Oil pressure low when idling

[Jbro238]

Well I got charged for an hour and a half of labor. An HOUR AND A HALF. so you think they would have found that. But I'll try it anyways.

[Jbro238]

Oil pressure is doing better with added conditioner
Any more thoughts?

[myfirstbonnie]

IMHO, I would buy a new sender and replace it and see what it does. I have seen them fail both ways (high and low).

Also, what Don was trying to say was to remove the cap where you pour the new oil in. Then using a flashlight, look in there while the engine is running and see if there is oil pooled in the corners and edge towards the front of the car. This will tell you if you are at least getting oil to the valves and lifters.

I agree, if you had 0 oil pressure, that thing would sound like a bunch of bolts in a blender from lifters not pumping up.

[nos4blood70]

+1 on the sender replacement. It will tell you a lot, as mentioned they usually peg when they fail, but can go both ways.

[Jbro238]

That's multiple people saying that so I will do it! I just don't understand how the shop told me it was reading correctly if they used their own tool thing hah

[nos4blood70]

Did they say whether they used a mechanical gauge to measure actual pressure?

[MattStrike]

Is this the first oil change since you bought the car?

[Jbro238]

Yes they used a mechanic al. Gauge to check the car. Said it was reading correctly. With low pressure.

And yes I bought the car 3 months ago and just got the first oil change
My theory here is the owner before me put in a thicker oil and when they put a normal in it then it wasn't enough. I don't know

[MattStrike]

Your symptoms fit a bearing clearance problem. You should not run the car without at least 10psi showing up at idle. My guess is that the previous owner was using 20w50 or maybe maybe something heavier to hide the problem and sell the car.
I recommend that you drain the oil and switch to 5w40 or thicker. The goal is to get the oil pressure up to 10psi at idle, but either way you are on borrowed time. I'd start saving up for either a replacement or rebuild.

If you have the tools, I would plastigage the main and rod bearings, this lets you get a look at them to see if any are going bad as well as letting you know if the problem is a crankshaft bearing or a cam/balance shaft bearing that can be fixed before there is a failure, or if the failure has already occurred and needs a rebuild. I don't know what the going rate is for a shop to do that for you. But you don't need to pull the motor to check the crank bearings.

[Jbro238]

I did drive the car 2000+ miles this summer and had no problems tho. Wouldn't that have shown up during the summer?

[MattStrike]

It made it 2000 miles on oil that was maintaining pressure. Even if this is an issue where the failure only just happened, not a product of someone looking to unload the car before it goes, it doesn't change my recommendation. It needs oil pressure to maintain the oil film at idle, absolute minimum is 10psi @ hot idle. If you don't have pressure, it will continue to wear the bearing until it grinds the crank or spin a bearing or sieze the crank. Ask me how I know... For all we know somebody put gear oil in and that's why the lifters aren't draining down/clattering.

However, the point about the plastigage, is if the bearings are just worn down but the crank has not been damaged yet, you can replace the crank bearings now without costly machine work as long as the new bearings gauge good too. But if it's a cam bearing or the balance shaft bearing the engine would have to be disassembled to replace them. Worst case scenario you find that a bearing had already spun, the previous owner put a new bearing in with heavier oil to hide it, and you need a rebuild anyway. Best case you find a main bearing that's almost gone, but no crank damage, and you can put in new bearings.

[Jbro238]

Looks like I'm heading back to a new mechanic. Hm.

[Jbro238]

well. here we go guys. just stumbled upon the receipt from the valvoline place. they put 5w30 oil in, not 10w30 like it calls for. that would be the cause of my problem. will change the oil to the CORRECT weight tommorrow

[nos4blood70]

5W30 would not change much of anything.

[Jfridge92]

The first number, the 5w, is mainly for when the car is cold. In colder climates, you'll want a lower starting number since the oil will flow easier when cold. The 30 indicates how viscous the oil will be once the motor is warm, so once the engine is to temp, 5w30 and 10w30 will behave almost the same. If it was a 5w20, that could definitely make a difference, although I'm not sure how much, but I run 5w30, when it's cheaper and have no issues.

[Arrowhead]

Whatever is printed on your receipt doesn't mean that that's what the min. wage goober in the service bay actually poured. I haven't trusted anyone but myself to do my brakes or oil changes since I was 17 years old. There's no room for errors or tricks that way, IMO. JiffyLube and similar outfits used to be inexpensive, they're not anymore, particularly if they manage to cause damage which is very frequent nowadays. Do yourself a favor and get set up to change your own oil.

[Jbro238]

well we will find out tommorrow. ill be switching out for the correct oil and i think itll solve my problem. cuz its barely in the red. on the gauge.

[Jbro238]

did a complete oil change and put in 10w40 and still am in the red for oil pressure. will be taking it to a new shop today so get it more checked out. im ordering a sensor online today i will be replacing it this week