took my car out today and got my annoying rattle i get when taking off pretty hard from a start and noticed idling in gear my oil pressure jumping around from 20 to 25 psi. around 38 to 40 cruisin. ive bben trying to figure out whats making the sound for a long time it hasnt been beat on and has 50000 miles on it then i found out when i was out of town a while back my girlfriend took it to walmart and had 5w30 pennzoil junk put in it. i think thats my prob i dont remember the sound before the junk went in what do you guys think? next day its warm im putting castrol 5w50 in screw that light stuff. i think that junk must be totally worthless once the car gets warm. anyone else ever heard of this or am i nuts?

 

i have never heard of oil causing that.. but i guess theres always a first time for everything i guess if i were you id switch back to your regular stuff and see if that solves the problem.. is the car throwing any codes at all??

 

Firts, I wouldn't put 5w 50 in, 5w 30 is recommended and should be more than enough viscosity. Remember too that if they changed the oil they changed the filter and who knows what that is. I would change both asap.

 

no it isnt throwing any codes. it runs like a scalded dog. it makes that sound on a strong take off like a mettallic rattle then stops or i dont hear it. i never remember my pressure being that low and thats when it makes the sound idling in gear at 20-22psi and taking off. i think that pennzoil junk is to light or something because when the oil is coolish say at 40psi i dont remember the sound happening only when it gets warm and has been around the low 20's. im going to try the 5w50 i figure it cant hurt it will flow good cold and be alright hot. i guess ill find out soon plus i need to change my plugs.

 

well i changed my oil today and put in the 5w50. ran the car and think that was wehat it was. if i punched it i had 60 psi idling in gear it never got below around 43 i thought i might have heard a faint buzzing sound once or twice3 but it was nothing compared to that rattle that sounded like something was going through the hood. maybe ill be able to get rid of some of the other noises when i change the plugs and fuel filter. anybody else ever go through this? i didnt find really anything in my oil and the magnet on the plug basically gave me a couple dark smears so fine i could feel no grit. i never paid attention but is that normal?

 

Does it sound like marbles or nails ratting around in a tin can? If so that's detonation. It could or could not be related to your oil. If it is related to your 5w30 oil I'd assume the thin weight oil allowed some oil to come through your PCV valve and into your motor and contaminate the air/fuel mix. Detonation is usually caused by running lean, bad or improper fuel, or long term oil contamination that fouls out the spark plugs though.

 

yea that basically is what it is. it would happen when i punch it prtetty hard thwen settles down. ive heard it slightly once or twice since i changed the oil but the car is much quieter. i also put some good gas in since she put in 87 a while back. you guys think my plugs might be a cause too? my girlfriends car gets kinda noisy when the plugs need changed sort of like mine. new plugs and fuel filter hopefully take care of it. thanks guys and oh yea how the hell do you change the rear spark plugs from underneath? i could barely see them