New member needing help with unique situation

Hi All,

I'm the proud owner of a 2005 TDI Golf that I bought a little over a month ago and in trying to track down the reason my oil light keeps coming on/going off, I finally got my hands on the service records from the dealer and got a bit of a surprise. It turns out that the engine was replaced a little over a year ago (I spoke with someone at the shop today and he was good enough to answer a couple of questions for me) because of a problem with the high-pressure fuel pump. Before the replacement was put in, it had a timing belt/water pump replaced, new glow plugs, the (nearly new) high-pressure fuel pump (that had been ordered too late to save the old engine) and within the last year, a new oil pump put in. It also had the auto transmission rebuilt last March due to a reverse gear problem.

I LOVE the car and it's actually the 13th VW I've owned (the 3rd diesel but BY FAR the most sophisticated - the last one was an '87 Jetta) on all of which I've done most of the maintenance myself. Now that I'm chasing down the oil light problem (I've replaced the high-pressure sensor on the oil filter base) I'm unsure what path to follow in that I don't know if the engine that they replaced the original with is a PD. Since the oil pump was replaced in March of this year, my next course of action is going to be to make sure the pressure is OK with a gauge and if everything looks OK (by the way, I couldn't find a pressure chart for PSI/BAR per RPM so if anyone has a source I'd appreciate it!) but I want to make sure I've got the engine model/type figured out before I do much else.

Any thoughts would be hugely appreciated!

Mahalo,
Sharkey

It is certainly a "unique situation", because your '05 has a PD motor, which does not have a "high pressure fuel pump". The dealer is feeding you a bunch of B.S.

That was one of my questions - whether or not the engine they put in it is ACTUALLY a PD or not. It could only be a little older/newer and it wouldn't be a PD from what I can tell, correct? I have some experience with the older diesels but I can't tell if this one's actually a PD by looking at it. Are there any obvious identifiers? I'm usually pretty good with the obvious...

Pictures of said engine would help us tell you.

Look on the top of the timing belt cover or maybe the emissions sticker. A Pumpe Duse (PD) will have an engine code of either BEW or BRM.

A PD engine has an in tank lift pump, an intermediate pressure Tandum pump driven by the cam and the injectors serve as high pressure pumps.

Failure of any of those would not take out the engine except that the Tandum pump can leak fuel into the oil system and dilute the oil. The tech you talked to was probably just making stuff up on the fly.

A leaking Tandum pump will thin out your oil and cause your oil level to rise. If the oil gets thin enough, it could cause low oil pressure. Best thing to do is to stop driving the car and temporarily plumb in a direct reading gauge.

You need to find out if you actually have low oil pressure or an indicating problem. You need to stop driving the car, because if the oil pressure is actually low, you are destroying your engine.

Awesome, thanks O.R. - that's exactly the info I was hoping for! As you suggested, I checked the timing belt cover and it IS a PD after all so now I have a starting point.

As for what the tech told me, he said something about the P.O. Ignoring the check engine light for a while before bringing it in and that the pump malfunction basically did what you said it would. I guess it went on for long enough that it messed things up enough to need to swap out the engine - if that we're the case it sounds like it may not be something he told me to get off the phone. I'm going to call back today to see what else I can find out.

Thanks again, I really appreciate the assistance!!!

EDIT:
Has anyone else had any difficulty finding an oil pressure test gauge at a local parts store? I've been to 4 places without any luck.

I would start by checking the wiring if the pressure warning comes on for no apparent reason (I would expect it to do this most often while accelerating). The oil pressure switch is a simple normally open switch. You can do one of two things to diagnose:

1. Connect an ohmmeter with a beeper that can be set to beep when the circuit is open between ground and the pressure switch. The tester should never beep once the engine is running.

2. Test the resistance between pin 10 on the blue instrument panel connector and the pressure switch wire end. It should be very near zero (about 0.5 ohms). Have a helper wiggle the harness and engine or use a min/max function. Look for fluctuations in resistance.

If using a pressure gauge, oil pressure should be > 0.55 bar at idle, and > 2.0 bar at 2000 rpm (at operating temperature), and < 7.0 bar at all times.

Apparently I can't upload photos so I'm going to have to beg for help in the most creative way possible....

I couldn't find an oil tester at any of the local stores (I just moved and don't have local knowledge yet) but I did find a psi/bar gauge made for some sort of Hitachi power tool that had matching threads to the high pressure oil sensor at the base of the filter. When I put it in, the psi went to about 10 at idle (the needle was jumping around a bit), went up to about 20 or so at 2k rpm, 30@3k, but then settled sort of in the 25psi range as the car sat at 3000 rpm's for a bit. On the one hand this sounds a bit low but I have no idea if the gauge I got is right or not or can even be used for this as it was designed for something else. On the other hand, the 10psi/1000rpm rule-of-thumb seems to say I'm generally in the range but it's the drop I'm worried about. I was told to check the low pressure sensor on the block too but I'm not 100% sure where it is (I think I located it - if it's held on by a single star-bolt that's a ***** to get to I'm pretty sure it's what I think it is). I also discovered a pretty decent oil drip coming from behind the crank pulley just above the oil pan. Would that be what's throwing things off?

Engine is most likely a PD. A common rail engine would not go into your car easily at all. And the pump they're referring to is probably the tandem pump at the end of the camshaft, which is a vacuum/fuel pump (hence the name tandem). If it leaks it'll add fuel under the valve cover, keep the camshaft from getting lubricated, and kill the cam and lifters. That would require a new head (maybe) but not an engine. Maybe something else happened, too.

At any rate, the oil pressure numbers you report do seem low, even when considering VWs tend to run low oil pressure at idle. I honestly don't know why, unless someting's wrong with the oil pump or the pickup for the pump. You could have someone drop the oil pan and look at it and perhaps replace the pump. I don't think the leak is going to make a difference unless your oil level is very low. And I'm pretty sure the oil pressure sensor is on the oil filter canister on your car.

Take it to Harv in Whittier.http://vwtdionly.com/default.asp?newused=5

25psi is dangerously low at 3k RPM under load. 10psi @ idle is in old-tech Detroit Diesel territory, not modern engine range, although it's less likely to do damage at idle and as id noted VWs have a tendency to run lower oil pressure than most modern engines at idle speed.

You may have a relatively severe oil dilution problem -- the easiest way to check for it (assuming the oil doesn't smell like fuel) is to change the oil and see if the pressure comes back up. If not you need to figure out what's going on as if that gauge is right you got a problem that needs immediate resolution.

The other likely possibilities are a stuck oil pressure regulator valve, a bad oil pump/clogged pickup or a severe problem with clearances somewhere in the engine. The latter is very un-good but absent other symptoms relatively unlikely. Gas engine Audis/VWs from that rough time frame are known for sludging up the oil pickup if improper oil is used (I've seen a few of them) but a PD engine with improper oil in it would almost-certainly destroy the cam first.

IMHO YOU SHOULD NOT DRIVE THE CAR UNTIL YOU FIGURE THIS OUT. Main and rod bearing metal-to-metal contact, which is very possible with low oil pressure, especially under load, can lead to catastrophic engine failure.

10 psi is not far off the mark, with just over 12 being 0.85 bar (the upper limit of the 0.55-0.85 bar brown oil pressure switch). It should be at least 30 PSI at 2k rpm, however. Before panicking, I would use a second gauge and make sure it agrees with the first. If it does, it's time to plastigauge the main (crankshaft) bearings.

The ALH at least, from what I understand, does not throw a low oil pressure warning at low RPM (intentionally); it is NOT just a switch to the light.

Genesis said:

The ALH at least, from what I understand, does not throw a low oil pressure warning at low RPM (intentionally); it is NOT just a switch to the light.

Click to expand...

Your understanding is partially correct, however it appears you're conflating the fact that the switch is a simple device with the idea that it's connected to a lamp.

The panel monitors the signal, which is in the 'good' state at 0.55-0.85 bar or more. It is correct that the cluster will disregard an open switch with the engine turning for a short time, but it will set an alarm if too much time passes (e.g., cranking too long without starting). All other times, the alarm will occur very quickly when the switch opens.

Hi All,

First off, THANK YOU for all the feedback, I really appreciate the help.

I went ahead and ordered a proper oil pressure tester so hopefully I'll have the answer to that question sooner than later. My Dad's an old hot rodder (who now drives a Passat TDI) and when I called him to ask his advice, I knew before I even got the words out of my mouth that my $3 air-pressure gauge setup thing was going to be shot down immediately. It's too important to know to rely on something that dodgy.

I also started experimenting with the RPMs to see if I could get the oil light to consistently go on and what I found was that it seems to start beeping when the revs drop below 2k. The car has an automatic/tiptronic transmission and when accelerating from a stop it usually doesn't come on until the car's at speed and running at about 1800-2000 RPM. In fact, I can even get it to shut off if I keep it in a low gear and run at 2700-3000.

My limited knowledge base would leave me to believe that either A) the higher revs are building up the pressure and that's what's making the light go off or B) The low pressure sensor isn't working properly. I'm sure there's answers C-Z but I guess I won't know until I sort out the actually running pressure, right?

Do not drive the car with the alarm going dude.

If it's real and not a bad sensor you've either lunched the engine or you're going to.

Ok, the pressure tester is on it's way but in the meantime I want to check out the oil level/low pressure sensor. Can anyone tell me where it is?

There is only one switch, on the filter housing (brown). You don't have a level/temperature probe.

Guess that explains why I've been having trouble finding it.

Do the common rail engines have them? I was told more than once I had to check the low pressure sensor.

You have a pressure sensor, but not a level or temp sensor.

I changed out the one that jcrews mentioned but thought there was another, low pressure one, based on the reading I've done but apparently not?

Here's the latest, could really use some more help:

I got the pressure gauge and when hooking it up discovered that I needed the elbow attachment to get the hose from the gauge on. I managed to get it on and fired up the engine and it sat idling (hot, I had brought it out and waited until it started beeping) and the pressure was pretty low ~10psi. When I got in the car and revved it up to 2K the pressure went up but not by much - maybe 20-22psi. I went up to 3000 RPM and the pressure didn't change much at all so I shut the whole thing down. When I looked under the hood, I discovered that the elbow fitting must have been leaking because there was a pretty big pool of oil on the tarp I laid out. So basically, I have no idea if it was blowing out the oil when the pressure went up which meant no increase or if it was just leaking out at 20psi. Regardless, I'm pretty frustrated.

I was also surprised to find that the oil level didn't drop given the amount of oil that accumulated on the floor. In fact, it looked like it went UP if anything. It doesn't smell like fuel and I'm not burning oil....I'm out of ideas and feeling defeated.

Anyone have any ideas?

I have an oil pressure gauge in my '01 TDI. Here are the numbers I typically see. I have an ALH motor, not a BEW but I'll guess the engines have similar oil pressure. I've had the gauge in for 6 years and about 300K miles and the numbers have been consistent over that time.

Cold start: pegs gauge (80+ psi) at idle. A cold start in warm weather (60-70F) may result in 60psi at idle.

Warm idle: low 20's, probably around 22-23 up to 30, depending on the oil temp.

At 2000 rpm, warm: 40-50, again depending on exact oil temp

Running 2400-2600 rpm, 70-80mph on freeway: maybe up to 60

The Bentley manual only shows one oil pressure spec, at 2000 rpms. ALH motors: 36psi, BEW: 29psi.

I recently replaced the oil pump due to low readings. At idle the needle was just to the left of the 20 mark, probably 18psi or so. At 2000 rpms, it was 30 which was below spec. Swapped in a new pump and readings were back to normal. I have 470K miles, so I got my money's worth out of the original pump.

These readings are all on Rotellta T6 5w-40 oil. Other oil weights would affect oil pressure readings, of course.

Not sure why you would need an angle adapter?

Unscrew the oil pressure sender, and screw test hose in place.

Not uncommon for oil pressure sensor to be bad, but you must confirm by testing with quality mechanical gauge.

Sounds like you need a TDIClub trusted mechanic to look at this.

If you can confirm your pressure is low, prepare to spend some money. A good mechanic you can trust is priceless.

Oil pressure sender @ black arrow below.

Thanks for the reply guys.

I actually changed out that sensor (the one in the diagram above) first but that didn't work. So I've still been trying to get to the bottom of things. The test gauge I bought has a pretty robust hose that won't bend very well - which is why I needed the elbow, there's not a whole lot of room in there.

The oil pump was replaced in March of this year (according to the records I have for the "new" engine) so I kind of automatically assumed that wasn't the problem. Does what RacerTodd said about his pump issues (and swapping out a relatively new one) hold true for PD engines?

I'm also curious about the oil weight suggestion. As I have no idea what kind of oil went in during the last change, is it REALLY possible that switching to Rotella T6 could cause the light/beeping to stop? It DOES seem to happen only when it gets hot - usually starting up well after the temp gauge gets to the middle.

Thanks again, I really appreciate the suggestions!!!!

I had a 1984 VW that would light up the oil light at maybe 2,500 RPMs if it did not see the oil pressure it wanted. I changed to a thicker oil and the problem went away. Note that a 1984 engine used a lot thicker oil than a 2005 TDI engine. If you wondered you could either collect an oil sample for analysis of contamination and weight, or you could change to a preferred oil but still not know if you have fuel leak diluting the oil.

Last time I had an oil light come on I shut down the engine immediately and called a tow tuck. Next day I changed the oil pressure switch and all was good. I would rather spend a $100 on a tow than thousands on an engine.

Do not assume that an oil pump was properly swapped. Do a google search for use of Plastiguage. You should find an explanation of bearing clearances and the effect of loose bearings on oil pressure.

Well...it wasn't the oil. I put in Rotella T6 5-40 and changed the filter and while it did take longer than normal, the light came on again. Hard to believe that any shop wanting to stay in business would do an engine swap and not inspect the cam. Same shop did an oil pump replacement in March (and I have a leaky front crank seal) so could it be possible they put the wrong one/a dodgy one in a few months ago? I've only had the car a month and its already making me nuts!

Sounds like you bought someone else's problem child.

First thing you must come to terms with in TDI ownership is most VW dealerships cannot be trusted to do quality repairs, or not scam you.

You really need to get some quality help, before you are in an even worse situation. Follow the advice in post #10, PLEASE!

Sharkey said:

Hard to believe that any shop wanting to stay in business would do an engine swap and not inspect the cam.

Click to expand...

If you are lucky enough to have this be just a cam issue then you should buy a lottery ticket too.

I'll be seeking professional help (for this anyway!), will report back with a prognosis.

Thanks for the suggestions/advice everyone, I really appreciate the help.