No oil pressure

[5150]

Using factory gauges on my burb with a 03 Tahoe 5.3.

Tapped the little piece on the drivers side of the pan like a lot of guys do but not getting any oil pressure when I crank it. I know that you can't just take out the distributor and use a drill to get your oil a little help, but I'm not sure what I'm doing wrong.

[BR3W CITY]

I've noticed that about 90% of oil pressure problems is attributed to only a few things.

1. If a regular gauge, the 1/8" nylon feed line may be kinked. In my case, the ghetto parts store nylon line ripped at a seam, and weeped only when hot. This is not a disaster, as your engine still has pressure...just the gauge doesn't.

2. You replaced the timing stuff and/or changed or removed the oil pump pickup tube (when switching to another pan). If you didn't use the correct o-ring, didn't secure the flange, or a burr or similar caused it not to seat. Sometimes the o-ring rolls out as you insert the pickup into its hole. It bleeds oil pressure out the bottom. This IS a real problem as the pump is bleeding off pressure and never getting up to the valvetrain. You can take off the pan to look, or even see if the bypass area (where your gauge is tapped) is even getting oil. You can also pop a valve cover off and bump the ign. You might spray a little oil out of the pushrods, but at least you can verify its working.

3. If its a digital gauge, make sure the sending unit is correct and matched to the gauge itself. Also, make sure the wire is actually attached to the sending unit. Many times I've seen a spade terminal just *bumped* during an oil change, and sure enough 0 oil pressure. Thats a dumb-luck kinda mistake, but no real harm is done.

[truckdude239]

did you drill the hole all the way though or just tap the open part?

[ls1nova71]

Has the engine sat for a long time with no oil in it? I've had oil pumps go dry and not be able to pick up the oil since the pump isn't submerged in the oil. Last one I did that didn't prime up I had to overfill it with oil to get the pump below the oil level, that way it would prime. after cranking it for a while, it got pressure, then I just drained some oil back out of it. Messy for sure, but it works. Some people say to go ahead and start it, and it will build pressure faster than just cranking it with the plugs removed, but that makes me a little leary.

[5150]

Originally Posted by ls1nova71

Has the engine sat for a long time with no oil in it? I've had oil pumps go dry and not be able to pick up the oil since the pump isn't submerged in the oil. Last one I did that didn't prime up I had to overfill it with oil to get the pump below the oil level, that way it would prime. after cranking it for a while, it got pressure, then I just drained some oil back out of it. Messy for sure, but it works. Some people say to go ahead and start it, and it will build pressure faster than just cranking it with the plugs removed, but that makes me a little leary.

How much more did you put in it?

[homemade87]

I did the same with no oil pressure at cranking. I cranked on it off and on for about a minute and got nothing. So I decided to start it and the pressure came right up. I looked to see what the guys at ls1tech was doing and most all had the same problem. They all seemed to just start it up and pressure came right up. Seems the starter cant turn it fast enough to get the oil to the pump. The three I did I just started it up with no problem. Just keep your eye on the gauge at start up.

[ls1nova71]

Originally Posted by 5150

How much more did you put in it?

I don't remember exactly, but I think it was around 10 or so. I also had the back jacked up as far as I could. I think if you've torn the o ring, it would build pressure with it overfull, but when you drain it back down, you may loose pressure again. Hope you don't have to pull the engine again, I know that will be no fun.

[akdg87]

it can take quite a bit of cranking to build oil pressure, i just did mine the other day and i had a new pump packed with assembly grease. But when it did start the oil pressure came right up, although i wasnt getting any while cranking.

[5150]

I'm pretty sure I'm going to have to drop the pan no matter what. We talked to Br3w City over the weekend and we think it may be the o - ring. I figure if I can overfill it and get something out of the line I'll feel better about the problem.

[5150]

If that happens at least I'll know that's the issue for sure.

[BR3W CITY]

Hehe, I was afraid this was gonna be the case when I called you and your friend the other day. That dang o-ring has gotta be the cheapest fix with the most labor, bar none on these cars.

[5150]

Well, I'm praying that I put another 5 quarts in and it gets pressure. Then when I drain those 5 or 6 quarts out it STILL has pressure. Don't think I'll be that lucky though.

[Jon01]

Pull the pressure sender that sits behind the intake out and crank to verify it's not moving oil before you do anything.

[5150]

Well, I put another 5 quarts of oil in it, aired up the rear really high and aired out the front. This way all the oil would be at the front of the pan where the pump is. Cranked on it for awhile and still no oil pressure through the line.

Dropped the pan and oil pump tube. Which o-ring do I have and do I have the correct one?

[5150]

Here's a pic of what the motor is in:

[BR3W CITY]

Hey Bryan, is that the truck pan or the H3/lh8/hot rod pan?


The truck pan uses pickup 12563961
and o-ring #12563963 (black rubber)

the lh8 pan uses
pickup 12608593
o-ring 12584922 (red)


And the burb looks good. There's one near me on CL that I've been tempted on, but putting some more atmosphere into mine might take priority.

[5150]

It's a F-body pan.

So I need the pickup AND the O-Ring for the truck? or Tahoe in this case, but I'm sure they're the same.

[smoky02]

The f body o-ring is different as I recall. That's what I'm running. But you should be able to call your local parts store and pick one up. Also make sure that it's the same color as the one you've got. Apparently they are color coded.

[Hart_Rod]

Originally Posted by 5150

It's a F-body pan.

So I need the pickup AND the O-Ring for the truck? or Tahoe in this case, but I'm sure they're the same.

Originally Posted by smoky02

The f body o-ring is different as I recall. That's what I'm running. But you should be able to call your local parts store and pick one up. Also make sure that it's the same color as the one you've got. Apparently they are color coded.

There's a red and a blue o-ring used on most applications. Since you have a F-body pan, you neeed a F-body pickup AND and the correct o-ring to go with it. You need to make sure that the o-ring matches whatever pickup tube you have. That's where the difference is.

Check this thread out:

http://ls1tech.com/forums/generation...verything.html

[Hart_Rod]

More o-ring info: http://67-72chevytrucks.com/vboard/s...d.php?t=582704

[Jon01]

F-body o-rings are different, I think truck pickups can be made to work with f-body pans.
Your o-ring should match whatever your pickup tube is from.

[5150]

Can anybody tell me which tube I have? It's been so long I honestly don't remember. I'm pretty sure when I bought my F body pan it came with the tube and tray. Which means I had the correct tube the entire time.

[ls1nova71]

Originally Posted by 5150

Can anybody tell me which tube I have? It's been so long I honestly don't remember. I'm pretty sure when I bought my F body pan it came with the tube and tray. Which means I had the correct tube the entire time.

F body tube is about 4 1/2" tall and about 14" long, truck is about 17 1/2" tall and almost 18" long. I don't think you'd get a truck tube in an F body pan without some serious mods.

http://s1331.photobucket.com/user/33...tml?sort=3&o=0

[5150]

Rob, I haven't had a chance to look at your links yet so that may contain my answer.

[BR3W CITY]

For the life of me I can't tell which o-ring is on there, I'm colorblind as all hell.

It looks like the fbody pickup tho, based on where the indent in the pan is, and where the head would sit in the sump. The truck tube is a different p/n and sits a bit parther back, because of where the sump point is.

Currently, the black seals and occasional green seals have been phased out, and I only see two current listings.

A blue seal, called first design for the fbody's and 99-00 trucks. OR a RED seal, for pretty much everything else, up to o8.