Syvman

iTrader: (1)

So I've read numerous posts that if an LT1 shows a loss of oil pressure during braking, it usually points to an oil pickup that has become detached from the oil pump. Unfortunately, I know my pickup is still attached (I can see it through the drain plug, and I cannot move it - I pushed on it with a screwdriver). I disconnected the oil pressure switch/sensor and plugged in a mechanical gauge - I have confirmed that the pressure is indeed dropping, ruling out the gauge in the car and the sensor/switch. SO, that means the oil pan is coming off tomorrow. Since I know the pickup is still attached, I need to be looking for something else that might be the problem. I noticed on another oil pump I have that there is a spring-loaded valve on the opposite side of where the pickup attaches - is it possible that this valve is stuck open?
I would appreciate any advice as to what I might want to look for after I get the pan off in the morning (well, afternoon - I figure it's going to take a few hours just to get the damn thing off). I plan on buying a new oil pump, but is there anything else I might need to check for? Is it possible that there's a hole in the pickup tube or something else?
Thanks in advance for any possible culprits!
-Terry

IronOutlaw

iTrader: (4)

How low is it going? Its normal for the oil pressure to drop when idling. My car drops to about 25-30 psi when idling but runs over 40-60 when cruising or revving. My old worn out LT1 car idled at about 10-15 when hot, and I beat the snot out of it everyday.

ls2pontiac

iTrader: (1)

My old motor used to do that on heaving braking, and if you accelerated hard. Sometimes it would straight up lose all oil pressure until you let it cool down and fire it back up. turned out the pickup fell off

Syvman

iTrader: (1)

It drops to zero... It also causes the "Check Gauges" light to come on for a brief moment. That's why I immediately thought the pickup had come off, but I can see that it is attached and stationary - so something else is causing the problem...

Syvman

iTrader: (1)

I just thought of one more thing I should probably mention before heading to bed tonight - the oil pressure hovers pretty low at idle after the engine warms up.
I tried adding a little bit of additional oil (not TOO much - probably 1/2 qt. or so - I'd say it was reading 1/8 to 3/16 of an inch above the normal range on the dipstick). I also tried a heavier-weight oil (10W-40 high mileage). None of those helped.
If anyone knows of anything else I should look for when (maybe I should say IF) the oil pan comes off, I would really appreciate the advice - have a great night everyone!

IronOutlaw

iTrader: (4)

Truthfully pulling the pan is not a fun job. you may want to double check with a mechanical gauge to make sure the oil pressure is really dropping that low. My stock electric gauge is very twitchy, even after changing the sending unit.

Syvman

iTrader: (1)

Yeah, I know removing the pan isn't fun. I wish it didn't have to be done. But if I know the pickup is still installed, then it must be something with the pump itself - unless I'm missing something...
But yes - I already tested with a mechanical gauge, and it is definitely dropping to zero. I hooked it up where the usual pressure switch attaches and just ran the hose under the back of the hood into the car through the window - probably looked a little goofy, but it was the only way I could watch it while driving and hitting the brakes...

wrd1972

iTrader: (12)

When mine did this it was clearly that the pickup had fallen off. If your convinced its still on, beats the crap out of me other than to say what you think your pushing on through the hole, is not the actual pickup. I just dont see what it can be other than the pickup.

ricekiller28

I had this problem happening to me, turned out it was very low oil level.have you checked that yet?

Intimidator02SS

One thought for you - I've seen once where the oil level was good, and had same symptoms you describe. The issue ended up being the oil took too long to return to the pan. Oil return holes in the cylinder heads and lifter galley were almost carboned up shut. While the engine was running it had very little oil sitting in the pan, which shifted to the front of the pan (away from pickup tube) during braking.
I'd try running the engine for a few minutes or so, cut engine off and check oil immediately. I think you'd have to be 2-3 quarts low for your symptoms to be present. Even though you may not be low on oil, the oil may just be sitting in the top end of the engine and not in your pan.
Good luck with it and keep is posted.

SS RRR

iTrader: (2)

And it won't if the dipstick already registered full and you add more. Probably a good idea to drain the pan back to the correct level or you can start having windage issues. Not sure if it has already been mentioned, but jack the car up and bang on the bottom of the pan to see if you hear the pickup bouncing around. This is a very popular problem with the stock pump and pickup since it's a press fit. If it is indeed the p/up then you should get the pickup tack welded onto the pump.
If there is that much sludge in the engine preventing good oil return all you would need to do is look through the oil fill hole to see if there is an abnormally high amount of sludge.

Intimidator02SS

Good point. Even if you can't see the return hole, you'll see how much oil is "hanging out" while the engine is running.

Syvman

iTrader: (1)

Well, I'm not 100% convinced - the only reason I say I think it's still attached is because through the drain plug, I can actually see the bottom of the pickup (the screened portion) and it looks like it's in the correct position (parallel with the bottom of the pan)... I pushed on it with a screwdriver and it's definitely firmly attached to something... Maybe it came loose and got jammed on something else? That's why I'm so baffled - the problem definitely seems like the typical loose pickup, but mine really appears firmly attached.

Yes, that was the very first thing I checked. And like I said, I added additional oil and THEN drained it and tried a heavier weight oil. I measured the oil I drained from the car and it looks like what came out was what went in.


Very interesting - I will have to check this. Simple enough to start the engine, let it run for a little bit, and then check the oil really fast. Heck, why not just check the oil while it's running? If it looks really low while it's running, that's probably a good indication that the oil isn't returning to the pan fast enough. I am skeptical that this would be the case, though... I should have mentioned a couple more things to all of you - the motor was recently swapped. The old one had an overheat and a bad tapping from the top end as well as a blown head gasket. So I hit craigslist and bought a motor from a 1994. During the swap, I decided to re-use my old valve covers and oil pan, because they were in better shape than the ones on the "new" motor... When we had those things off the motor, I was actually impressed how clean everything was. Of course, a carbon deposit in a small oil valley wouldn't be that apparent, so I will definitely check this before I put it on jack stands and start removing the pan today - I'd do just about anything to avoid that.
That does, however, bring up a different question - there aren't any differences in the oil pan between a 1994 and 1995, are there? I don't recall them looking different, but I didn't compare them side-by-side because I just assumed they'd be the same. I probably shouldn't assume like that...

I am back to normal oil level now with the 10W-40... I tried the additional 1/2 qt with the 5W-30 I had in previously - I have heard/read the horror stories about the motor with too much oil - not pretty.
I beat the heck out of the pan with my rubber mallet at first - but like I mentioned above - I decided to just find out if I could see it through the drain plug, and sure enough - I can. It takes some cussing, but I am able to see the screened portion through the drain plug and I pushed on it with a screwdriver - it's not moving, so it's definitely attached to something.


I want to thank all of you for your advice. I'm going to get started here in about 40 minutes - I'll take a look at the oil level while the motor is running and if it looks okay, I fear I am at the point where I will have no other option but to pull the oil pan. One way or another, I will definitely keep everyone posted - it sounds like I may possibly have a problem that hasn't been discussed at length here. If the pan comes off and we figure out what is going on, I will definitely post some photos of the culprit. Stay tuned, and thanks again!

Syvman

iTrader: (1)

Update:

Started the motor, let it run for a minute or two, and then I checked the oil. Looks like it's VERY low when the engine is running (barely registers at the bottom of the dipstick). I shined a flashlight down the oil-filler hole and I don't see ANY oil accumulation, so does that mean I have a valve cover full of oil on the driver's side? That's the only thing I can assume at this point...

SS RRR

iTrader: (2)

Take valve cover off, take pics and post.

trilkb

iTrader: (4)

This might seem dumb....what filter are you running?

Ive experienced low oil pressure lights at idle in 2 vehicles due to running fram oil filters. Switched oil Filter to Wix Or Napa Gold and the problem went away.

Just something to think about

Intimidator02SS

Hmmmm... The only thing I can think of now is the lifter area (under intake manifold) has a restriction with the return of oil. You have me stumped, but I believe you are heading in the right direction with it registering low while running or immediately after running.

Syvman

iTrader: (1)

I almost feel like the car is messing with me - I checked the oil again right after it was running for a couple of minutes and the level looks good. My dad decided he wanted to take it for a drive to "see what happens"... My fear, of course, was that "see what happens" would become "see motor detonate"... My father is a little stubborn and was convinced that there was sufficient oil pressure to drive the car, so he took it for a drive on the freeway. I didn't attempt to talk him out of it (if you've met my father, you'd know it would be pointless) - so off he went. About 20 minutes later he returned, motor still running, no knocking, no smoke, so I guess it didn't blow up. The post-drive report states that oil pressure is fine at any speed/RPM, but still nosedives to zero when the car is brought to a "spirited" stop.
So after that, we decided it was time to remove the valve covers and inspect, just as SS RRR has suggested. But that didn't happen today... My father decided he'd rather watch golf on TV than tear into the car today, so we are going to postpone the engine inspection until Thursday. Valve covers will come off first, then (if nothing looks out of sorts along the top of the heads) the oil pan will be next. Yes, I can work on it by myself, but I'm sure most of you can agree that it's more fun to share the knuckle-banging with company.
So Thursday it is - I guess I'll put this thread on hiatus until then. Probably for the best though - I'm currently on antibiotics for a small stomach issue, so I can't drink. Working on the car without beer just doesn't seem right.

To answer the other question - Yes, I am running a FRAM filter. Your comment makes me wonder if that could be a possible problem... I think the best way to determine that would be to get the car to 25 mph or so, shift to neutral, and then try a hard stop while keeping the engine RPMs up to keep the oil pressure higher (shift both feet over - I am not a talented road course driver that can operate the clutch and brake with one foot, haha). Of course, if the pressure drops to zero during that test, it would probably cause some damage if the engine is running at higher RPMs... Maybe it's worth a try. I will pick up a WIX or Purolatlor or whatever else I can find and give it a shot.

Finally, Intimidator - I would hope that I don't have a big collection of oil down along the lifters beneath the intake - but like I said, I feel like the car is messing with me because I did another check of the oil and it looked fine. But regardless, we'll pull the valve covers and inspect - not a horribly difficult job and will at least give some peace of mind if everything looks in order under there. THEN, unfortunately, it's on to the oil pan.

Thank you everyone for your advice, and I promise you all will be the first ones to know what was happening after we get it torn down Thursday. Stay tuned!!!

quik95lt1

iTrader: (7)

just sounds like theres not enough oil in it lol

SS RRR

iTrader: (2)

If this hasn't been asked already, when did this start happening? Had you done anything to the engine prior to this problem?