JWBerk94Z

Hey guys, I noticed something odd on the way home today. My oil pressure gauge (stock) usually reads right in the middle when I am cruising down the road. Well, I pulled out from a light today and punched it. Out of the corner of my eye I thought I saw the gauge take a dive. So, I slowed down, had pressure, and hit it again. Pressure would rise like normal and then fall after I was accelerating for a second. It kind of worked like the gas gauge does when accelerating/braking. I never noticed this before and I wouldn't expect my car to be doing this. Have I just overlooked this all along or what? I wouldn't think it would be normal, but the gauge doesn't go too low. I checked, and yes my oil level is on full. I am stumped and a little worried. What do you think?

TIA

Lyle A

Does it also drop under hard baking? If so, it's possible your pick-up tube fell off the oil pump.

atljar

Pretty common from what i have read on here. Mine does it too. Fine up uptil 4k and then i start losing pressure. Stats at 50 and will end up at about 30. No real answer for you, some think its crank windage. I havent noticed any ill effects from it, but it isnt a good thing for sure.

BoobSter-lt1-z

I have oil pressure dropping problems too with the stumbling. The following is what I have experienced...:
My oil pressure will stay at 20psi at a red light but in traffic when the car
the temperature gauge reaches the 3rd line my oil pressure at a red light is at like 17psi. If i punch it from a stop it will stumble really bad and hesitate until the RPM's get to 2k and then it will pick up and run fine
-> I have an oil leak above the oil filter and anytime i use any oil less than
20-50 it will leak really bad. I noticed that with 20-50 the oil pressure stays
a little bit higher and the stumbling does not happen as bad and the leak is
only 2-3 drips overnight
--> I am not the DO IT YOURSELF type of guy with cars but i think that because of the oil leak the gasket possibly for the oil pan has worn out and this is preventing the inside to prime (keep pressure) so this is possibly the reason for the dropping of the oil pressure. Same thing happens with pool pumps..when there is a worn gasket with a small drip on the circulation motor for the water, the water pressure will drop and the circulation of water is poor.......

Dont know if this helps but might be a possibilty......

FastZinTennessee

JWBerk94Z- that problem is pretty common on LT1's, and chances are it has been happening for a while and you just haven't noticed. Most people are accustomed to keeping their eyes on the road when really getting into the gas rather than looking at the gauge cluster.

I have the same symptoms as you, and noticed that a thicker oil helped get rid of most if not all of the problem. 10w30 would still drop pressure like you are talking about, but 0w40 Mobil 1 worked very well. You might try it. Also, a lot of people refer to this problem as "oil pump cavitation". There really aren't many facts about what is going on out there, but if you ever have some free time to sit down and sort through a bunch of threads, you might try a search on it.

Tally_96_ws6

Its most likely ur Oil Pick up tube. I have the same problem only sitting at idol though it will drop to arounf 15-20 then stay at 40 while driving.

JWBerk94Z

Yeap, it does that too. I didn't think that was odd, I had a mechanical gauge on my old 3rd gen and the oil pressure always worked like that even when I put the new motor in it. But it never dropped under acceleration.

My car doesn't do it turning or braking, just accelerating. Hmm, so it is a common thing huh? It doesn't seem real healthy. Thanks for the replies guys. Does anyone else have a comment? Should I just drive it and not worry about it? I have been taking it easy the last few days so it wouldn't lose pressure.

TIA

Larry T/A

I had the same symtoms. Replaced the oil sending unit problem went away.

fesgali

How much is it to change the oil pick up or send back tube?

JWBerk94Z

Oil sending unit? Hmm, you mean that cylinder looking thing with the 90* fitting that goes into the back of the manifold off to the side of where a distributor is supposed to be?

I would bet it would cost a pretty penny to have the pickup tube and/or the pump changed. I don't think you can get the pan off without pulling the motor or dropping the K-member. Someone correct me if I am wrong, I have never done it. I did look at it the other day and that is how it appears to me.

chy20k1

i changed my pump by lifting the motor up maybee 5 - 6 inches. i have an a4 btw.

FastZinTennessee

Oil pan/pump can be removed by jacking the motor up to get clearance. Just remove the low oil level sensor before pulling the pan out or it will break

brandboZ28

I went through something like this just a week or so ago. For starters, with oil in the pan, take a rubber mallet and hit the bottom of the oil pan pretty hard but not hard enough to dent anything. Another option is to hit the bottom of the pan with the side of your fist, I promise you wont dent it then unless you are one bad **** If you hear something metal move around in there, your oil pump pickup tube has fallen out and you will need to drop the pan and have it put back in. I would also suggest having it brazed into place keeping this from happening again. If the pickup tube is still in its original location(you hear no noises when hitting the oil pan), start with the sending unit. In 93 and early 94 models, its located right above the oil filter but on late 94-97 models, the sending unit is located behind the intake manifold. Its roughly a $25 piece at AutoZone or any local parts house. If it gets this far, inspect all the wiring going to the sending unit. Make sure its not burnt or stretched. Lastly, your stock gauge could just be going kooky. It happens sometimes. Best thing to do it to hook it up to a mechanical gauge and see whats really going on and go from there. Good luck with it.

Larry T/A

[QUOTE=JWBerk94Z]Oil sending unit? Hmm, you mean that cylinder looking thing with the 90* fitting that goes into the back of the manifold off to the side of where a distributor is supposed to be?

Yes that is the oil sending unit, sits on the back on the intake. It cost somewhere between 35 and 45 dollars.

FastZinTennessee

My pickup tube was in place, replaced oil sending unit for an unrelated reason and the oil pressure still dropped during hard acceleration. The only thing that fixed or mostly fixed the problem was a different weight of oil.