Low oil pressure

Syty84

Donating Member
I just put in a new build, vortecs, forged pistons, stock crank, mellin high flow pump, etc when i first fired the motor up oil pressure seemed pretty high which is always does on my truck at about 70lbs at idle but i know the gauge can be off a bit, after that i drove it around and it always seemed to stay around 70lbs.

I changed the oil after about 10 miles of driving, now it still reads high when i start the truck but after driving it around for a bit and i come to a stop or idle the gauge it showing about 40lbs, and since the motor is quieter I can hear it sounds like its low on oil. Not sure what to do, I have plenty of oil (double checked that), I have a small leak behind the block but nothing major and when I drive it around, the gauge goes back up to 70lbs or so. Out of all the builds i've put into my trucks, this is the first time I've had this issue. I always use the same engine builder as well. I really dont want to pull the motor as I've spent the last 3 days putting it in. :rant:
 

pearl91chevy

Donating Member
Re: Low oil pressue

Re: Low oil pressue

That sounds like normal oil pressure to me.. My oil pressure is always higher when I first start the truck cold.
 

ajt86

Member
Re: Low oil pressue

Re: Low oil pressue

My 100k mile ty is 70 at idle cold... 18psi idle hot in gear. On a 4.3 anything over 10psi, engine hot, in gear is sufficient
 

Syty84

Donating Member
Re: Low oil pressue

Re: Low oil pressue

Thanks for quick reply's it's going to be dyno tuned this week so I'm just run with it, I'll post videos and dyno sheets, it's basically the same build Nolan tuned a while back that put out over 500hp on a 60-1 hybrid turbo, but I have vortecs and a FAST XFI, should turn out well.
 

Don W.

Stab it and steer it
Re: Low oil pressue

Re: Low oil pressue

Idle oil pressure not a big deal. I wouldn't like 10# but 20 would be good. Regardless are you using a real gauge or the panel gauge? I wouldn't trust the panel gauge out the garage door. My real gauge reads 50 off idle with the oil hot.

Also what grade of oil are you running?

When you say it sounds like it's low on oil that is concerning. What sound are talking about? Or we'll wait for the vid.
 

Syty84

Donating Member
Re: Low oil pressue

Re: Low oil pressue

For ex. our company has an astro van has a 4.3 in it and no one bothered to check the oil for the last 4 months, so it was running really low, I could tell when I drove it because the motor sounded louder especially if i was parked on a hill, I checked the dipstick and the oil mark was under the low oil line, I added two quarts or so and the noise is gone, well my engine at idle sounds very similar to this one when it had low oil, I'm running 5w-30 conventional but about to switch to full synthetic, like I said I've never seen my gauge this low ever, I'm only basing this on the stock cluster gauge, I would like to get a digital oil pressure gauge just dont have the funds yet.
 

Sportmachines

Active member
Re: Low oil pressue

Re: Low oil pressue

You could also test it with a mechanical gauge pretty easily at the remote oil filter block on the fender. That way you can verify it pretty quickly. HTH
 

johnboy89

Member
Re: Low oil pressue

Re: Low oil pressue

What you are experiencing on the stock gage is exactly what I see and seems normal. Mine did drop some after the so called break in, but stayed there afterwards.

My concern is the noise like you said, to be safe I would try and borrow or somehow hook up a gage to verify. The gage could be off quite a bit and you do indeed have low oil psi???
 

Don W.

Stab it and steer it
Re: Low oil pressue

Re: Low oil pressue

A mechanical oil pres gauge is inexpensive. Get rid of the 5w oil. 10w-30 min, 10w-40 better. I run 20w-50 racing. Just to be on the safe side cut the oil filter and examine carefully. :2cents: Again
 

T-Bone

Active member
Re: Low oil pressue

Re: Low oil pressue

I would like to get a digital oil pressure gauge just dont have the funds yet.

I would NOT put this truck on a dyno given your concern and what you heard. Way too risky and if you don't have the funds for a gauge, potential near term internal (costly) engine repairs are out of the question.

As others have suggested, check the oil pressure manually first. All the best.
 

atkonkler

Is this your bush?
Re: Low oil pressue

Re: Low oil pressue

What about a 40 or 50 weight ? Too thick?Obviously not in below 32degrees but say in the summer time?
 

ajt86

Member
Re: Low oil pressue

Re: Low oil pressue

checking the oil pressure at the remote filter is easy with the port on the side- just make sure you have the right adapter in the kit you buy to thread in- its a large hole- most gauges are made for checking at a pressure sensor wich has a much smaller hole. I think its 3/8ths but im not 100% sure

I was freaking out after I bought my ty- the needle would sit in the red at hot idle, someone did white face gauges on it and apparently guessed where the needle went.
 

Don W.

Stab it and steer it
Re: Low oil pressue

Re: Low oil pressue

I forgot to look at where you live. Dave's correct. Straight 30 would be fine. If you can find it. Depending on the characteristics of the noise you might be hearing "piston slap." Does it tend to go away with the motor fully warmed up? Also valve gear can make funny noises.
 
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