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Old 02-28-2017, 10:04 PM   #1
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Default LS6 no oil pressure

02 Z06, ~70k miles on the motor. Cam installed about 40,000 miles ago. Been running without any issues since. Drove to/from work today without any problems, about 20 minutes each way. When I left the gym this evening I got a low oil pressure warning briefly, was seeing 22 PSI at idle, and 40-50 PSI when revved, oil temp around 180 degrees. Drove it home, like 1-2 minute drive. 2 hours later, started the car and it's showing 0 psi oil pressure. Ran it for about 10 seconds, never showed any oil pressure at all. Don't hear any unusual sounds. Haven't drained oil or pulled valve covers or anything yet, just wanted some suggestions on how to approach this. I'm thinking first I pull plugs and valve covers, and crank to see if it's pumping oil? If so, then probably a sensor issue? If no oil hitting the rockers then maybe a failed oil pump?
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Old 03-01-2017, 08:29 AM   #2
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If showing zero pressure yet no lifter noise, the oil pressure sender might be suspect. Change it before starting again. If still no pressure shown, there is a problem.
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Old 03-01-2017, 08:58 AM   #3
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Put a mechanical gauge on it or replace the OPSU and see if that fixes it. Those sending units go bad.
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Old 03-01-2017, 09:03 AM   #4
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Put a mechanical gauge on it or replace the OPSU and see if that fixes it. Those sending units go bad.
Good call using a mech. gauge first. Must be too early in the AM for me.....
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Old 03-01-2017, 12:25 PM   #5
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Going to try a mechanical gauge at the oil temp sensor location and go from there. Hopefully just a broke sending unit but I think those usually show max pressure when they fail.

Anyone know thread size I need for the mechanical gauge ?
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Old 03-01-2017, 01:47 PM   #6
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Going to try a mechanical gauge at the oil temp sensor location and go from there. Hopefully just a broke sending unit but I think those usually show max pressure when they fail.

Anyone know thread size I need for the mechanical gauge ?
I would imagine AutoMeter does.
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Old 03-01-2017, 02:55 PM   #7
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Found it - M12 x 1.5. going to drop by harbor freight on the way home today and buy this pressure gauge. http://m.harborfreight.com/engine-oil-pressure-test-kit-62621.html

​​​​​​If I'm not seeing oil pressure with a mechanical gauge, next step is oil pump replacement?
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Old 03-01-2017, 05:01 PM   #8
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Yeah; pump work of some sort. IMO, unlikely you went from 20-50 to zero by /breaking/ the oil pump(without some fun audio to match); if pump I would guess the bypass stuck open.
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Old 03-01-2017, 06:23 PM   #9
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Hooked up a mechanical gauge where the oil temp sensor by the oil filter - no pressure. Started the car for like 3-4 seconds to see if maybe that would do anything, nope. But still no unusual engine noises. I cut open the oil filter and didn't see any metal shavings.

So all signs point to an faulty pump? Any chance it could be like a clogged/failed oil filter?

Last edited by onspeed; 03-01-2017 at 06:43 PM.
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Old 03-01-2017, 06:30 PM   #10
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I think only if the oil filter failed to the point where the oil vented to the atmosphere would you get this result. There are truly remote possibilities like the barbell blowing out the back of the block or the pickup tube falling off or similar, but you're hearing what it is 99% of the time.

That being said, have you checked the oil level to ensure you have a full pan?
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Old 03-01-2017, 06:41 PM   #11
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I think only if the oil filter failed to the point where the oil vented to the atmosphere would you get this result. There are truly remote possibilities like the barbell blowing out the back of the block or the pickup tube falling off or similar, but you're hearing what it is 99% of the time.

That being said, have you checked the oil level to ensure you have a full pan?
Oil level was good. With no knocking or lifter noises and no metal debris in the filter, there should be a good chance that I can get away with just replacing the pump and avoiding a rebuild yeah?

Now to decide stock LS6 vs TSP ported. Anything else to do while I'm in there? I think I'll change my UDP back to stock size and pin the crank so I can go FI in the future. I didn't touch the timing chain when I did the cam as the engine was a crate motor that already had the upgraded ls2 chain.
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Old 03-02-2017, 11:04 AM   #12
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My shopping list at the moment:

-Melling 10295 oil pump - should come with new pickup o ring?
-front cover gasket and front main seal (replaced these when I did the cam - do I need to replace again?)
-oil pan gasket
-Powerbond PB1117SS (stock sized crank pulley - switching out my 25%UDP in preparation for an s/c build)
-a&a crank pin kit
-coolant/oil/etc.

Anything I'm forgetting? Water pump is relatively new, car already has PatG cam.

edit - any chance this all could be due to a collapsed lifter? Perhaps I should pull the cam when I have the front cover off to look for any damaged lobes?

Last edited by onspeed; 03-02-2017 at 11:34 AM.
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Old 03-02-2017, 01:41 PM   #13
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The new pump should come with o-rings. If the front cover gasket and main seal look good, reuse. They are designed that way. Don't forget a dab of black RTV in the corners at the pan.

Not sure about the Vette, but I've changed the oil pump without taking the pan off. YMMV.

Anything is possible but I would think any issue outside of the pump wouldn't cause 0 oil pressure. Low pressure, perhaps. 0? IDK.

Tell me again where you connected the mechanical pump?
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Old 03-02-2017, 03:23 PM   #14
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Connected oil pressure gauge here:



On the C5 that hole is threaded and an oil temp sensor plugs in there. I just removed the temp sensor, plugged in my HF gauge and cranked the car. Needle didn't move. Started the car for couple seconds, same thing. No oil in the gauge tube either when I took it off.

On reading some things I think you can leave the pan on with the C5s. I think F-body might need the pan dropped a little.

Just seems odd the way the pump failed, I figure I would see consistently low pressure for a while rather than just dying like this. Don't want to go through the work of an oil pump change just to find out it's like a collapsed lifter or something and have to essentially tear everything apart again. Pay to play though I suppose.
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Old 03-02-2017, 03:57 PM   #15
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OK; you did it right. Just asking the stupid questions before you get everything torn apart.

I agree that good pressure to zero is not the usual. But the usual is also good oil pressure.

​​​​​This is why I suspect the bypass. On the LS it isn't a ball and spring like on older designs; it is a sort of sleeve in a hole and seems more prone to binding.

Possible your oil pump bolts backed out and it is not sealing to the block properly?

At any rate, it sounds to me like an adventure in the front cover is in your future.
​​​​​​
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Old 03-02-2017, 05:12 PM   #16
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Quote:
Originally Posted by Mercier View Post
OK; you did it right. Just asking the stupid questions before you get everything torn apart.

I agree that good pressure to zero is not the usual. But the usual is also good oil pressure.

​​​​​This is why I suspect the bypass. On the LS it isn't a ball and spring like on older designs; it is a sort of sleeve in a hole and seems more prone to binding.

Possible your oil pump bolts backed out and it is not sealing to the block properly?

At any rate, it sounds to me like an adventure in the front cover is in your future.
​​​​​​
Honestly didn't touch the pump when I did the cam since I figured everything was relatively new. Cam went in 2011, motor was replaced in 2009 I think. I'll get to tearing it apart this weekend. I guess I'll find out what the culprit was when everything is put back together again.
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Old 03-03-2017, 03:55 PM   #17
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Most likely the bypass valve is stuck open.
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Old 03-13-2017, 06:11 PM   #18
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Looks like bypass valve was stuck open.

Shouldn't be a problem to crank the motor once I get the balancer and front cover back on? Make sure I have oil pressure before reinstalling the steering rack, radiator, etc?
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Old 03-13-2017, 06:59 PM   #19
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Quote:
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Looks like bypass valve was stuck open.

Shouldn't be a problem to crank the motor once I get the balancer and front cover back on? Make sure I have oil pressure before reinstalling the steering rack, radiator, etc?
This makes me glad the Schumann's pump I am going to is back to the good old check ball. I'd like to hear the engineers' reasoning by changing the tried and true design from many years past.

I don't see why not; it should build oil pressure without any of the accessories(and leave those disconnected if the rack is disconnected of course). Since you have run it a few times with no oil pressure and you have the adapter for the mech pump, you may consider getting yourself a cheapie garden sprayer and rigging up an oil primer. My buddy Steve(05CTSV here) says he did just that with nothing special and filled his engine with oil that way. Basically you drain the oil and use the sprayer to "fill(prime)" the engine with the proper amount of oil. Occurs to me turning the engine by hand a couple of times during this would help get things flowing to the right places.

Perhaps I am being overly cautious but an option for you.

Good luck!
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Old 03-13-2017, 07:08 PM   #20
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Was going to just fill the pump the way Melling recommends in this video:


and crank away with all the accessories, plugs, and etc off until I started seeing pressure on my mechanical gauge. Haven't read of anyone doing this before, although I have seen some posts where people have everything back together just to figure out that the o-ring wasn't sealing correctly or something.
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