Low oil pressure...

[ajkulish]

Hey guys

Backstory: Last year I had a wastegate failure on my car and the symptoms of a blown head gasket. The coolant temp would rise very quickly, the motor did not want to build boost. The seals in the CHRA blew and the turbo must have cooked when the car was parked. (Drove to destination without issue, when I restarted the vehicle to leave a few hours later the turbo was grinding). Other than the jacked up turbo and cooling issues, the car ran totally fine under vacuum. Oil pressure was good, and so was vacuum.

Anyway, got the turbo (GTX 3076) set up with a new CHRA, and got everything to replace my headgasket. Having all of this time on my hands, I got back into the project. The headgasket didnt look too bad, but knowing that looks arent everything, I replaced the HG and put the motor back together. I was very meticulous about making sure all my T's were crossed and I's dotted.

Since I had to take the timing cover off, the car sat without oil for a few months. Thinking some contamination to the system was possible over this time, I filled the car with high mileage 5w30 for the first start, let it idle for 10 or 15 minutes, then drained it, change the filter, and replaced with Rotella T6. I have no leaks, everything runs good, sounds good, feels good, drives good, etc. But for whatever reason, I am getting oil pressure as low as 10 psi after 10 miles of driving. On a cold start, I am only seeing a maximum of 56 psi.

What I've tried: I swapped the prosport electronic sender out and replaced with a cheap mechanical oil pressure gauge. Yep, same pressure on both gauges. I even tried to stall the car when the oil pressure was low and saw as low as 8psi, but the factory oil pressure light did not flicker. I understand that it could be mains or the oil pump, but both of those only have 10k each on them. During the repair, the only things that were changed on the car were the oil drain line on the turbo (not leaking or pinched), full EGR delete, and the radiator.

I want to get this remedied, but before I get into replacing pumps and bearings, I want to make damn sure that I have checked anything else that it could be. I am going to drain the fresh oil again and see if there are any flakes in it, and maybe take off the pan and see if I can find any clogs in the oil pickup line. But, I just really do not want to swap out bearings and a pump just to fire it up and see that I still have a pressure issue.

Any suggestions are very appreciated. Thanks!

 

[gotovato]

As per the owners manual/service guide


what oil pressure are you seeing with the engine warmed up if you hold it at 3000rpm? I agree your pressure seems to be on the low side, but for this engine, that picture above is what’s called for.

 

[ajkulish]

As per the owners manual/service guide
View attachment 14119

what oil pressure are you seeing with the engine warmed up if you hold it at 3000rpm? I agree your pressure seems to be on the low side, but for this engine, that picture above is what’s called for.

Thanks for the reply. I see about 35 psi at 3k rpm cruising, maybe a little more. I can verify this number tomorrow. Close to the low end of things, but I'd rather be on the high end. I forgot to mention, that this is a built motor big turbo car. Only 10k on setup and this is the first of the issue. Before replacing the HG and radiator, the idle oil pressure was regularly between 18 and 21 psi.

 

[gotovato]

If it’s a built motor there’s a high chance your clearances are looser then stock. Actually pretty much for sure. I’d be running at least a 40 weight oil. That’ll help some. Also with that test in the manual, do it while parked and see.

 

[ajkulish]

Right, I understand that may be the case. If it is indeed bearings, then it is just very strange that the clearances increased via the car sitting still, and the engine not turning. Like I said, the last time the car ran before yesterday the oil pressure was just fine.

 

[gotovato]

Right, I understand that may be the case. If it is indeed bearings, then it is just very strange that the clearances increased via the car sitting still, and the engine not turning. Like I said, the last time the car ran before yesterday the oil pressure was just fine.

fair enough. This makes sense. I’d say try the 3k rpm hold test. 43psi and up you’re good. Below that, the next thing I’d try is a 40 weight oil. But it’s possible you may have gotten something in the motor which the bearings didn’t like

 

[JohnnyTightlips]

I would switch to 5w40 and send it. I would then watch my oil level to see if it is being lost anywhere. If pressure is good with the 40w and oil is not being lost at some crazy rate and the pressure remains constant than keep sending it.

 

[aaronc7]

I had some junk in my old Miata oil pickup screen that probably was causal for low oil pressure and eventual spun rod bearing 1k miles later.

Something ain’t quite right and made it change. Sucks but I would go back over everything.

 

[ajkulish]

Really hoping it is something in the screen, I will find out later today if the rain holds off. I spun a bearing in the past due to being a rookie but that was very clear with the sound it made. Not sure if i would be experiencing any NVH differences from a potentially "failing" bearing.

And the oil is 5w-40 already, wish I could send it However, it does have me wondering if the relief valve in the oil pump is not seated properly or something. Before the repairs, the oil pressure was 82 max every time i started it up. Now, I havent seen anything over 56. i have seen 56 a few times, but never 57.

 

[ajkulish]

Alright guys, update. Went back through it today on a short schedule. Drained the 5w-40 Rotella T6 and took a close look at the oil. There were a few minuscule flakes in the bottom of the filter, but having seen what a spun bearing looks like, what I saw did not look very alarming. I pulled the oil pan off, and found that the bottom was a bit sludgy. I attribute this to leaving the drain plug in while it sat and it is probably just the result of dirty oil runoff that dripped down over the months. However, I did end up finding some tiny flakes of plastic in the oil pan. No metal flakes, but about a dozen tiny pieces of plastic. I am not sure what it is. I took the oil pickup off and took a look inside - it looked a little dirty but I could breathe through it easily, cleaned it out and still the same. I shook the pickup tube, finding a few more tiny slivers of plastic but it did not look like the mesh material of the screen. Took a look through the rest of the bottom end and everything looks clean for 10k miles and nothing looks out of place. Inside of the oil pump pickup looked clean. Not sure what to think yet. Planning on plastigaging the mains to see if they are off, but I still feel like I could be overlooking something. Also something worth noting - I took a pic of the oil filters I have used recently. One had a couple thousand miles on it, one was just used for the 15 minute driveway idle upon first start up, and the other was used when I took the car out for a 10 mile drive. The two that I have used since the repairs look crushed, and I don't really know why, or if it has any consequence. But regardless, pictures below. Going to think on it for the night.

 

[JohnnyTightlips]

Alright guys, update. Went back through it today on a short schedule. Drained the 5w-40 Rotella T6 and took a close look at the oil. There were a few minuscule flakes in the bottom of the filter, but having seen what a spun bearing looks like, what I saw did not look very alarming. I pulled the oil pan off, and found that the bottom was a bit sludgy. I attribute this to leaving the drain plug in while it sat and it is probably just the result of dirty oil runoff that dripped down over the months. However, I did end up finding some tiny flakes of plastic in the oil pan. No metal flakes, but about a dozen tiny pieces of plastic. I am not sure what it is. I took the oil pickup off and took a look inside - it looked a little dirty but I could breathe through it easily, cleaned it out and still the same. I shook the pickup tube, finding a few more tiny slivers of plastic but it did not look like the mesh material of the screen. Took a look through the rest of the bottom end and everything looks clean for 10k miles and nothing looks out of place. Inside of the oil pump pickup looked clean. Not sure what to think yet. Planning on plastigaging the mains to see if they are off, but I still feel like I could be overlooking something. Also something worth noting - I took a pic of the oil filters I have used recently. One had a couple thousand miles on it, one was just used for the 15 minute driveway idle upon first start up, and the other was used when I took the car out for a 10 mile drive. The two that I have used since the repairs look crushed, and I don't really know why, or if it has any consequence. But regardless, pictures below. Going to think on it for the night.

Maybe new o-ring on the oil pickup? Also check the BSD plug if it's leaking you will lose pressure there too.

 

[ajkulish]

Good looks, I will take a close look at both of those o-rings

 

[Easter Bunny]

I have a pu so no cartridge filter for me on ms3 but I have had them on other cars and usually had a link in them like you have. I think it is because the filter is a little taller than it needs to be so when you tighten down it binds a touch and turns with the cap

 

[ajkulish]

I have a pu so no cartridge filter for me on ms3 but I have had them on other cars and usually had a link in them like you have. I think it is because the filter is a little taller than it needs to be so when you tighten down it binds a touch and turns with the cap

I kind of figured as much, guess I didnt have it tight enough before haha. May switch to a canister filter while I am down here anyway. That cartridge is such a pain.

 

[Solarsurge]

Those “plastic” chunks in your oil pan appear to be the same color as the silicone sealant that’s crumbly all around the edge of the pan. Looks to me like it’s just bits of sealant that broke off and fell in the pan. The only thing plastic inside the engine are the chain tensioner rails and if they’re broken, you’d have much more noticeable problems than low oil pressure.

Edit: After second thought, it’s definitely worth a peek at the oil pump chain tensioner just to make sure that’s still intact and not damaged. Could be a minor blessing in disguise if you catch it before it totally fails.

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[JohnnyTightlips]

Those “plastic” chunks in your oil pan appear to be the same color as the silicone sealant that’s crumbly all around the edge of the pan. Looks to me like it’s just bits of sealant that broke off and fell in the pan. The only thing plastic inside the engine are the chain tensioner rails and if they’re broken, you’d have much more noticeable problems than low oil pressure.

Edit: After second thought, it’s definitely worth a peek at the oil pump chain tensioner just to make sure that’s still intact and not damaged. Could be a minor blessing in disguise if you catch it before it totally fails.

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The pump pickup tube is also plastic. Not sure how it could get eaten though.

 

[Solarsurge]

The pump pickup tube is also plastic. Not sure how it could get eaten though.

It’s black though. The only thing that’s cream colored plastic is the oil pump chain tensioner. The other parts are brown and black.


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[JohnnyTightlips]

It’s black though. The only thing that’s cream colored plastic is the oil pump chain tensioner. The other parts are brown and black.


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For sure, I have pics of all that in my build thread.

 

[Solarsurge]

Just in case the OP is not familiar, this is the part you want to double check. Should be smooth all the way around like this. IF those bits are actually plastic this is the only possible source of that color plastic.


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[ajkulish]

I believe my piece like that is actually orange. But I had just gone through all of the timing and had to look at those parts closely. I do not remember seeing any damage to those parts. Frankly, the bit of plastic does not look like anything I am familiar with in the engine. Wondering if it is maybe something from the PCV system?

I will likely end up taking the timing cover off and take a peek at this again. Also planning on plastigaging the mains to see where I am at from a clearance standpoint.