Newtothiss

Just had a rebuild on an ls2 V. Before the rebuild a new pump was installed that would read low oil pressure around 10psi when hot and 25 when driving.

Now that the motor has been rebuilt (stock everything) except .020 pistons it is still reading 16-17psi idling (will eventually go down to 13 idling) and 27-31psi when driving. It was reading around 25 while driving but changed the oil then went up to 30 after driving it for 200 miles. According to the mechanic it was suppose to go up as everything broke in but I don't think that's right.

Maybe a wrong o-ring? The same exact brand pumps were used now and before rebuild which is why I think maybe it could be the wrong size o-ring.

442scotty

The first thing I would do is check the pressure sensor to see if its reading correctly..

Newtothiss

Oh yes forgot. Changed the pressure sensor. Old and new read exactly the same.

Mercier

iTrader: (15)

None of this sounds good. Oil pressure will not rise as an engine breaks in from my experience. At least not double or more which is what I would need to be comfortable. Check it with a mechanical gauge.

Could be wrong or damaged o-ring, loose clearances, etc. O-ring probably easiest to check but mechanical gauge first IMO.

Did you use the same pump post-rebuild? Pump could be bad or wrong/dirty bypass spring/orifice as well.

Newtothiss

Ok I'll try to check it with a mechanical gauge. Different pumps but both same brand which is why I'm thinking it has to do with the pump/o-ring (maybe wrong o-ring). My old one gave out, so I replace it with a new one but it never read as high as the stock one.

Now on the rebuild this new pump is doing the exact same thing that the first replacement was doing. It's a sealed power oil pump from rockauto.

Mercier

iTrader: (15)

I've no experience with their pumps personally. Melling and GM only so I can't comment on quality or fitment. What was the impetus for rebuild?

Newtothiss

Oh ok I probably should have went with a Melling. Lifters went out causing other headaches.

Naf

iTrader: (1)

I exclusively buy katech oil pumps...

Newtothiss

Can I use the autometer adapter for the mechanical gauge?

http://shop.advanceautoparts.com/p/a...FQRehgodL5EEuw

Mercier

iTrader: (15)

Yes. Summit seems to concur. I used one of these but had to check to make sure I had the right part#:

https://www.summitracing.com/parts/ATM-2268/

Newtothiss

Awesome, I'll give it a try! Thanks

bigti99a

iTrader: (16)

Maybe bad ground causing low reading. Check with mechanical gauge then go from there. Hope you don't have to tear too far into it.

Newtothiss

I ordered the adapter for the mechanical gauge today. I'll check grounds as well. When my oem one went out I replaced it and it never read like the oem one did. Then the motor was rebuilt and once again it's reading the same. I just feel like the chance of both replacement oil pumps being bad is just way too low, but I mean it's the only thing that makes sense since both were the same exact brand and both read exactly the same.

I almost want to just go ahead and order an oem one from tasca parts but I'm gonna wait to check it with the gauge first. Thanks I hope I don't have to either!