Oil Pump going out or something else?

[bigja01cobra]

Here is the situation, a while back I was driving to work and noticed the Oil pressure hit zero while sitting at a light. Thought maybe it was bad sending unit, but by the time the light turned green the motor started making noise...similar to dry start up after oil change. I immediately pulled off and called my buddy to bring my trailer. When I went to load it on the trailer it started and had normal oil pressure. Upon arrival at home I started it on the trailer again it had normal oil pressure no engine noise. I unloaded it and let it run for a few minutes, then oil pressure dropped to zero again. I turned car off and parked in garage, was pissed and did not want to deal with it.

Today I changed the oil, it was the dirtiest oil I have ever seen and the oil filter weighed a good 2-3lbs, it was allot heavier then normal. Only 2800 miles on the oil, Mobile 1 full syn 5w20 with mobile 1 filter. I changed to fresh 5w20 Mobile1 with a Ford Filter. Put 6 quarts of oil in...just below max line.

I fired it up...slight dry start but pressure built immediately and noise went away motor ran perfect. I drove it 5 miles to town and 5 miles back after letting it idle for approximately 22mins with me starring at the gauge the whole time LMAO. Before leaving the fans had kicked on so it was at operating temperate. Got home oil pressure was perfect and the motor sounded great. Outside temp around 92F.

35mins later friend comes over we go for a ride. Back Roads 30-50mph 25-30min drive time. Again no issue, when I arrive home I stop so he can get a photo and a sound clip. After sitting for about 2 mins, the oil pressure drops motor made no noise. I immediately cut it off. 30 secs later I restart motor and oil pressure is back up and normal, I rev it to about 3500rpm and let it settle oil pressure is fine.

Sorry for being so long winded but I wanted to cover the whole situation.

I think I can rule out worn mains....since oil pressure comes back immediately after it drops and the built motor only has 26K on it. Anyone else think differently?

Doubt it is pressure sending unit since when oil pressure did drop the motor did make noise. ??

Could it be the oil pump is starting to go out?


BTW Car is 2001 Cobra. Forged 5.1L 4V 11-1 compression worked heads cam.


Thanks for any input.

 

[01yellercobra]

Is that the stock gauge or an aftermarket gauge? If it's the stock gauge I'd get an aftermarket on there to see what's going on.

 

[bigja01cobra]

Yes I am just going off my stock gauge. Need to buy one for another car, so I will get one put it on this to see.

Thinking about just dropping it off at ford to let them put a oil pump in for me. They can check pickup tube and everything else while they are in there too.

 

[01yellercobra]

I'd make sure it's the pump first. That's not an easy thing to replace.

 

[Gallows]

I wouldn't start it again until I installed an after market gauge. When you changed the oil were there any metal filings mixed in with it? Did you cut the old filter apart to see why it was so heavy?

 

[bigja01cobra]

I strained oil through a fine mesh strainer...nothing showed up. I am dropping the car of to ford tomorrow...they are going to do diagnostic on it make sure it is the oil pump. I am contemplating sending a sample of oil off to get tested to see what they say.

I am going to cut the filter apart tomorrow to check it for metal aswell.

 

[Parts-is-Parts]

Sounds like the pickup is blocked.
In any case, there is no.getting around this one...that engine has to come out.

 

[bigja01cobra]

Ok cut oil filter open...no metal anything...Nothing reflects light. Nothing stuck inbetween filter folds. Other then being really gunked up. little bit of particles in the bottom of filter..but I cut it with a hacksaw so. If there was engine damage it should definitely be in the filter folds.

You can do the oil pump without pulling the motor . Can you not do the pick up? Drop the K-member?

 

[330mach1]

when i've replaced oil pumps i just drop the k member, not worth pulling the engine to replace a bad oil pump if caught in time

 

[01yellercobra]

Ok cut oil filter open...no metal anything...Nothing reflects light. Nothing stuck inbetween filter folds. Other then being really gunked up. little bit of particles in the bottom of filter..but I cut it with a hacksaw so. If there was engine damage it should definitely be in the filter folds.

You can do the oil pump without pulling the motor . Can you not do the pick up? Drop the K-member?

You'll have to drop the k member to get to the pick up. There's not enough clearance to get the pan off otherwise.

 

[bigja01cobra]

Thanks guys. I am going to let the dealership do their diagnostic and see if they are willing to do the pickup at a decent price.

I figure it should be less then 800 for oil pump and pick up install. What do you guys think?

 

[01yellercobra]

Depends on the dealers labor rate. In order to get to the pump all the stuff on the front of the motor has to come off. Plus either dropping the k member or pulling the motor for the pick up.

If it was me doing it I'd probably pull the motor to get to everything. And every shop I talked to was around $1500 for pulling and replacing a motor.

 

[bigja01cobra]

Yup shop charged me 1600 to do short block install last year. Oh well better then a whole new motor lol.

Thanks

 

[GoatSlayer]

I am in the same situation as you. But for me i got pissed and punched the damn car in the headlight. My tuner told me to change the oil and filter and get a new pressure sender unit and my pump is 3 weeks old. Hopefully mine is not a big problem but i will find out on the weekend.

Did you try to change the oil again and see if it came out dirty for the second time? The new oil could be gunked up, while cleaning out the gunk that was left after the first oil change thus dropping pressure after oil change.

 

[bigja01cobra]

Well I was supposed to drop the car off at ford again today. But work called me in so I will have to wait until Monday.

Yeah I have about 24,000 miles on this motor.

That is a good idea. I will change oil again this weekend and see if it is dirty again. Might be way it got reclogged, after 1hr of run time and stuff might have
broke some of the gunk up and reclogged it.

I will let you know what is up.

 

[DuffManRHA]

What oil pump are you using? After my 5.0 engine failure I am paranoid about oil pressure, and so far my Cobra motor is fine; makes about 100 (max gauge reading anyway) at cold startup, and when warm idles around 30-35, and up to 75 when driving normal. Is it possible that the pump is fine, as in the gears aren't worn or anything, but that the bolts that attach the pickup to the oil pump are loose? I would think it it was blocked, you would get almost no pressure at all, and have some type of damage that would show up in a naked-eye oil examination and/or cutting the filter?

 

[Gallows]

What oil pump are you using? After my 5.0 engine failure I am paranoid about oil pressure, and so far my Cobra motor is fine; makes about 100 (max gauge reading anyway) at cold startup, and when warm idles around 30-35, and up to 75 when driving normal.

Do you have a stock or after market oil pump? Regular or synthetic oil? My Aviator swap is making the same pressure with a factory pump and 5W30 oil. I thought it was pretty high for any engine.

 

[DuffManRHA]

Its the super expensive Melling oil pump, goes for like ~$300 IIRC from Summit. I thought it was high too, but I guess for modular engines its not? I run Motorcraft 5W-30 and a Motorcraft filter, still have the factory oil pan, pickup, and Cobra oil cooler on it as well.

 

[bigja01cobra]

I am running factory ford pieces from ford. Only paid like $80 for my factory oil pump. 5w20 Full synthetic oil as well.
Motor was broke in on conventional motor oil, Only Mobile 1.

Yeah since I did not see any evidence of motor damage...no metal in oil or in the filter leads me to believe it is something else. But if there was metal, I would be pulling motor and having it rebuilt. Ford will be looking at it soon and they will let me know what they think is up.

The guy working on it is an avid racer and builds allot of motors and cars in his off time, so maybe he will figure it out.

Another shop in my area just wanted to pull the motor and replace/rebuild. Not even willing to try and figure out what was up lol. $850 to pull it $3k to machine shop to machine motor and check heads another $1000 to build and install, then $250 for retune. LMAO. And on top of that they said it would take 3-4months LMAO.

Needless to say I picked my car up the next day.

 

[GoatSlayer]

I am running factory ford pieces from ford. Only paid like $80 for my factory oil pump. 5w20 Full synthetic oil as well.
Motor was broke in on conventional motor oil, Only Mobile 1.

Yeah since I did not see any evidence of motor damage...no metal in oil or in the filter leads me to believe it is something else. But if there was metal, I would be pulling motor and having it rebuilt. Ford will be looking at it soon and they will let me know what they think is up.

The guy working on it is an avid racer and builds allot of motors and cars in his off time, so maybe he will figure it out.

Another shop in my area just wanted to pull the motor and replace/rebuild. Not even willing to try and figure out what was up lol. $850 to pull it $3k to machine shop to machine motor and check heads another $1000 to build and install, then $250 for retune. LMAO. And on top of that they said it would take 3-4months LMAO.

Needless to say I picked my car up the next day.

haha stay away from that shop. :beer: