No Oil Pressure On Cold Start???? Knock Knock Knock Knock!! Help

[cturboaddict]

ok, for the past week ive been noticing a disturbing trend!
When i first start my car up in the morn, everything is fine, but after driving to work~ when i start it up for lunch the oil pressure gauge reads nada, and you can here the motor knocking for about 3 sec. then the needle pops up and the knock goes away!
Park the car after lunch, when i start it up to go home, it does the same thing! BUT if im driving the car somewhere and shut it off to go in a store or something, when i come back out IT DOESNT DO IT???? First thing in the morn IT DOESNT DO IT?????
Whats the deal?

 

[MustangPunk302]

You check your oil?

 

[pnawang]

sounds like lack of oil pressure or the oil pump is on it way out. how
many miles on the engine? maybe time for a rebuild. good luck

 

[cturboaddict]

yes, ive checked the oil, its fine! Burns a little here and there but its nothing much!
Motors got 110,000 on it now!

 

[MustangPunk302]

I bet there's something messed with your oil pressure sending unit.

 

[forced88lx]

Go replace your oil pump. Theres nothing wrong with your sending unit.

This is what happens:

When the car is cold the metal/seals in your oil pump SHRINK. Thus the suction of the pump is terrible. Once the oil gets hot, the pump seals swell and it acts fine.

So When you go to the store and start your car, it's seals are already swollen and it operates fine, however if you let the car sit for hours, you dont have startup oil pressure.

The knocking you are hearing is your lifters

 

[HISSIN50]

Go replace your oil pump. Theres nothing wrong with your sending unit.

This is what happens:

When the car is cold the metal/seals in your oil pump SHRINK. Thus the suction of the pump is terrible. Once the oil gets hot, the pump seals swell and it acts fine.

So When you go to the store and start your car, it's seals are already swollen and it operates fine, however if you let the car sit for hours, you dont have startup oil pressure.

The knocking you are hearing is your lifters

that is all well and good, but he says he has good pressure when the car sits all night and goes in the morning. that negates your theory, no???
it may still likely be the pump, but im curious for someone to have an explanation.

 

[brianmef]

If it knocks, it isn't getting oil. It wouldn't be the oil pressure sending unit. From what I've read here, it's acting normal! No oil pressure = no reading on the gauge = no oil getting to vital parts in the engine = you will eventually ruin this engine if you keep driving it. Take it in to a mechanic. I agree with forced88lx. It's the oil pump.

 

[cturboaddict]

actually it was the fram oil filter! I replaced it, no problem! Next oil change i put a fram in, after a couple months SAME PROBLEM!

 

[brianmef]

actually it was the fram oil filter! I replaced it, no problem! Next oil change i put a fram in, after a couple months SAME PROBLEM!

So replacing the filter fixes it for a while and then it does it again? How many miles in between oil/filter changes?

 

[cturboaddict]

trust me when i tell you! Look at how old this post is! after i replaced the fram with a ford motorcraft i had no problem for 3500 miles, replaced it with a fram 1200 miles and it started again!
Its the backflow valve in the filter!
Look it up, you will see similar reports of the same problem!

 

[brianmef]

trust me when i tell you! Look at how old this post is! after i replaced the fram with a ford motorcraft i had no problem for 3500 miles, replaced it with a fram 1200 miles and it started again!
Its the backflow valve in the filter!
Look it up, you will see similar reports of the same problem!

I guess I'll stick to Motorcraft then. Thanks for the info. I didn't realize that this thread was soooooooo old. I'm out-a here!