Oil Light

blu_jet_92

Veteran Member
Joined
May 13, 2010
Location
Deer Creek, IL
TDI
all of them
Anyone know what all can make the oil light pop on? 01 Jetta TDI... its momentarily poped on twice now and both times i immediately stopped and checked the dipstick... but the level is fine (even after sitting for 10-15 mins.....) any experience??
 

WestMass

Active member
Joined
Sep 6, 2006
Location
Deerfield, MA
TDI
Two Manual 2012 JSW's, one mine, one hers. 2002 Jetta GLS TDI 5spd- Sold
Obviously, this is an issue you need to identify right away. I don't have specific knowlege of this issue with the TDI, but here are my thoughts in general:

Did the light come on at idle or higher engine rpm? If at idle, it's possible the oil pump is worn to the point that it doesn't maintain the minimum pressure to keep the light from coming on, but provides sufficient pressure to keep the light off at higher rpm. It's possible the oil is diluted with fuel; how long since your last oil change? I had an '85 GTI with over 250k miles on it that the oil light began to flicker. Worn oil pump was the problem. If the light comes on at higher rpm than idle, I wouldn't drive it until you identify and fix the issue.
 

Joe_Meehan

Top Post Dawg
Joined
Sep 3, 2005
Location
Ohio USA
TDI
NB TDI, 2002.5, Silver
Let's start at the beginning.

When was the last time you checked the oil level?
When was the last time you changed the oil?
Are you sure you are using the correct oil?
How many miles on your TDI?
How many miles since you changed the oil?
 

Corsair

Veteran Member
Joined
Aug 17, 2003
Location
Auburn, New York
TDI
2002 Jetta GLS TDI 5M
Agree with the above, and to add some clarity (hope it's not redundant)...
=
The red oil light on the dash is NOT an indicator of oil level or quantity (ie. what you measure with the dipstick). The red oil light on the dash is an indicator that the engine oil pressure is below a minimum allowable level.
=
There is a pressure operated switch that detects oil pressure. The switch is typically located: If you open the hood and stand in front of the car as if you're checking the oil. Look at the oil filter housing, left (passenger) side of that, down low- there is an item screwed into the bottom area of the oil filter housing with a single wire attached to the end of it. That's the oil pressure switch.
As a side note, these cars typically have some "fudge" electronics built into the dash, such that even if low oil pressure is detected, the dash red light won't yell at you until the engine RPM is raised above some pre-chosen level, I think it's around 1500 to 1800 RPM. Then the red light comes on and typically a buzzer sounds, as well.
=
Getting back to the main topic- oil pressure is probably the most critical engine parameter in terms of needing attention "right now" if it happens to become a problem. Thus we come back to the questions asked above:
How many miles on the car ?
When was the last oil change ?
Are you sure the correct oil is in the engine?
Any running problems recently, that could have resulted in diesel fuel contaminating the oil ? (that could cause the oil to become thin and lose pressure)
=
Potential good news is that sometimes the oil pressure switch itself gets old and flakey, and the issue is caused by a defective switch and not an actual problem with engine oil pressure. Your description of the issue is perhaps the most frustrating, as it seems to be intermittent. Oil pressure issues are not something to take lightly. I would recommend as a test: (first, make sure the correct oil is in the engine and not diluted with a contaminant such as fuel) remove the oil pressure sender switch and install a mechanical oil pressure gauge there. Run the engine at idle and slightly above idle, make sure you have actual oil pressure. (Note that oil pressure varies with oil temperature; when first started, a cold engine will commonly have above 80PSI oil pressure at idle. When fully warm, the oil pressure at idle typically falls to 20 or less. Oil pressure rises with engine RPM. Specific numbers vary, but a fully warmed engine will typically have 40PSI or more at 2000 RPM. There are minimum acceptable specs in the service manual, sorry I don't have them handy right now. If the oil pressure checks out, replace the oil pressure sending switch. (you can get one from idparts.com, among others). They're not terribly expensive. I'm hoping you just have a flakey sending unit- it happens. Keep in mind- continuing to drive the car without diagnosis, if it does happen to be a real oil pressure problem, could end up with expensive engine damage.
=
Best of luck- please do post back what you find.
 
Last edited:

oilhammer

Certified Volkswagen Nut & Vendor
Joined
Dec 11, 2001
Location
outside St Louis, MO
TDI
There are just too many to list....
Most of the time it is actually a bad sender, and not a loss of oil pressure. However, only way to know for sure is to actually put a gauge on the engine. However, it is pretty quick and easy and inexpensive to just put a new sender in place.
 

jettawreck

Top Post Dawg
Joined
Aug 2, 2004
Location
Northern Minnesota-55744
TDI
2001 Jetta and 2003 Jetta
Had it happen a couple random times when I owned the 2000 Jetta. It's a chilling experience. :eek: Shut engine off-coast to side of road-check oil-wait and restart. Never found anything wrong and it only happened a couple times so the sensor never got replaced. Ran perfect up until I sold it and never did it for the last year or so I drove it. 5w-40 synthetic always. Odd.
 

blu_jet_92

Veteran Member
Joined
May 13, 2010
Location
Deer Creek, IL
TDI
all of them
do you know the part number??

Most of the time it is actually a bad sender, and not a loss of oil pressure. However, only way to know for sure is to actually put a gauge on the engine. However, it is pretty quick and easy and inexpensive to just put a new sender in place.
 

BobnOH

not-a-mechanic
Joined
May 29, 2004
Location
central Ohio
TDI
New Beetle 2003 manual
a little known fact - much of the oil pressure is created by the rod and crank bearings. The pump gets the oil to remote parts, esp. the top.
I hope it is the sender
 

Corsair

Veteran Member
Joined
Aug 17, 2003
Location
Auburn, New York
TDI
2002 Jetta GLS TDI 5M
yes. All it does is short the single wire to ground (the body of the sender).
When the sender sees pressure, it makes the ground connection.
When the sender sees no pressure, it opens. That way, if the wire happens to get broken, the light would come on. In other words, it's designed such that the sender must be making connection to tell the system everything is ok. Problem is... if it's an intermittent issue, the test can become moot.
 

blu_jet_92

Veteran Member
Joined
May 13, 2010
Location
Deer Creek, IL
TDI
all of them
exactly... this problem is extremely intermittent... i'd rather just replace it.

yes. All it does is short the single wire to ground (the body of the sender).
When the sender sees pressure, it makes the ground connection.
When the sender sees no pressure, it opens. That way, if the wire happens to get broken, the light would come on. In other words, it's designed such that the sender must be making connection to tell the system everything is ok. Problem is... if it's an intermittent issue, the test can become moot.
 

Becca

New member
Joined
Dec 5, 2010
Location
St. Leonard, MD
TDI
Golf TDI '03
oil pressure switch - broke wire, how to fix?

In the course of some other minor repairs the wire to my oil pressure switch was accidentally severed where the wire enters the black plastic housing (which I think holds the actual switch). We have the connector (p/n 1J0973081) but there's no 'tail' of the wire coming out. We need to figure out a way to re-attach the wire to the connector. Does anyone know where to buy a replacement of this that has wire already attached? Anything we find online looks like it's just the connector.

this is the part that we have: http://www.alibaba.com/product-free/123446121/1J0973081_1_Way_Sealed_Female_Connector.html



"There is a pressure operated switch that detects oil pressure. The switch is typically located: If you open the hood and stand in front of the car as if you're checking the oil. Look at the oil filter housing, left (passenger) side of that, down low- there is an item screwed into the bottom area of the oil filter housing with a single wire attached to the end of it. That's the oil pressure switch."
 

turbocharged798

Veteran Member
Joined
May 21, 2009
Location
Ellenville, NY
TDI
99.5 black ALH Jetta;09 Gasser Jetta
You will need vw repair wire. I am guessing that it would be a 000 979 131 repair wire and a 357 972 740F seal. 1J0 973 701A appears to be the only single terminal D shaped housing though. The above mentioned repair wire and seal should fit the housing. You may want to double check part numbers on ETKA.

Splice remaining wire to repair wire with a heat shrink crimp butt connector.
 

JettaTDIGuy

Veteran Member
Joined
Mar 2, 2001
Location
Phoenix, AZ USA
Just wanted to pop in and thank those who helped - I just got the oil light and freaked out. Checked oil level, good, no leaking going on, jumped on here.

Of course, when this was happening, it was at night (dark) and nothing looked out of the ordinary. After my oil pressure sensor was delivered, I went to install it, and found that the oil filter cap was very loose. :eek:

Went ahead and replaced the AZAutoHaus sourced sensor, anyway, but I'm thinking the old sensor was just fine.

Just another thing to check for, if someone else runs into this same problem!
 

jettawreck

Top Post Dawg
Joined
Aug 2, 2004
Location
Northern Minnesota-55744
TDI
2001 Jetta and 2003 Jetta
Just wanted to pop in and thank those who helped - I just got the oil light and freaked out. Checked oil level, good, no leaking going on, jumped on here.

Of course, when this was happening, it was at night (dark) and nothing looked out of the ordinary. After my oil pressure sensor was delivered, I went to install it, and found that the oil filter cap was very loose. :eek:

Went ahead and replaced the AZAutoHaus sourced sensor, anyway, but I'm thinking the old sensor was just fine.

Just another thing to check for, if someone else runs into this same problem!
Unless the filter canister was leaking oil, I don't think the loose cap would have anything to do with lack of pressure indicator light coming on.
 

vwdieseling

Veteran Member
Joined
Apr 5, 2012
Location
Lima Ohio
TDI
Beetle, more bugs
Did you check the oil cooler gasket. These get hard and start leaking, they blow out after ten years. When they blow out you will lose your oil and pressure also all your oil will end up somewhere down the highway. Some times they go at strange times. (Please research this I am not kidding.) I am a Volkswagen freak and this is one of our big peaves. We consider it normal maintanance to change these gaskets. Easy to replace cost is $3.95 or so. Just replace it, its worth it. Sometimes the gaskets crack and leak intermediatly could cause a sudden drop in oil pressure the cooler is just below sensor on filter. There is a jam nut that holds the cooler on, remove this and lower cooler with hoses attached. The gasket is between oil filter and cooler. Wait on TDI there is a square like nut that protudes down that holds the cooler on. On the gassers its a jam nut. There will be oil around the top of cooler if bad. Its a round gasket with little alighnment tabs these are the improved ones. Just a tip if your working in that area.
 
Last edited:

GT TDI Golf

Well-known member
Joined
Nov 3, 2006
Location
Birmingham/Auburn, AL
TDI
2001 Golf TDI
Does anyone know what oil pressure TDI's should see? My buddies TDI just started flashing the oil light. It has 190k miles '03 Golf. Warm idle is around 12psi he said. He uses the correct oil. I can't find my Bentley manual so I was hoping someone would know it or have theirs handy. Any other ideas? Thanks!
 

ajrn

Veteran Member
Joined
Oct 1, 2005
Location
Toledo, Ohio
TDI
'97 Passat, '98 Beetle
Just restarted my 97 passat 1z, with whitbread ahu cam'd rebuilt heads and dbw rebuilt injectors.. it's been a saga.. Some "rebuild" some life events stuff..


The rebuild was all new parts, mostly impex/idparts. I had the oil pan off, and replaced the oil pump, "while I was there..."

I primed the injectors, and it started, on the first crank, that all the injectors were "closed.." it idled fine.. NO ODD NOISES.

BUT.

The oil pressure light is FLASHING. LIKE A TURN SIGNAL

Didn't blip the accelerator, it idled probably 2 minutes max. It's probably valvoline 'diesel' oil, or rotella synth. Oil on the dipstick, new filter...

It's been awhile since I've had the car on the road.. When I was hand cranking the engine to verify timing belt, I was getting oil up into the head..


I've burned a ton of cash/time on this car/engine.. Don't want to make a n00b mistake, and set myself back..



Direction, please? I'm looking for a mechanical oil pressure gauge, after supper, I know I've got one here, somewhere!

Thanks in advance, I've never been sent the wrong way here!
 

BobnOH

not-a-mechanic
Joined
May 29, 2004
Location
central Ohio
TDI
New Beetle 2003 manual
Could be bad rod/crank bearings.
But first rule out the oil pressure sensor, etc. You're oil pump must be working if it kicks oil up to the head.
 

ajrn

Veteran Member
Joined
Oct 1, 2005
Location
Toledo, Ohio
TDI
'97 Passat, '98 Beetle
Quote: "Your oil pump must be working if it kicks oil up to the head."

Pretty much what I thought..

I'm going to put a mech gauge on- and see that it tells me.. Just wanted to make sure everything else made sense..

There should be no reason for crank issues-- the car was running fine, up to the moment it wasn't.. LOL
 

ajrn

Veteran Member
Joined
Oct 1, 2005
Location
Toledo, Ohio
TDI
'97 Passat, '98 Beetle
Hold on-- there are two oil pressure transducers??

**from id parts**

http://www.idparts.com/catalog/product_info.php?products_id=3294

OE Part Number: 068919081A

OEM VW oil Pressure switch for AHU or 1Z engine code in A3 chassis Jetta or B4 chassis Passat.
This sensor is located on the oil filter housing and measures oil pressure above 2000 RPM. Failure of this sensor will cause the oil pressure light and buzzer stay on.


and



http://www.idparts.com/catalog/product_info.php?products_id=3241


OE Part Number: 028919081H
Manufacturer's Part Number: 056919081C New oil pressure switch in cylinder head for A3 and B4 models. It is rated for .25 bar.


.25 bar is like 3-4 PSI.. I'm assuming this is a "DUDE! You've killed it, light.." So the first one would be the "issue.."

I never blipped it.. I'm going to try taking it to 2000 rpm..



...but maybe the mech gauge, first..
 

IndigoBlueWagon

TDIClub Enthusiast, Principal IDParts, Vendor , w/
Joined
Aug 16, 2004
Location
South of Boston
TDI
'97 Passat, '99.5 Golf, '02 Jetta Wagon, '15 GSW

ajrn

Veteran Member
Joined
Oct 1, 2005
Location
Toledo, Ohio
TDI
'97 Passat, '98 Beetle
I'd bought the oil pump from Bora's..

They're sending me the correct one, and only asked that I return this one-- so they can figure out what happened..

My used one, that was just fine, is pumping oil just fine in a repowered vw turbodiesel 1.6 pickup..

...I may be re-thinking the-- ****, I'm here, I might as well replace it, program!
 

tristan21

Well-known member
Joined
Feb 13, 2010
Location
Marshfield, MO
TDI
01 Jetta 02 Jetta Wagon (dead/rolled)
Did you check the oil cooler gasket. These get hard and start leaking, they blow out after ten years. When they blow out you will lose your oil and pressure also all your oil will end up somewhere down the highway. Some times they go at strange times. (Please research this I am not kidding.) I am a Volkswagen freak and this is one of our big peaves. We consider it normal maintanance to change these gaskets. Easy to replace cost is $3.95 or so. Just replace it, its worth it. Sometimes the gaskets crack and leak intermediatly could cause a sudden drop in oil pressure the cooler is just below sensor on filter. There is a jam nut that holds the cooler on, remove this and lower cooler with hoses attached. The gasket is between oil filter and cooler. Wait on TDI there is a square like nut that protudes down that holds the cooler on. On the gassers its a jam nut. There will be oil around the top of cooler if bad. Its a round gasket with little alighnment tabs these are the improved ones. Just a tip if your working in that area.
First I have heard of this. I guess if mines not leaking it is still in good shape? I assume any loss of pressure due to the oil cooler gasket would be obvious?
 
Top