No oil pressure this morning!!

Hey all,

Got in my 83 cabriolet GLi (1.8L) this morning to go to work. Engine started on the key but sounded a little lumpier than normal. cleared up within a few seconds.
Pulled out of my driveway and started driving down my street, when i looked down and my oil light was flashing rapidly at me . Gave it a small rev, no change. So quickly turned around and put it back on my driveway and turned it off.

Checked my oil. About half way up the stick.
Didn't see any oil pouring out of anywhere. sensors were still connected (Very recently replaced - within a week or two)

I replaced them as i was getting an occasionally flickering oil light when driving over about 65. The ones that were in there were noname brand sensors.
this didn't fix the issue. so suspected i just wasn't getting great flow to the head at higher RPMs. She's old, fair enough.

I have an oil pressure gauge i can hook upto the filter sensor port tonight when i am home from work. as well as top up the oil back to full.
just wondering what i need to be looking for? any common reasons on these to drop out oil pressure completely?

how is the oil pump driven? is it off the crank or off the dizzy shaft? Any way to spin the pump without the engine running?

Alex

The oil pump is driving off the intermediate shaft, the distributor is driven off the oil pump.

Verify that the connections on the senders are good, the flickering light is the right hand sensor can on the left side of the head.

If you used no no name senders that can be the issues as I had one that I bought cheap and it died about 2 days later.

The flickering bulb and buzzer is
low pressure at high rpm.  White sender on the oil filter flange

Flickering bulb is low oil pressure. which is one half of the can on the head.

Change your oil I used 10x40 or 20w50, and a good not generic, fram, or Bosch filter.

Use a mechanical gauge on the side of the head to verify that you have the 2.0 bar at 2000 rpm with hot oil at 80C. is the rule of thumb.  If you have that on your gauge then you don't have a bad pump but a bad sender or bad wire.


If you have pressure then it isn't your sender usually.

Causes Spun crank bearings, or journal clog.  Run an engine cleaner with the oil. for a bit then test again.  

You can replace the 32mm gear pump with a 36mm from a 2.0L but you will need longer bolts on the earlier cabbies and the oil pick up tube off your old pump as the ones on the 2.9L are longer and will not let the pan seal or bolt up correctly.

Thanks for that info that is really great!

for info i used:
https://www.heritagepartscentre.com/uk/028919081d-oil-pressure-switch-0-15-0-35-bar.html
on the side of the head

and: https://www.heritagepartscentre.com/uk/056919081e-oil-pressure-switch-white-1-pin-1-8-bar.html
on the filter housing.

Gotcha. No buzzer, so that is a good sign at least i suppose.
I will hook up my Gauge to the filter housing tonight first to make sure i have at least some pressure. then the head.
Any idea what reading these should have while could roughly? assuming higher than those hot readings.

Already changed my oil just before i swapped the sensors couple weeks ago. Used 20W50 and a Meyle filer.
oil still looks clean as a whistle. it's golden and nice on the dipstick.

Good to know about the replacement oil pump. assuming that is a bit of a plaster over the actual issues fix.
Is that a simple sump drop and few bolts. to swap the pump over?

Alex
 

If you have the center console gauges that are oil pressure bar, oil temprature and voltage, you should be using the 2 wire sender



I have seen the single sender on my diesel rabbit, that blinked the gauge at
low level oil, so topping it off may help.

Using a good quality filter can stop that as in Mann, Mahl, STP, Wix, Purelator gold, Mobil1, Genuine VW,  are known by me to not have the Blinky light from hades.

If you have the center gauges then the proper placement of the wires are essential as reversing then caused the lights to go sideways a bit.

my 90's cabbies were:


Don't have the early 79-84 Cabriolet / convertible wiring diagrams handy.
I had my Green Cabbie have issues with the sender ont he side of the head, and I relocated it to the Oil filter flange spare boss on the 90's
and used the boss plug in the side of the head.
Caveat, is I had mechanically fine pressures on the engine, but I don't know if the sender port was correct diameter even though the sender cost me about 60 USD.  So I moved the location of it to the flange, and I was running the 2.0L 36mm geared pump. This engine got a new to me crank Known good and new Main bearings, because of a Cam gear bolt issue which ruined the crank previous owners Mech put 110lbs of torque on a 12pt, 60ft/lbs bolt which drove it in to the bottom, and bent it.  The Machine shop I took it to had to use 400pst to remove the bolt which totall stripped the crank, (I needed to Salvage the front and rear seal carriers.

If you don't have the center gauges I would look into the wiring and grounds on your engine, and clocks.
If your Battery to Frame to engine/tranny cable is still oem or unshielded but a bad geren/brown color I would replace it out of hand and err on the side of caution.  I would also suggest adding a new ground wire to the main clister by splicing a wire in to the brown lead straight to the inner firewall on the connector side of the plug.

Only place I ever use a scotch-lok wire splice.






 

Nope, no gauges on my dash only the idiot light haha.

Great info, so cheers for that. I'll know how my pressures are later, hopefully they're not awful.

My dash has an oil temp display on the dash on one of the wiper stick button screens. I replaced the sensor as it was cheap and i was doing the oil pressure's as well. but it still just shows — as the temp. so not sure what's up with that. must be a wiring issue.

my clocks are a bit flakey, so adding a ground and doing the tape on the back of the connector trick is on my to do list.
I'll check the grounds on the engine with an Ohm meter later.

Update!

I've tested my oil pressure with a gauge.
Head pressure while cold. ~5 Bar
Head pressure while hot at 2K. Just under 3 Bar

Oil filter port while cold: ~5 bar
Oil filter port while hot at 2K. 3 Bar

Interestingly even while reading over 3-4 bar at 3.5K RPM on the head port, My oil light was flickering occasionally.

Rechecked at the Oil filter port at the same rpm and getting pretty much the same 3-4Bar. So i have some kind of odd wiring issue going on here.

Phew. That is a relief.

Grounds, Make sure there is a ground from the (as you look at it ) right rear valve cover over to the coil bracket.  If you have one great if you don't you want to add a flat braid or twisted wire insulated, and give it enough slack to account for engine torque.

Briano1234 said

Grounds, Make sure there is a ground from the (as you look at it ) right rear valve cover over to the coil bracket.  If you have one great if you don't you want to add a flat braid or twisted wire insulated, and give it enough slack to account for engine torque.

I have a ground going from the right front of my valve cover. to somewhere in the bay. not had time to look any deeper at this point. I'll set aside some time on a weekend to have a look at my wiring issues!