Hey guys,
I swear by oil pressure, and I live by the guage. Today it acted up on me, and I'm a little nervous. Actually, I'm kind of freakin' out right now. Today when I started the truck in the morning, it started as usual, Perfectly.
This afternoon after school, I started the truck to come home and it took about 10 seconds for oil pressure to build, and then it was low at that. In that 10 seconds, I had a slight knock...But after my oil pressure finally built up the knock did go away. I didn't start driving the truck until I did have some pressure. Now on the ride home the guage was reading about 1/2, which is fine because it's still in the Normal Range on the gauge. It usually reads around 3/4.
What's up with this? My oil level is full. I've got 7k miles on this oil change. However, I've been adding about a quart a week...so I'm sure it's gotten some new stuff mixed in to compensate. I was planning on an oil change this weekend. Now, I'll try an oil change tomorrow night after school and see if that helps the case. Any ideas guys? I appreciate the help!

 

A quart a week? You may wanna check and clean your CDR.

Stock gauges aren't the greatest to rely on. You said there was a knock but by the time the oil pressure did come up the knock went away. Could be a leaky injector causing a knock, and the oil pressure sending unit going bad? Coincedence maybe?

Change your fuel filter, top it up with Diesel Kleen, start 'er up, let 'er run for 10 seconds. Shut down and let sit for a couple hours, even over night if you can. Then drive it like you stole it.

You can do the same thing with Auto. Trans. fluid if you don't have Diesel Kleen.

 

John, thanks for the reply!
CDR has been cleaned and serviced. Maybe a quart a week is a high estimate, maybe a quart every two weeks. I haven't really paid attenion, I check my oil every few days and top it off about 1/4 quart each time. I pour from a gallon jug so I'm not positive on my amounts each time...
I hear ya on the guages! My fuel guage has never worked, but I did get my water temp. and oil pressure to work with new sending units. I'm still saving up for good mechanical guages. I've been pretty confident with the oil pressure gauage working correctly.
The fuel system has about 8k miles on it, and I've gone through 4 sets of return lines kits between switching it over the current truck, doing the head gaskets, then fixing leaky o-rings twice. Between all the switching I've torqued the Injectors down equally with new copper gaskets each time. I will check if they're loose or have bubbles of fuel seeping out the threads.
Fuel filter is about 6 weeks old, I put a new one on when I did the head gaskets.
I had been running a quart of ATF in each tank except for the last 2 fill-ups, just because I was rushing. I'll remember from now on.
I did forget to mention the cold start in the morning was fine. Sounded perfect, and the oil pressure gauge bult up pressure like normal and no knocking sound.
I've mixed up my facts, the afternoon start was actually a warm start, when the oil pressure didn't build quickly and it knocked.
All in all, I'll keep my ears open tomorrow. It could just be a freak thing. I just wasn't sure if the oil pump was giving me a warning sign of failing in the near future...anybody have an oil pump fail?

 

Rare for an oil pump to fail. I would go ahead and change the oil, and keep an eye on it.
are you checking the oil hot or cold, This is kinda stupid but the dipsticks are designed to check the oil with it hot, if you fill it with oil cold you are actually overfilling it and it will burn it off pretty quick. I never fill it myself until it will hold at least 2 quarts and it has always worked for me.

 

Are you checking your oil cold or warm? It does make a differents. Should be checked warm.

 

A $15 mechanical gauge from any of the chain parts stores would be better then relying on the stock gauge. At least then you can know your normal range and anything amiss will make you start checking stuff.

 

I can't really help on the tech side but we just had an incident with ours towing. My brother was driving and he thought he heard a wierd clanging type noise from the exhaust while driving at 70mph.

Our manual gage also dipped and he just thought it was different.

He said the truck pulled really well throughout but pulled over to check the oil and he thought it was low at the dipstick. He put quarts in and the noise never came back on the trip home.

We have only had the truck a few months and this was our first new batch of oil/filter. We also serviced the oil cooler.

I had not added any oil to our truck thus far and now looking back it may have been a bad move on our part. We do not daily drive but now that I look back between a few trips we have driven the truck 2,000 miles. I am such a dummy because I wanted to check this stuff to see how much oil OUR truck was burning so I could keep an eye on it.

I will be able to see just how much we are talking based on the math later this week.

Also I cleaned up the cdr while we had it out, and yes it was all gummed up. I tried the basic blow by mouth test and just assumed all was well since I didn't see rubber chunks in my gas container I used to clean it.

Is it possible that this is not a good real world test though for a part that has been probably beat its whole life and not maintained and perhaps we should get a new one and start fresh?

Anyways just throwing stuff out there.

 

Woops! 80% of the time I check my oil cold, right before I leave for school. The other 20% of the time, It's warm. So I guess the oil I keep adding is just burning off. Oh well, live and learn!
I was saving up to buy all the guages of the same style and re-do a spare dashboard I have with custom guages, the type that are reliable and actually work! Mechanical guages, not the dummy guages either. Instead of waiting, I'll just get one of those cheap oil pressure units now to keep my mind at ease!
damac-clean that CDR valve again sometime soon. I had to do my CDR for a few hours at a time for a few days. How many quarts did your brother add?
Thanks for the replie guys, I'll see how tomorrow goes. Hopefully fresh oil and a filter will help too.

 

During the winter with 7k miles on the oil, I am going to say you are due for an oil change.

While you are under the hood, pull the wire off the oil pressure sensor and reinstall it.

 

I have heard that the factory guage is not graduated. Under 7 psi no reading over 7 psi it reads. Is this incorrect?

 

I don't recall the year but on your truck your thoughts are true. On my 87 though it's not the case. My gauge reads along with the increase and decrease in pressure. The reason Ford did the change was because too many people were complaining the oil pressure was reading low when warmed up, when in fact at idle as low as 10-15 psi is plenty of pressure. There is a mod you can due to yours to make it read real time, do a search, I think you take out a resistor or something on the back of the gauge cluster.

 

I don't know what year they started that but yea it is just an idiot light basically.

 

West Aussie here is a link though it's on a ranger it should be similar. It started after 87 with the idiot gauge. To convert yours you just need to get a sender for an 87-down and jump the resistor on the back of the cluster. Described here:
"Dummy" Gauge

 

Idiot light sounds like me anyway. lol. Actually I have a seperate oil pressure gauge anyway as I learned a long time ago dont trust the factory stuff. All VDO for me except the pyro which was in when I got the truck. So far I have BOOST, TEMP, PYRO, TRANS TEMP and OIL PRESSURE.