New Engine...Low Oil Pressure

[swathdiver]

Have this happening currently, had my engine replaced with a factory re-man @ 208,000. at that time also replaced exh. gaskets and seals,all hoses, water pump, thermostat, engine mounts, op sensor, starter, alternator, rad cap and ov flw tank, drv. belt, pulley and tensioner, plugs and wires, temp sensor, dipstick tube, and cam position sensor. whew!

Any how few months later, kept getting rough idle and low oil pressure at every stop but since I am a woman nobody believed me "Nothing Wrong , Normal" .
Forward 1 year later (not sure of the mileage here) still happening and 30 miles away from home I get a check engine lite and call onstar they say I'm ok to drive home and take to dealer... Now driving home on freeway 40 mph, in limp mode, in slow lane all the way ...

At dealer they check out and re-man engine was put together from plant wrong ( on a Friday lol ) So I get it newly rebuilt from dealer..

Now at 280,000+ miles over 4 years and out of warranty and still have this rough idle and low op at stops and STILL getting told this is normal... REALLY ! It runs fine at go. op at 40 but once stopped it immediately idles rough and op drops to about 25.

Anybody else have/had this issue and gotten it fixed?? New engines should NOT have this issue.

Kat, can you tell us what year, make and model and engine? 25 psi is not low oil pressure for an LS engine, especially if it is an aluminum engine. What are the rpms when it idles rough? I suppose it is in drive and stopped when it does this? Does it shudder like it's going to stall?

 

[KatGV]

Kat, can you tell us what year, make and model and engine? 25 psi is not low oil pressure for an LS engine, especially if it is an aluminum engine. What are the rpms when it idles rough? I suppose it is in drive and stopped when it does this? Does it shudder like it's going to stall?

It's a 2005 4WD 5.3-L V-8 OHV 16V. Idk what the rpms are when it does this, I'll reply back when I find out. Yes, it's in drive and stopped when it does this and if it weren't for the rough idle it wouldn't bother me, no it is not so rough that it seems like it will stall. I know how it runs when we first got it, it ran flawlessly up until right before we replaced the engine once replaced (for a few months) and then rebuilt after (for a few months) it did not do this? This is my daily driver and we also use it at least once a month traveling from Cali to AZ. So my baby is driven hard but it is taken care of and serviced regularly by a dealership.

 

[KatGV]

It's a 2005 4WD 5.3-L V-8 OHV 16V. Idk what the rpms are when it does this, I'll reply back when I find out. Yes, it's in drive and stopped when it does this and if it weren't for the rough idle it wouldn't bother me, no it is not so rough that it seems like it will stall. I know how it runs when we first got it, it ran flawlessly up until right before we replaced the engine once replaced (for a few months) and then rebuilt after (for a few months) it did not do this? This is my daily driver and we also use it at least once a month traveling from Cali to AZ. So my baby is driven hard but it is taken care of and serviced regularly by a dealership.

swathdiver I remebered to check on the way home today the rpms are at 500 when it's low pressure and idles rough thx Kat

 

[swathdiver]

swathdiver I remebered to check on the way home today the rpms are at 500 when it's low pressure and idles rough thx Kat

I think that's too low Kat. Should be at least 550 if memory serves. My tuner raised mine a hair to combat what you're experiencing. Now, how do you fix it?

I'll let the guys chime in here with solutions and will reply later if necessary, time for some shut eye before work tonight

 

[tjoyce81]

The most likely cause of a low oil pressure issue in a 5.3 is a blocked oil pressure unit screen or an oil pump o-ring failure. HOWEVER - there is an often overlooked and very common issue that puts many of these engines in the junkyard FOR NO REASON. It is a weak or failing oil pressure relief valve inside of the oil pan. If ALL of the above does not fix the oil pressure issue - it IS the relief valve inside of the oil pan. The spring wears out in these valves, which causes oil to simply dump into the pan - and not feed the upper part of the lifter feed circuit. The oil pressure sending unit is located in this circuit - which is the reason you get a low oil pressure indication - when in fact oil pressure is good. The fix is to either replace this valve, or to simply install a plug so the oil does not dump into the pan.... When you block this off - oil pressure will be better than before....

 

[Miami-Dade]

I ended up selling the Yukon. I lost about $6,000.00 when it was all said and done but have learned my lesson. Originally the engine shop said they would give me a full refund but then backtracked and said they wanted the good parts of the motor back. So in turn I would have to pay someone to pull the motor, send it back to Michigan and wait for my refund check to arrive. At this point I was already out so much that I sold it for cheap to be done with it.

Never ever do business with accurate engines out of Wyoming, MI. I have never been treated so poorly or lied to so blatantly in my life.

Just read all this. Just awful Greg.

I am sure everyone here has made really bad decisions through the years so do not beat yourself up anymore over this.

 

[Bigkevschopshop]

swathdiver I remebered to check on the way home today the rpms are at 500 when it's low pressure and idles rough thx Kat

Kat,
the low idle speed is probably pushing the limits of how low the pump can spin and make pressure. I have the same thing happen to mine once a week or 2...It just gets a hiccup in its computer, starts acting like it wants to die, 2 seconds later all fine like nothing happened.. ALso the LS series engines are not the smoothest motors on the planet for sure, they always are a bit rough, sometimes a fuel injector being a bit gummed will do it, I try to run a cleaner through mine as preventative measure once a month, and after the cleaner the idle drop thing goes away for a few weeks to sometimes over a month.

This fuel we have these days is crap anyways, so sometimes you are getting bad blends.

Does is to better after your long trip on the freeway runs or worse?

A simple throttle body cleaning may help too.

Fuel system cleaner that actually works is the Royal Purple Max Atomizer, only one that makes mine idle smooth enough I barely feel it when its in the tank.

 

[Summajet]

Here are some questions I would ask shop that rebuilt it,
1. oil pressure checked with mechanical gauge?
2. oil galley barbell put back in rear of motor? New? brand?
3.Camshaft thrust plate replaced with new one?
4. Oil Pump, new? Brand?
5. Oil pickup tube O-ring new? Brand

While they state they had incorrect camshaft bearings installed, that would affect the camshaft not properly getting oil and can damage the camshaft. items 1-5 is what I would ask the shop as these would affect the oil pressure.
I suspect they did not replace the oil galley barbell or totally forgot to put it back in. If let out it will push the oil on backside against the rear camshaft cover and not redirect it backside through the rear block and thus loose oil pressure.