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Oil Pressure Dropped Off Issue

Thanks for all the replies!

Sorry, I meant 5 qts below full. But I will go back and verify today.

Sadly I didn't take a pic when I had the motor out of the inside of the oil pan. I did confirm back then (4 years and about 3000 miles ago) that the pickup was clean and tight.

I don't know about the condition of the oil pump. Is it possible that it can produce pressure, but at a lower volume as it's aged?
 
miller said:
Yes. If there's enough wear inside the pump, where the clearances are too large.
Click to expand...

This is true. As well bearing clearances. However, I don't think that is your problem. If it were, you wouldn't have the oil pressure that you do when you're cruising, and your light would start flickering at idle in gear when its hot. The pumps are way over designed and will go 250,000 miles. There would be signs all of the time, not just when you slam the brakes in 4 gear.
 
One thing the OP might consider...

Drain the oil out of the pan. Then, with the drain plug out, look inside the pan. You should be able to see if there are baffles. Run a stiff wire in there, to see if the pickup tube is loose.
Agree, sudden back off, pickup tube lost prime, from oil moving forward.
 
The factory tube is suppose to be just touching the bottom of the pan with no gasket when u go to install it. The gasket spaces it slightly off the floor of the pan. That is how they were designed. Everybody that adds clearance is creating a problem that wasn’t there to start with. The 402 pan is baffled. 1 qt above full will generally solve the problem u have. Kim
 
miller said:
One thing the OP might consider...

Drain the oil out of the pan. Then, with the drain plug out, look inside the pan. You should be able to see if there are baffles. Run a stiff wire in there, to see if the pickup tube is loose.
Agree, sudden back off, pickup tube lost prime, from oil moving forward.
Click to expand...

IMG_7984.jpg


I changed the oil a few days ago and snapped this pic. Can you guys tell anything? I believe all I can see is the pickup? Or am I wrong and the pickup is further towards the front of the motor?
 
67 GTX said:
Can you guys tell anything?
Click to expand...
Hard to tell, 67 GTX.
Yep, could be the pickup. You can see things much easier. That being said, and going by what 'you' can actually see...one thing that could be is, the end of the pickup, is too high. Bottom end of the pickup tube, should be not more than 1/4" from the inside bottom of the oil pan. (Looks much more to me.)
Is the pickup tight? Shouldn't be able to turn it.
 
Get a bore scope in there, then you’ll know for sure.
 
miller said:
Hard to tell, 67 GTX.
Yep, could be the pickup. You can see things much easier. That being said, and going by what 'you' can actually see...one thing that could be is, the end of the pickup, is too high. Bottom end of the pickup tube, should be not more than 1/4" from the inside bottom of the oil pan. (Looks much more to me.)
Is the pickup tight? Shouldn't be able to turn it.
Click to expand...

The pickup was very tight when I had the pan off the motor about 4 years ago.
The bottom of the pan does curve up a bit, but I see what you are saying.
 
Yeah. Bottom (open end) of the pickup, you want fairly close to the bottom of the pan sump. There, it should always be submerged into the oil, and no air is sucked in.
On mine, even had to get the right pickup for my pan. Once the pickup was installed, checked it, and was the same as the pan bottom. Toss in a couple gaskets, and a windage tray, came out just about a 1/4".
Can you tell if there's any baffles? Look 'up' into the pan, to see them. Most have a front, and rear plate, to allow the oil into the sump, and stay there. If none, could be your pressure loss problem. Hard starts/stops can move the oil in the pan, pretty good, letting the pickup pull air.
 
Hard stops and starts are why Mopar recommended to fill to the full line then add an extra quart. The old guys always told me I was gonna blow the seals out of the motor. Never happened. Still adding the extra qt to this day. Kim
 
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