New Engine Losing Oil Pressure

[Lance Butler]

I just finished reinstalling my engine. I chose to have it rebuilt by a local shop (Knighton's Automotive machining in Albuquerque). I spent the time to pull it myself and reinstall it myself.

On the initial start I find I am losing oil pressure. Yes, I am using the stock oil pressure switch from OBDII rather than a proper oil pressure gauge. That is why I am posting here in the flame free zone as I am not in the market for information about why I should put in a real oil pressure gauge.

I took videos of each time I cranked it so I could go back through the gauges and see what happened. It feels like it started fine and sounds good. After reviewing the videos I see the following:

I cranked it 4 times without starting it for 2, 3, 4 and 8 seconds respectively. Before and after each time I left the key in the on position to let the lift pump fill everything up. I added a fuel filter while I was doing this project so I don't go through another set of injectors, so I figured it needs time to fill.

After those 4 cranks (with nothing disabled) it fired up and oil pressure came right up. It ran for 37 seconds at idle and then lost oil pressure. I shut it off right away and checked fluids. Fluids are kind of tricky after a project this big as everything needs to fill various coolers and such so I started with everything overfilled. I added some coolant, some transmission fluid, and some to the power steering circuit. The engine oil still showed too high.

It has now run for 223 seconds and dropped oil pressure 3 times. Each time I shut it off and checked oil and for leaks. No issues.

Your thoughts are greatly appreciated.

I am trying to decide. Is this kind of normal with a new engine where the oil is going all kinds of places and needs to fill things up. Or, is this a bad sign and I need to stop and call the engine builder and scream?

I insisted on a genuine Cummins oil pump rather than the standard aftermarket one they normally use.

Truck is a 2006 4X4 Dually, quad cab, automatic. 120,000 miles. The first 30,000 I put on her were rough as I did not understand about diesels and maintenance. I learned better a few years ago, but the new engine is me paying the bill for my previous ignorance.

Thanks.

 

[JR]

You simply can NOT trust the OE sender for accurate oil psi. Screw in a manual gauge - even if it is one in the engine bay that someone watches while you start - and compare results.

 

[TFucili]

If it's not a gauge/wiring issue, I'd be thinking about the relief valve. Was it replaced? Loose oil pickup?

 

[cerberusiam]

No that is not normal, you should have oil pressure almost immediately and it should stay high cold idle. Put a manual gauge on it to verify before doing anything else, make sure you have the right sender unit. Happened to me on a 6.1 hemi when someone did not get the correct sending unit installed. Always verify with a manual gauge before digging deeper.

 

[petersonj]

Yes, I am using the stock oil pressure switch from OBDII rather than a proper oil pressure gauge. That is why I am posting here in the flame free zone as I am not in the market for information about why I should put in a real oil pressure gauge.

You may not be in "flame free zone" here. If were in your shoes and the moment I saw the OBDII reader reporting that I was losing engine oil pressure I would immediately stop everything and put in a mechanical gauge - like NOW! I would want to know absolutely what is happening with the lubricating system. Others are telling you the same thing.

- John

 

[Lance Butler]

Autozone oil pressure gauge: $105. Various fittings and nipples from Lowe's in 1/8" NPT to get it to fit: $23.

Oil pressure gauge from Autozone showed just about zero. I reved it a bit to see and that did not help. All in this time with idle, then rev, then idle was 32 seconds before stock oil pressure switch dinged and I shut it off. As a bonus, when I shut it off this time I heard a rattle that sounded a lot like a turbo. I think this no oil pressure situation burned my turbo.

The pressure is so low it is hard to estimate what the gauge was reading. I videoed it. I estimate it says about 6 PSI.

Less than 4.5 minutes on my new engine and apparently I need an engine... and a turbo. At least it is Memorial Day tomorrow so I can't go postal on this engine builder for 24 hours.

 

[Lance Butler]

By the way, John, yes that was my first thought. So I posted my query, then got my wife to drive me around to find a gauge on Sunday night before a holiday.

So, I guess there isn't much you guys can help with. It must be that something went wrong with the engine build. The problem is that they will pretty much need to pull the engine to sort it out. While it is under warranty, I put way too much time into installing it to let whatever shop the builder uses touch it. Everything is pristine clean, every wire is right, every radiator fin is straight, every fluid is high end, every bolt is torqued right. So, I will have to pull it for them, install it back when I get it back and have them pay me whatever they would pay some shop and argue the whole time to get it done. To top it off, my truck has been down for a couple months for this and I have a big motorcycle race in two weeks and I need my fifth wheel.

I need an upgrade. To the word "frustrated". Frustrated just doesn't get it. "Homicidal" is close, but I probably shouldn't post that on the interwebs in front of God and everyone in case they use it in court against me.

I guess I'll just go watch my recording of the Monte Carlo F1 race and then the Indy 500 and maybe tomorrow will be better...

 

[Ozymandias]

If the turbo wasn't flushed with brake kleen prior to install then it shouldn't be hurt from a couple second idling.
There is always enough residue oil in it for a startup.
It doesn't spool up and it isn't hot then.

First i would check if the oilpump even flows oil, that can be done by unscrewing the 1/8npt plug on top of the filter housing, filter the first inline after the pump, but just crank it - dont start it, after a couple seconds of cranking you should see a fair amount of oil coming from the filters base.
You can also check pressure at that position.


Then i would check the oil pickup tube within the pan first, that can be done wile the engine is installed, just need to be lifted about 3" to give way to the oil pan away.
I just can't imagine something after the pump that looses so much oil to let the pressure fall to zero, the pump flows way more oil then that is usually needed for the regular circuit.

 

[TFucili]

I've seen engines assembled without galley plugs, but pretty unlikely.

 

[mwilson]

Did the engine builder install the base and sump or did you install the engine with base in place??

Wondering about loose sump or missing the sump gasket......

 

[AH64ID]

As you’ve noticed the ECM has a ~30 second delay for the low oil pressure indications.

Hopefully there is enough assembly lube on everything that nothing has been damaged. You can add some oil to the turbo via the feed line too.

What is the oil level?

 

[Lance Butler]

The engine came back to me complete from oil pan through valve cover.

Engine oil is a bit high as I expected the level to drop a bit once pressure ran oil to all the places it goes. I think I will drain a little out to get it perfect.

I guess we will see what the builder has to say tomorrow.

 

[Ozymandias]

Why drain oil?
That doesn't make sense at al right now.
Check if the pump flows oil or not - then go for side quests.

 

[jghflys]

At this point, the engine rebuilder should have the lead on steps to take. I would follow their lead. I pre-lube all rebuilds. Your engine builder should have a pre-lube tank. Get it and use it It connects at the oil filter block 1/8 NPT connection. Remember to isolate the oil tank before you run out of oil in the tank or you will blow air into the oil system. As soon as you are done with the pre-lube pull the hose and put the plug (or mechanical gauge) back in the filter block, then start the engine. The problem sounds like a suction problem on the oil pump. It is either dry or has an air leak on the suction.

 

[Lance Butler]

Update: I spoke to the builder. They are on about strike 6 with me. They said they never do the priming and never need to as oil pressure always comes right up. Keep in mind that this is an automotive machine shop. They do machining and also assemble long blocks. They do not install engines. They said they have never heard of this problem. They were at a loss as the owner is on vacation this week. They were stumped because I am doing the install myself. I think they wanted me to bring it to some shop to have them sort it out. I spent way too much time getting the details right when I put the engine in to let someone else take it now.

After a few phone calls they said I should check the pressure relief valve. After that it would be oil pump, pickup tube etc. From previous experience on other types of engines I said something like "well, you must have replaced all that stuff when you built the motor, right?". No. So I said "I see. Well, at least you disassembled it all, cleaned it, checked it and replaced it, right?" No. Apparently they unbolt the filter housing plate, dump it in the cleaner bath, paint it, and bolt it back on. I hadn't asked about this because I just assumed that no one would rebuild such an expensive engine and not replace the $13 pressure relief valve. I was dumbfounded. Makes me wonder what other craziness is in my engine.

Even though they said not to do priming I decided to try that first. No luck.

I did a little digging and looked at parts diagrams and learned about the oil to water heat exchanger (oil cooler) under the oil filter plate. It looks like it has two parts that could be called oil pressure relief valves. One requires removing the whole plate and draining coolant and all that. The other is accessible from the top of the filter mount towards the front of the truck. So I started with that one. Bolt and spring came off but I could not get the plunger to come out. After a bit of playing around I decided it was as far out as it wants to come. I pushed down a bit and it broke loose and went down a good half inch.

So, I am not certain if this is it, but it seems like any plunger with a spring should move kind of freely with the spring removed. I also found dirty old oil on the spring side of it confirming that this bolt was never removed when it was "cleaned" and whatever position it was in did not allow cleaner to get in there.

I figure that now that I know they did nothing to either of the moving parts on this plate except dumping it in a solvent bath which might have eaten up the plastic or Teflon or whatever parts of the other valve, I think I must pull this plate off, inspect it and replace most of it while I am at it. It isn't too hard to get to other than removing all my fresh new fluids and probably buying new gaskets that I already paid them for.

But what is going to keep me up at night is this: What if the problem that caused me to need a new engine in the first place is still in the engine I just spent thousands of dollars to rebuild? When it went, I was towing about 16,000 pounds up a hill with my foot in it. Out of nowhere I hear a loud knocking and shut it down as fast as I could. I now know the knocking was the #6 rod bearing. Suppose that while I was screaming along at full throttle and high RPM something went wrong with one of these valves and I lost oil pressure? At the time I only had the stock "gauge" so it wouldn't tell me for 30 seconds. I'll bet under those conditions, no oil pressure would hurt someone's feeling quicker than that. So I then pay some goof a bunch of money to fix the damage and they give it back to me with the valve stuck in the same spot?

Anyway on to the question. For the relief valve that I was able to pull with just the one 19mm bolt:

1. Why does it appear that everyone sells the other one that goes inside the plate but no one has this one?
2. Does it sound like it was stuck from what I said above?
3. Is there a circlip or something preventing this piston from being pulled out through the bolt hole?
4. Anything else you want to help me understand about this?

Thanks

 

[mwilson]

Please provide your engine serial number..

I’m pretty sure that both of the plungers are available through Cummins..

Shame on them for not disassembling the oil cooler and it’s internal items before cleaning...

 

[jghflys]

That is a good piece of detective work you have done. I do not think you will be able to clean the relief and check for binding with it in the truck. If you have to remove it, I would replace the 13 year old cooler assembly if you can afford it. They are expensive but you have done careful work so far and replacement should give good piece of mind.

 

[ofelas]

The relief spring is supposed to be 2.6 inches long and 1.62 inches compressed.

Take the plunger out and clean it, as well as the bore.

Put everything back, ideally with a new seal.

By the way - Summit sells a $19 pressure gauge that has a built in 1/8" NPT fitting that screws directly into the oil filter housing port. I bought one a few years back to diagnose, and never took it off.

Hope you get all this sorted out.

 

[mwilson]

Two valves in there as you have discovered, one is relief and the other is to regulate.

Where you have one that wont come out (they should slide right out) the entire mess belongs in the steel dumpster. I would not trust it.

We work on a lot of "B" series in various truck applications and can tell you from experience an oil starvation issue of any kind will take out Number 6 rod bearing first. Seen it several times. Then #6 and #7 main bearings will follow if the engine is not shut down quickly...

A broken piston cooler nozzle will cause low oil pressure issues too, but you need to resolve the stuck plunger thing before you go any further...

 

[TFucili]

Update: I spoke to the builder. They are on about strike 6 with me. They said they never do the priming and never need to as oil pressure always comes right up. Keep in mind that this is an automotive machine shop. They do machining and also assemble long blocks. They do not install engines. They said they have never heard of this problem. They were at a loss as the owner is on vacation this week. They were stumped because I am doing the install myself. I think they wanted me to bring it to some shop to have them sort it out. I spent way too much time getting the details right when I put the engine in to let someone else take it now.

After a few phone calls they said I should check the pressure relief valve. After that it would be oil pump, pickup tube etc. From previous experience on other types of engines I said something like "well, you must have replaced all that stuff when you built the motor, right?". No. So I said "I see. Well, at least you disassembled it all, cleaned it, checked it and replaced it, right?" No. Apparently they unbolt the filter housing plate, dump it in the cleaner bath, paint it, and bolt it back on. I hadn't asked about this because I just assumed that no one would rebuild such an expensive engine and not replace the $13 pressure relief valve. I was dumbfounded. Makes me wonder what other craziness is in my engine.

Even though they said not to do priming I decided to try that first. No luck.

I did a little digging and looked at parts diagrams and learned about the oil to water heat exchanger (oil cooler) under the oil filter plate. It looks like it has two parts that could be called oil pressure relief valves. One requires removing the whole plate and draining coolant and all that. The other is accessible from the top of the filter mount towards the front of the truck. So I started with that one. Bolt and spring came off but I could not get the plunger to come out. After a bit of playing around I decided it was as far out as it wants to come. I pushed down a bit and it broke loose and went down a good half inch.

So, I am not certain if this is it, but it seems like any plunger with a spring should move kind of freely with the spring removed. I also found dirty old oil on the spring side of it confirming that this bolt was never removed when it was "cleaned" and whatever position it was in did not allow cleaner to get in there.

I figure that now that I know they did nothing to either of the moving parts on this plate except dumping it in a solvent bath which might have eaten up the plastic or Teflon or whatever parts of the other valve, I think I must pull this plate off, inspect it and replace most of it while I am at it. It isn't too hard to get to other than removing all my fresh new fluids and probably buying new gaskets that I already paid them for.

But what is going to keep me up at night is this: What if the problem that caused me to need a new engine in the first place is still in the engine I just spent thousands of dollars to rebuild? When it went, I was towing about 16,000 pounds up a hill with my foot in it. Out of nowhere I hear a loud knocking and shut it down as fast as I could. I now know the knocking was the #6 rod bearing. Suppose that while I was screaming along at full throttle and high RPM something went wrong with one of these valves and I lost oil pressure? At the time I only had the stock "gauge" so it wouldn't tell me for 30 seconds. I'll bet under those conditions, no oil pressure would hurt someone's feeling quicker than that. So I then pay some goof a bunch of money to fix the damage and they give it back to me with the valve stuck in the same spot?

Anyway on to the question. For the relief valve that I was able to pull with just the one 19mm bolt:

1. Why does it appear that everyone sells the other one that goes inside the plate but no one has this one?
2. Does it sound like it was stuck from what I said above?
3. Is there a circlip or something preventing this piston from being pulled out through the bolt hole?
4. Anything else you want to help me understand about this?

Thanks

Now knowing of the original failure, it most definitely points to a previously existing issue.