AHH NEW PROBLEM, LOW OIL PRESSURE

[stangbang302]

alright so after i got the fuel pump workin and car fired up i went for a drive, after about 10 to 15 mins of driving i went to go drop something off at home and head back out, but i noticed a big lack in power and oil pressure dropped alot. i really hope its an oil pump instead of spun bearing. any advice?

alright so i checked the oil to see if it was low. and it seems to have gas mixed in the oil. also when the car is cold it fires right up. but when its warm its harder to start up, feathering the gas pedal to get it fired up. tomorrow i will do a compression test.

 

[$pit]

Is the car carb'd or fuel injected? How much gas in the oil are we talking? What did the oil pressure drop to and are you using a mechanical gauge? Are you getting any valvetrain noise?

 

[stangbang302]

it is fuel injected. 190 pump, 19lb injectors, stock fpr. its the gauge on the cluster, i know these gauges tend to not always work. oil pressure used to be about 3/4s to up on the gauge and once i pulled out into the road i had absolutely no power, just enough to get up to speed limit, and i looked at the gauge and is was down to a 1/4. as rpms go up the oil pressure goes up but only by a little.

 

[stangbang302]

i forgot to add that, the gas in the oil i dont think is to much but you can definitely smell the gas and it feels really thin.

 

[stangbang302]

so im pretty convinced from research that i should replace my oil pump. but for the gas being in the oil, i think thats coming from cranking the car for so long just to get it started when its warm. but i dont know what to do about about fixing the long cranking part.

 

[SScott]

Before you do anything, change the oil. If you think that all the gas is from it not cranking then maybe the oil is so thin and the viscosity is too low to maintain pressure. I would try new oil first. If that doesn't work you can try the oil pump. I had the same issue on a new motor I bought off eBay, it was a clearance issue in all the bearings. I hope you get it going.

 

[stangbang302]

any suggestions on a good oil weight to use? i have 5w-20 but im pretty sure that oil is a little to thin.

 

[SScott]

Man that question will get a lot of different responses. I always use Valvoline 10-30 in everything.

 

[stykthyn]

5w-30 or 10w-30

 

[90mustangGT]

My first thought about the gas in oil is a stuck open injector. I am taking it for granted you don't have a misfire. A lot of fuel in the oil is a sign of a problem. Before you install a new oil pump (which I can almost promise you will be a waste of time) I would pull the plugs and see what is going on there to see if one is wet or different. If you have a fuel pressure gauge, see if the system holds pressure after shutoff. If not then you have a fuel leak, either the checkball in the pump or an injector is open. Then again, you could just have a shot motor but I would at least check to see if there is another issue.

I would not even start it on that fuel/oil mixture.

On a side note, I wouldn't use 20 weight oil on our cars. 0w20 and 5w20 is quite thin, especially when hot. It was designed for newer model cars with tighter clearances, and our cars, unless your engine was rebuilt with tighter clearances, probally could bennifit from thicker oil such as a 10W40, but a 20w50 may be a bit much unless you have a stronger than stock oil pump driveshaft.

 

[stangbang302]

alright so you were right, the oil pump did not go out. i started the car so i could pull it into the shop and it oil pressure was back at normal, so im thinkin its the gas thats mixed in the oil. i havent been able to work on the mustang yet, but tomorrow i have all day to do so. im gonna pick up a fuel pressure gauge and see if the car keeps pressure after i turn the key on. also im gonna do an oil change but not until i find the problem about the gas, what else could be the problem with when its warm it takes a lil while for it to fire up? i would hate to do an oil change and get the problem back. so i wanna keep my options up.

 

[mr_josh]

If you think that you're have to run the car at all to work on it, change your oil. Listen to 90mustangGT: running that mixture of fuel and oil through your motor is really asking for it. Very much gasoline in your oil will wipe out bearings right-quick.

Just go get some cheapo store-brand oil from your favorite parts house, do a quick oil change, figure out where the fuel problem is coming from, and when you do, do another change with a name-brand oil. You'll thank yourself later when you're not yanking the motor.