Solved 1995 Aerostar with a 4.0L engine. I have oil pressure at idle but not when driving.

[CLTuna]

1995 Aerostar, 4.0L, 118k
Four days ago I had to have my van pulled out of farm field too slick for me to drive out with this one wheel wonder. It was pulled out using the trailer hitch, van in neutral. After getting back on a road and driving it the oil pressure gauge needle started to move back and forth toward the "L" on the gauge. Once on the highway the needle went to the "L" and stayed there until returning to idle. Prior to this event the oil pressure gauge always read right in the middle of the range. There are no oil leaks and the oil level is where it should be. Haven't changed oil for a while. It has 10w-40 in it.

Drove the van 15 miles during the next 3 days with no noises and the gauge continuing to move back and forth.

This morning it was -4F outside and when I started the Aerostar there was a very loud lifter noise. No pressure showing on gauge. I didn't drive it. Later this afternoon when it was 10F I started it again and the lifter noise was worse. I left it to idle while I went inside to call a ford guy. He said it must have some pressure or it would have stalled or seized. After 10 minutes in the driveway idling I returned to find the gauge in the normal position and the lifter noise almost gone.

I drove it for about 10 blocks round trip and the oil pressure gauge dropped back to "L" and soon after the lifter noise began again. Now it sits and I came here to see if I could find an answer.

 

[Josh P]

With the factory gauge it only takes a few lbs of oil psi to read in the normal range, so the best thing to do is get a mechanical gauge hooked up to the engine to see how much pressure you really have. If the van never had lifter tick before this happened I would suspect the oil pump or the oil pump drive is worn/stripped. The pump drive is easy to get to through the doghouse.

 

[BrooklynBay]

Welcome to this forum! Oil filters have a one way check valve. You said that the oil wasn't replaced in a while. Maybe the built in check valve is stuck or clogged?

 

[CLTuna]

Thanks for your quick comments.

(Josh P) How would I know if the oil drive is stripped?

(BrooklynBay) So I should change the oil without doing a solvent soak of the oil pickup screen? Read quite a bit about a clogged pickup screen causing similar issues.

Hope to explore the issues tomorrow.

 

[BrooklynBay]

Flush the engine with motor flush or Seafoam, then replace the oil & filter.

 

[CLTuna]

How do you flush an engine?

 

[BrooklynBay]

Pour motor flush or Seafoam into the crankcase, then let the engine run for a while until it reaches the normal operating temperature. You could drive locally for a little while but not for more than a few miles. Drain the engine, replace the oil, and the filter.

 

[CLTuna]

Thank you.

 

[don-ohio]

Yes,it sounds like oil filter is plugged.Do as Brooklyn says, but really I'd change the filter FIRST,then trun the flush,then change oil and filter again. That's just me being cautious.Oh,and in this colder weather, 10W30 might be a better choice until summer. don-ohio ^)

 

[Josh P]

You would have to pull the oil drive gear to inspect it. How long have you owned this van? what mileage interval on oil changes? How does the oil look, coolant or gas mixed with the oil will kill the pressure.

 

[don-ohio]

Get that filter off there. That's priority numero UNO! don-ohio

 

[CLTuna]

Yes Don thought that made sense too!

So far today;
-Replaced filter with new FL-1A
-Dropped about a pint of oil
-Added a pint of seafoam at the filler
-Let run for 25 minutes
-Tick almost silent, but no oil pressure reading on dash gauge.
-Drove back into garage, shut off and restarted
-Tick back but not as loud.

Not sure how to post pics. From auto parts online I believe I found the sender on the driver's side front, bottom of engine.

Next step is run for a manual oil pressure gauge and check. Will likely purchase a sender too!

Bought a couple cans of B-12 that I was going to soak the oil screen in after dropping the oil. (Yes or No)

 

[CLTuna]

(Josh P)
You would have to pull the oil drive gear to inspect it. How long have you owned this van? what mileage interval on oil changes? How does the oil look, coolant or gas mixed with the oil will kill the pressure.

Owned the van since new. Don't drive it much but oil changed every 5k. It's been a year and a half since last change. Oil looked dark but not cloudy or foamy. May not know about the coolant until I drop all the oil. Wanted to manually check pressure first.

 

[CLTuna]

(Don-ohio)
Oh,and in this colder weather, 10W30 might be a better choice until summer.

I was going to use a cheap 5w-30 oil for first change, if noise gone I would replace oil and filter again after 4 hours of driving.

 

[BrooklynBay]

You have several ways to post a picture. Click the go advanced box under the quick reply box. You will be taken to another page which says manage attachments. This will allow you upload a photo directly into a post. The next way is to purchase an elite membership to obtain access to this site's photo gallery.

 

[CLTuna]

Thanks about the attachments.

Checked oil pressure with mechanical gauge. "0"

What's next? Oil pump shaft drive gear? If so, where is it on a 4.0L Aerostar?

Thanks for staying with me on this.

 

[CLTuna]

I connected the mechanical gauge to the port used for the oil pressure gauge.

 

[Josh P]

Pull the doghouse cover. Right above the top bell housing bolt toward the right side you will see a bolt holding a plate that is half round on one side.

 

[CLTuna]

Josh, any certain tool needed to pull it?

 

[CLTuna]

Called Ford; it's called a camshaft position sensor transducer. It has the oil pump drive gear attached. F3TZ-12K-073A (obsolete) Dorman 30S2605 or Cardone 84S2605. I'll open the dog house tomorrow and check for wear.