so i ordered one from BD i will
see how this works. they say that the one they sell is .9 bar.
thanks for the help.
_________________
i see said the blind man to his deaf dog
i am going to quit smoking and drinking and die a healthy man. gotta laugh
there is no deed to the planet earth
1990 vw automatic camper

[pushkick]

i havent found a oil pressure switch from bd or vc that works at the .9 bar or 13 psi. both ones i have ordered have triggered at 17.5 -19 psi. has anyone else had this problem? where do you get your oil pressure switch. this is the switch by the water pump pulley on a 2.1L 1990 vanagon.
_________________
i see said the blind man to his deaf dog
i am going to quit smoking and drinking and die a healthy man. gotta laugh
there is no deed to the planet earth
1990 vw automatic camper

[dhaavers]

From my thread this summer:

[devesvws]

[86 Westy]

I'm having a similar issue. Changing oil does seem to help for a while. I'm also having running issues at hwy speeds and I was thinking it could be caused by over fueling and gas thinning out the oil so its good to know that could be the culprit. My buzzer and light only go off when i'm below 3,000 rpm and only after it's warmed up (about 10 to 20 minutes of hwy driving). If I downshift or accelerate, the buzzer/light shuts off almost instantly at 3,000 rpm. That being said, should I be changing the pressure sensor on the side between the push rods or is this more likely a "computer" problem because it's happening at 3,000 rpm instead of 2,000? Also, if the buzzer/light comes on when I'm slowing down and it drops below 3000 rpm, I downshift, it pops over 3000 rpm, shuts up and usually doesn't come back on again until i'm back up to speed for a while then slow down again. My mechanic says not to worry because if it was a true oil pressure problem, it would be destroyed by now. I recently bought the van (first Vanagon) and put about 350 miles on it so far. I plan on taking it on a 3,500 mile trip in just two weeks so i'm a bit worried. I'm dealing with the running issue in a separate thread and I think I have it narrowed down. Thanks for all the help.

[SteelB12]

Can anyone point me in the right direction to replace the oil LED? I have neither the LED nor the buzzer and would like to replace both, but want to start with the LED.
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1987 Westy