need help diagnosing oil pressure issue

[ticklechicken]

Here's how I noticed I had zero oil pressure:

30 minute highway drive, didn't notice any issues
Park for 1.5 hours
Start car, immediately notice oil pressure dash light
Check gauge, pressure at zero (typically around 50-60 ish, can't remember)
Turn car off, probably ran for 20 seconds like this
Didn't hear any ticking
Have car towed home

At this point, I was 50/50 on whether I really had oil pressure. Sending units and dash light switches fail often, but it was weird that they did it at the same time (as far as I could remember). I try to regularly keep an eye on my gauges, but who knows.


Initial investigation:

Checked oil level, was at middle of dipstick, last changed 800 miles ago
Disconnected sending unit, verified gauge did needle sweep with key on
Installed mechanical oil gauge in place of sending unit
Removed fuel pump relay
Turned engine over for 15 seconds
Mechanical gauge showed no pressure
Replaced fuel pump relay
Started car for 15 seconds
Mechanical gauge showed no pressure

At this point, I was confident I didn't have oil pressure.


Yesterday's tear down:

Oil pump looked fine

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The oil pump housing had a few scratches around half of its circumference. You can barely catch these with a fingernail.

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The oil pan wasn't blocked. Screen was clean and oil flowed from the pickup (red arrow) to the screen area.

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The oil passages in the timing cover seemed fine. The section that mates to the oil pan (red arrow) looked like it was sealing well. I don't see any indication of an air leak, but I'm not sure I know what I'm looking for there.

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Current thoughts
Did I falsely conclude that I don't have oil pressure?
Should I pull the crank next to check for a spun bearing? I'm told this can cause zero oil pressure.
What do I do next?


Other notes
This is my first Viper, and I've had it 6 months. My car often doesn't match the parts fiche I downloaded from Roe (using 1997 to avoid Gen 1.5 complications). Is this normal for Gen 2 Vipers?

My oil pan looks completely different. My pickup is cast into the pan. The fiche shows a tube with a round screen.
Roe shows 4 bolt main caps. Mine are cross bolted.
The oil filter adapter gasket is different. I ordered the part number on the fiche. It arrived and is wrong.

[Old School]

I'd check the oil pressure relief valve. I've had a couple stick open on other vehicles.

[ticklechicken]

I'd check the oil pressure relief valve. I've had a couple stick open on other vehicles.

Are those the two springs and plungers under the blue arrows? If so, how do I determine if they're stuck?

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[dave6666]

I had Dan Lesser repair a timing cover for me. He had to replace those parts during the repair. I would contact him for replacements. Viper Specialty Performance.

[GTS Dean]

The oil pan wasn't blocked. Screen was clean and oil flowed from the pickup (red arrow) to the screen area.

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I wonder why anyone would remove the anti-slosh baffle where the oil dipstick rests in the pan?

And another more important observation! Your trap door baffles are installed backwards!!! They need to swing toward the inlet screen. I would DEFINITELY pull the #3 rod cap and check the bearing insert and journal for wear or galling!

Be sure to put a drop of Loctite on all the phillips screws when you button all this back together.

[ticklechicken]

I wonder why anyone would remove the anti-slosh baffle where the oil dipstick rests in the pan?
I was wondering what those machining marks were. Here's a closer pic with the sheet metal removed. Weird.

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And another more important observation! Your trap door baffles are installed backwards!!! They need to swing toward the inlet screen. I would DEFINITELY pull the #3 rod cap and check the bearing insert and journal for wear or galling!
Just a bad camera angle. They open correctly. Here's a new pic. Also, why the #3 cap specifically? History of problems?

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Be sure to put a drop of Loctite on all the phillips screws when you button all this back together.
Thanks for the tip.

[AZTVR]

I was wondering what those machining marks were. Here's a closer pic with the sheet metal removed. Weird.
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[Old School]

The times my relief valves were stuck open, there wasn't really anything wrong with them, just a small piece of debris holding them open. They get oil directly from the pump, before the filter.

[Fatboy 18]

Do those Oil baffle doors swing both ways? looking at the pictures your door flaps seem odd? the upturned lip at the bottom of the door flap normally faces toward the centre of the pan not face forward
How to guide here http://www.kouchicentral.com/viper/oil_pan_baffle.htm

[GTS Dean]

That's what struck me as well. They are supposed to slam shut on one chamber depending on whether the car is on accel or decel. I think most folks bought the IPSCO kit, but there were others available as well. They aren't very complicated and I considered making my own before deciding there wasn't much for me to save vs a straight bolt-in. I left the factory cover in place on my car because there's only one place the oil can return to the pan, and that's right over the suction screen.40028

[ticklechicken]

The times my relief valves were stuck open, there wasn't really anything wrong with them, just a small piece of debris holding them open. They get oil directly from the pump, before the filter.

Thanks. I'll check that. My manual says to drill a 1/8" hole in the caps and use a sheet metal screw to remove the caps. I'll give that a shot.

[ticklechicken]

Do those Oil baffle doors swing both ways? looking at the pictures your door flaps seem odd? the upturned lip at the bottom of the door flap normally faces toward the centre of the pan not face forward
How to guide here http://www.kouchicentral.com/viper/oil_pan_baffle.htm

They swing properly (see post #6, 2nd pic), but it seems they look different than most systems. Car is new to me, so I don't know who made the baffles.

Thanks for that link. That will help with reassembly.

[ticklechicken]

I left the factory cover in place on my car because there's only one place the oil can return to the pan, and that's right over the suction screen.40028

Thanks for the pic. Since my car is modified, it's nice to see the stock configuration.

[Old School]

Thanks. I'll check that. My manual says to drill a 1/8" hole in the caps and use a sheet metal screw to remove the caps. I'll give that a shot.
That's the same method they used on small block Chrysler's 50 years ago.

[GTS Dean]

Thanks for the pic. Since my car is modified, it's nice to see the stock configuration.

You can see my IPSCO rear trap door in the photo, with the lower flange facing the sump inlet. At some later point in the Gen 2 production, they went to 3 large holes in the sump cover - 1 per section. I'm not sure if that coincided with the 10 qt. pan or not.

[ticklechicken]

By drilling a 1/8" hole and using a sheet metal screw, I was able to get a good hold of the cap with my vise grips. However, no amount of pulling would get the cap out. After I had the idea to use a body clip tool, it came out easy.

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After removing the caps, I removed the springs. They both are in good condition. Next, I tried to remove the plungers, and it seems the plunger near the bottom of the timing cover is stuck. Is this my oil pressure problem? I'm still trying to understand the details of the oil flow circuit, so I can't figure out how this stuck plunger would effect me. I found this info in my Google searching:

A pressure relief valve that is stuck open can allow too much oil to bleed off. This results in a lack of oil pressure...
A valve stuck closed will result in excessive oil pressure...

My plunger is stuck all the way into the timing cover. Is this stuck open or closed?


https://www.youtube.com/watch?v=tDljMV6NFcU

[Old School]

If you removed the spring first, in is stuck closed. The spring determines the pressure relief point.

But stuck near the bottom and stuck at the bottom are two different things. Near the bottom might be stuck open if it uncovers the window.

[ticklechicken]

Good info. Thanks. Using some calipers, I was able to determine that the stuck plunger was at the bottom of the hole. I was able to remove it using a dental pick. It wasn't jammed in that hard, but it did take some effort to remove. It doesn't appear damaged.

[Viper Specialty]

Screams stuck open PRV to me. Everything points to a "Real" OP issue.

Couple points:

1. It doesnt take much at low RPM to have no pressure with a stuck open PRV. The "cause" may never be found.

2. Like everyone said, check #3/4 rod bearing for piece of mind.

3. Since the pan is off, make sure all lifters are in place. I have seen one instance where the Pushrod popped out of place, lifter managed to break the dogbone and launch itself up in its bore enough to completely uncover the gallery and dump the oil system volume right back into the crank case. I highly doubt this is whats going on... but look around anyway.

4. Pump and cover actually look pretty good.

5. Make sure all oil gallery block plugs are in place. *someone* has been in that engine, double check everything.

[Old School]

I'll bet the valves themselves are directly out of another Chrysler engine, V8, 6 cylinder or something. But they had to use 2 because 1 didn’t provide enough volume.

[ViperTony]

5. Make sure all oil gallery block plugs are in place. *someone* has been in that engine, double check everything.

"Some people did some things." ;)

[ticklechicken]

I took the #3 and #4 con rod caps off. The grooves can catch a fingernail. I'm not experienced enough to diagnose these, but I'm guessing they need to be replaced. I'm going to pull the other con rod bearings next. Curious what they look like.

What's next? Could this be my oil pressure problem?

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[Old School]

Grooves are typically caused by debris, not lack of oil. You can use plastigage to checkthe oil clearance. What does the crankshaft journal look like?

[Viper Specialty]

Replace it because you are in their anyway... but that is absolutely not your problem.

[ticklechicken]

Screams stuck open PRV to me. Everything points to a "Real" OP issue.

Couple points:

1. It doesnt take much at low RPM to have no pressure with a stuck open PRV. The "cause" may never be found.

2. Like everyone said, check #3/4 rod bearing for piece of mind.

3. Since the pan is off, make sure all lifters are in place. I have seen one instance where the Pushrod popped out of place, lifter managed to break the dogbone and launch itself up in its bore enough to completely uncover the gallery and dump the oil system volume right back into the crank case. I highly doubt this is whats going on... but look around anyway.

4. Pump and cover actually look pretty good.

5. Make sure all oil gallery block plugs are in place. *someone* has been in that engine, double check everything.

Thanks for all this advice. I'll be calling you this week for parts.

1. Yikes

2. Done

3. I couldn't see every lifter with the con rods still in, but the 8 I could see looked good.

4. Good news.

5. Good idea. However, I'm struggling to find the quantity and location of these plugs. I have the factory manual, but I'm not seeing this info.

[Viper Specialty]

Three in front of block, three in back, two on top front. Top and back are exterior. It's obviously not them or you would have oil everywhere. Front three are behind the cam gear, you may be able to get a view with a small mirror.

[ticklechicken]

I got the car put back together a week ago, and it has oil pressure now. I drove it this week, and the problem hasn't come back. Unfortunately, I have no idea what I fixed. My new oil pump didn't fit (too thick), so i put the old one back in. After verifying oil pressure, I put the old sending unit back in to check it, and it works fine. The dash light is working too. Everything seems to be working, and I didn't change any parts. This convinces me that I actually lost pressure weeks ago, and it somehow came back. Puzzling, and a little unsettling.

Good news is that I finally got my power steering pulley swapped out while I had everything apart. Bad news is that my a/c doesn't work after reassembly.