Low (No?) Oil Pressure

First, thank you for all the responses.

As mentioned in the original post, oil level was perfect and by the vehicle's oil change reminder, it claims 15% time remains. I don't remember the mileage at the time of the last change. I will need to find that receipt.

A very good point on the powertrain warranty. That is something that I will investigate tomorrow. By the documentation, it should be covered since it is under 5 years /100k miles. And if covered, what a relief that will be!

My father used to own a shop, and has looked it over also. There wasn't any debris or one of those filter tabs in the oil filter housing area. That was one of his first concerns. He has never taken one of these apart, and why he suggested posting here. Most of his work was racing, street rod, and NHRA Pro Stock engines. He was also concerned (and told me off a bit) that the last oil change was at JL instead of doing it myself---was in a hurry.

**UPDATE**

The oil pump "exploded" --- and hopefully all of the pieces, shavings, shrapnel and flakes ended up in the pan and nowhere else.

The dealership is claiming that just replacing broken components and testing for proper pressure and ensuring VCT screens are clear should be enough. Parts arrive Monday, and then they begin testing. My dad went off on them a bit today, that if the pump blew up and also killed the cover/housing, that they cannot be 100% certain the engine is free of metal that could create a problem in the near future. They claimed the transfer passage was clear (pump to filter), so we should be OK with their conclusion, and all should be perfect after this repair. He wanted them to replace the whole engine, but they cannot make that decision until doing all this other stuff first, due to GM's procedural obstacle course. The dealership then made the comment that I still have powertrain coverage "until November or up to 100,000 miles". Not a lot of comfort in that with only 45k on it now and that I don't put many miles on it anyway.

But now we all know that these oil pumps can actually hand grenade with no apparent explanation.
:blowup:

Hi Guys:

I'm Bsolace's father. I decided to register here in the forum and post on this as well, since I've been following the thread and obviously involved in what is going on. I greatly appreciate your responses, and especially in directing him to the powertrain warranty. I just took it for granted that it had probably expired.

When I spoke to the dealership yesterday, I too was concerned about a variety of secondary issues that could come from this. From my experience, when something like this occurs, it is rarely instantaneous. There is often a lead-up, or a combination of events that build into the more serious damage. For example (Noting that I have never personally taken one of these engines apart), did a bushing start to fail, creating excess clearance; or, did the pressure spring fail or bind, causing harmonics in the pump components and violent pump vibrations led to the failure. They had NO answers to any of these questions, and had no idea how this failure occurred.

If I had more knowledge or experience with this particular engine I could probably develop a theory or two to the actual cause. And believe me when I say that it frustrates me that I have not received a conclusive causal response from the dealer. I almost went over there today to inspect the components and take pictures myself.

I too am concerned about running time without oil pressure, but not so much "after" this event occurred. In that respect, I know my son shut the engine down almost immediately---as soon as he could make a safe stop. And between that and testing before we hauled it off to the dealer it only had a few seconds of operation. I'm more concerned with what happened prior. Even though the dealership claims the transfer passage is clear, and the only metal is large pieces in the pan, my experience forces me to question that statement. As most of us probably know, it only takes a very small piece of debris (metal, babbitt, rubber, plastic, or virtually anything) to stick to a bearing, or wait hidden somewhere to clog an oil passage. If either occur, it is only a matter of time before the engine is just a bucket of broken parts. I'd like to be assured that the bearings and other critical components are still pristine in this engine.

An example I can provide here regarding after-effects is that a family member was once involved in a traffic accident where their vehicle was hit quite hard by someone who ran a red light, launching their vehicle across an intersection. The vehicle was repaired (body and chassis work), but a few months later the engine seized at freeway speed. When I pulled the engine apart I found that a very small piece of engine block casting had wedged itself in an oil passage. The vehicle was a few years old, beyond any warranty, and had 40 or 50k miles on it without ever having an issue. I was able to use various tools at my disposal to find where the casting came from, and found that this piece was able to avoid ever reaching the filter. It was just the right shape that it took an exact position to block the passage. With my analysis and reputation, this person was able to bring the insurance company back into the picture and add a new engine to the accident claim. They were lucky in this example.

The dealership working on my son's Cruze told me that they will be testing pressure and flow somehow. (I'd really like to see how they plan on doing this, considering the design of the pump, pickup, filter, etc). I suspect they could have a tool or device that attaches to the suction passage while also spinning the engine as a way to prime the system. However, I do not see how that is possible without adding wear to critical components, using the engine as its own spintron. On engines that I've built, I always have a way to prime the lubrication system, measure pressure, etc., without spinning the engine, yet turn the engine by hand during this process to move oil through all passages. I do not see how this is possible in this particular engine---but I could be wrong.

When I asked why they were not just replacing the engine, I receive multiple explanations (or excuses). 1) This is the procedure required by GM; 2) They need to replace these components and test first. Then, if "something" is not right they proceed to the next level of replacement (whatever that is); and 3) They don't see metal anywhere else or floating/suspended in the oil. The first sarcastic thought I had with this, is that my son should have just drove the car home, and if it launched a connecting rod along the way, so be it ---it would clearly need a new engine. However, he is much more responsible than that! How then, would the dealer be able to prove oil system (exploding pump) was the cause and not a dysfunctional driver? Sounds like an easy way to blame operator error if different decisions were made. Makes for an interesting discussion...

Again, thanks for your feedback. If we can get pictures or other information on this failure I will make sure that one of us post the details. Have a great weekend!

Regards,

Thanks carbon02:

I really appreciate that link, especially that one of the posts included a video showing the oil pump operation. Although his images don't show many of the explicit details, it does give me pause in accepting the dealership claim that metal is only in the oil pan, and could not have gone anywhere else. By their own description, pieces were in the suction passage and the pan itself---but not in the transfer passage to the filter?!? The transfer passage seems to have the larger initial opening size, and is in the direction (flow) of what would have been pressurized with oil before the pump's failure. One would expect to find metal in this passage.

One thing I noticed in the video, is that even when that pump is turned by hand (even though it is dry) it seems loud. This suggests a considerable fluid balancing requirement, where if suction was lost---for example, if the gasket between the pan and housing did not seal perfectly---the pump could disintegrate rapidly if oil flow to the pump was lost. While the design is efficient and looks very light, durability and tolerance for minor errors (low oil, lost sealing at suction passage, or something else) may not bode well for this pump.

In my experience, I've only seen three oil pump failures (in common V8 engines). None of which were from engines I built. One was due to modifications to the pump that made clearances too tight. The unit heated up from friction and seized, shearing the drive shaft and doing considerable damage to other internal engine components. Another was where clearances were too great, causing chatter that turned into harmonics and a pressure imbalance that bound the gears. The third was a dry sump system on a very expensive engine where the installer was (what is a politically correct term?) a pig that did not practice thorough cleaning of components. His assembled braided lines and fittings were not properly flushed, and some rubber plus a piece of steel wire braid wedged in a chamber and seized the pump. Yes, it takes quite an effort to seize a quality dry sump pump, but he succeed. A testament to how sloppy the guy was.

I'm hoping to inspect the components from my son's Cruze to see if I might be correct in my assumptions.

CenturyPerf,

I understand your concern and questions.....one wrench to another.

Problem is, dealer mechanics generally don't get involved with failure analysis.....the mission is to get the car (and customer) back on the road with an eye towards minimal customer inconvenience.

The dealer has to fill in three sections, known as the three 'C's.....customer Complaint.........Cause (of failure)......Correction (of the failure).
In this case, the three 'C's are: customer Complaint: Oil pressure/stop engine lamp on......Cause: catastrophic oil pump failure....cannot make pressure......and finally, Correction: replace pump assy as required.
There should be a section for 'OLH' or, Other Labor Hours.
This is a variable time charged to warranty to inspect for consequential damage and as I said earlier, I cannot imagine a repairman not performing these inspections prior to reassembly.

This is a rather simple oiling system with one exception......the oil pump output is variable.....I wouldn't be surprised if, for some reason, this one hung up in a full pressure mode, causing a hydrolock situation and fracturing anything in its way.
As you can see, though, the routing is: pickup to pump, pump to filter housing, filter housing to lube points.
Other than the main run, pump to filter housing, I don't, or can't identify, any debris catching points......it would be wise to pull the filter housing to be certain there is no obstruction in the run, but, if it gets through it'll get trapped in the filter anyways.

Since the failure was catastrophic, or instantanious, the pressure/volume loss was instant as well, so the odds of debris being ejected into the run are remote.

For now, let the dealer do their thing. They have to follow corporate guidlines since the corporation is footing the bill.
If something hidden pops up you have documentation of the incident.

Regards,
Rob