oil pressure

Reply Subscribe

Thread Tools

Search this Thread

Mar 20, 2009 | 03:07 AM

aaronlockhart

Thread Starter

Senior User

Joined: Mar 2007

Posts: 193

Likes: 0

From: Biloxi, MS

oil pressure

This truck has an aftermarket oil pressure gauge, and when the engine is idling it maintains about 45 - 50 psi, when running I think I saw it get all the way down to 35. This isn't normal is it? I've never had an oil pressure gauge with actual figures on it, I just used to look at the one in my 95 and make sure it was somewhere in between "O" and "R" in "normal", lol.

Its dark out now obviously, but in the morning I'm going to check for oil leaks, I'm not 100% sure about this thing yet... The engine dipstick came off the block the day I got it home so I'm going to make sure its wedged in there tight enough that the oil isn't squirting out around it, and check my new valve cover gaskets and make sure they aren't leaking...

As I said, it was dark so I couldn't see any blue smoke or anything like that if the pressure was low. Had to take it around the block once tonight; the insurance kicked in at 12:01 AM, haha.

After this I can figure out what the hell is up with the brakes lol.

Mar 20, 2009 | 10:08 AM

Franklin2

Moderator

Joined: Jan 2001

Posts: 57,012

Likes: 2,750

From: Virginia

Oil leaks and blue smoke will not make the pressure go down. The oil pressure comes from the pump, and the resistance it sees when it pumps oil to the bearings in the engine. So a worn oil pump or bearings will cause low oil pressure.

It sounds like you started it up, and it had high oil pressure because the oil was cold. As the oil warms up, the pressure will go down because the oil gets thinner. This is normal.

The rule of thumb is 10 psi per 1000 rpm. If yours is higher, then your engine has less wear. If your engine is lower, than it has more wear. If it's little low, but not making any noises, don't worry about it too much. If it's low, and making noises, then start thinking about your options.

Mar 20, 2009 | 10:29 AM

82-100

Senior User

Joined: Dec 2008

Posts: 294

Likes: 0

From: East Bernstadt, Ky

what weight of oil do you use..i run 20w-50 in mine cause i had low oil pressure and now i runs smooth as a top

Mar 20, 2009 | 01:47 PM

aaronlockhart

Thread Starter

Senior User

Joined: Mar 2007

Posts: 193

Likes: 0

From: Biloxi, MS

Thanks y'all...

And I'm running 10w 40 in this truck, but yeah, I've heard of the heavier oil trick, and I'm pretty sure thats all those oil supplements, like Motor Honey, aren't really any different from heavier weight oil....

Glad I brought it up...

Mar 20, 2009 | 09:28 PM

1 F150dude

Senior User

Joined: Mar 2009

Posts: 370

Likes: 0

From: Diboll, Tx.

Heavier oil does not make you have better pressure. When was the oil changed last? If the oil has broken down then it will do everything you described. The manufacturer recomends an oil weight for a reason. They have tested several oil weights to find the best one for your truck, for your local temperature range. A bottle of Lucas will help prevent oil break down.

Mar 21, 2009 | 08:54 AM

Freaksh0w

Elder User

Joined: Jan 2009

Posts: 774

Likes: 1

From: East Tennessee

I used to like Lucas until I saw a VOA of it. It turns a 10W-30 into something like a 30W-70 or 80 (that's if you mix 1 quart with 5 quarts of oil) and it has absolutely NO additives in it, so it really makes your oil weaker. Want a thicker oil, get a thicker oil.

But, I don't see the problem. You are driving and the engine gets 30 psi. Nothing wrong with that, unless you are at 4k+ RPM.

Mar 21, 2009 | 10:22 AM

Franklin2

Moderator

Joined: Jan 2001

Posts: 57,012

Likes: 2,750

From: Virginia

Thicker oil will give you more pressure, but there is a debate as to the benefit besides making the gauge read higher. I have had older engines, and have used 20w-50, and it did give me about 5lbs more pressure, but it still seemed to burn the same amount of oil.

Speaking of which, that is another indicator of the condition of the engine. If your engine has a lot of miles, pressure is a little low, makes some noises when you first start it up, and uses a little bit of oil, those are all indicators the engine has some wear, and in that case I would not go in and try to do surgery and replace a oil pump or some bearings in the bottom end, when the rest of the engine needs work too. I usually just drive them, keeping oil in them till I get the money to get another engine, or the time to rebuild the one I have.