oil pressure warning light

Wife began her morning drive only to call and turn around telling me the car had a big oil light on and a message about "oil pressure low turn motor off". upon getting home light and warning went away. I'm thinking its the HPOP? Any thoughts?

2 points: the oil pressure warning system is quite simple on our cars... a switch that closes at a moderate pressure (20 psi I think?) is hooked up to the cluster. Below 2000 rpm the pressure switch is ignored. (Yes, the car does not monitor oil pressure at idle).

I don't know where the oil pressure switch lives on our cars, I'd guess it's somewhere near the oil filter. Look for any broken wires. I would want to verify the car has oil pressure as well before running the motor any. Remember - starting the engine and not getting an oil pressure alarm does not mean there is oil pressure!

-J

I replaced an oil pressure sender on a friend's 2013 Passat TDI (about 110k miles at the time). It was leaking internally which causes oil to get on the connector. This creates high resistance and turns the light on. I still verified that it had correct oil pressure before allowing him to drive while waiting a few days for the part. The sender is located on the firewall side of the cylinder head below the engine hook bracket. Need to remove the intake tube going to the turbo and a few other things.

For starters, you can get to the sender, unplug it, and look for signs of oil inside the connector and sender. It is a very inexpensive part.

well, as it turns out I was about 2qt low on oil.

buzzie0013 said:

Wife began her morning drive only to call and turn around telling me the car had a big oil light on and a message about "oil pressure low turn motor off". upon getting home light and warning went away. I'm thinking its the HPOP? Any thoughts?

Click to expand...

Another point : any guesses whether it means turn the motor off now, right now, or to proceed to home, and then switch the engine off? Just how long was it run without oil pressure?

Chances are you now need a new engine.

^That may be a bit over dramatic, but letting the sump get two quarts low is not something you want to let happen again.

The oil was low enough to lose oil pressure, then the light came on, then the car was driven home. What is your prognosis?

Well, since the engine never seized, my prognosis is survival. How long the turbo and engine last in the long run- who knows. I imagine the car had intermittent oil pressure loss on hills, corners , whatnot as the remaining oil sloshed around.

...also depends on how far the car was driven...she turned around and returned home.

when oil level drops to a quart or 2 the oil fails to run back into the pan quick enough thus the pickup tube goes dry until enough oil runs back down creating a huge air pocket and running your crankshaft dry until oil reaches the pickup tube again. this pattern repeats itself for just a short time before the excessive wear creates such a void between the crank and rod that the little oil pressure present just cannot keep up. then the pickup tube goes dry for a lot longer- creating more wear and after a while a rod knock will indicate a complete rebuild and chiseling the melted mains off the crank.
Fun video of zero oil pressure:
https://www.youtube.com/watch?v=_2OnjIxxStM

Can't help but cringe at those no oil videos. Seems like a lot of them can run for a half hour or more with zero oil. Much quicker at full throttle of course.

Hmm. If this were my car I'd be considering doing the buyback now......

car runs and sounds absolutely normal. kind of curious how it became almost 2 quarts low now. thinking at last oil change (done by dealer) may not have filled it up completely. i will however be checking oil level every couple thousand miles now.

I would change the oil again regardless of mileage. There's a good chance that 2 quarts remaining suffered some thermal breakdown.

Hopefully lesson learned. After ANYONE works on my cars, I check fluid levels. If wheels were removed, I always re-torque. Even the best make mistakes.
Even if the light WASN'T on for a lengthy period, it's clear your engine was operated "xx" miles/hours with low oil. How far do you guess the car was driven after the light came on?

I'm in agreement with compu_85: re-reconsider the buyback for your car.

tdiatlast said:

<snip> After ANYONE works on my cars, I check fluid levels. If wheels were removed, I always re-torque. Even the best make mistakes.
<snip>

Click to expand...

This is worth repeating. I always check fluids. I've never had a surprise in 50 years of driving, but that's not to say tomorrow won't be the day. OTOH, I've never re-torqued lug nuts, and have likewise never been surprised. We have used a trusted tire store for close to 40 years for all purchases, installation, balancing, rotating, etc. I would urge anyone to do likewise.

mine snapped up a quart out of the blue (never used a drop before) on the oil change before last, hasn't used a drop since

Our local dealership has a buy 4 get 1 free deal on oil changes, so we have them do the oil changes on my wife's gasser. When I was last underneath her car, I noticed a small oil leak and traced it to the drain plug. I was able to tighten it to a firm snug with 3/4 of a turn. I mentioned this to the service manager, and he advised me that the car was last in for an oil change during the summer, a time when they have interns from local auto trade training programs working there. We also had tires put on her car, and the lug bolts were all highly overtorqued.

Not saying you have the same problem, but you can't trust the work being done to your car unless you do it yourself.

"Trust but verify."

Sometimes I re-torque the lug nuts, but the usual result is that they end up much less tight than they were. Most shops overtighten them, which is bad, especially if not even.

I confess to usually re-using the drain plug and washer, but typically add a smear of Permatex #2 to the washer. Never had a leak yet.