2006 MCS R53. 70,500miles


I have a specific oil pressure problem that I haven'tseen anywhere else on these forums. Specifically, when I start from a stop, my oil pressure drops to zero for a second or two then recovers if I let off the gas a little. The idiot light comes on at the same time. At that time my idle oil pressure was low butnot zero.

I change my oil once or twice a year. Before this problem, I had changed my oil inspring when I changed my winter tires for summer tires - maybe late April. 5w30 Valvoline full synthetic. The problem first happened about three weeks ago after a 90 mile trip in clear weather at about 90 degrees - the oil was low but only 1/4 quart or so. When I got on the gas - not hard, but maybe a little harder than other randos on the road -the oil pressure would raise with the RPMs then drop to zero. It would jump back up to where it should be if I let of the gas a little or the RPMs got high enough (around 2k-2.5k I think, but I don't remember exactly). It would also do this in second, but third and higher and the gauge acted normal if a little low. I didn't notice any noise and the engine acted exactly as it always has during the drop-out.


So, I hopped on the forums and my car hypochondria kicked in - I thought for sure the death rattle was striking. The engine isn't exactly quiet, but at this point I'm pretty sure it's not the death rattle. I did try to get to the timing chain tensioner, but the stupid wheel well lining screws kicked my butt... Not much makes you feel like less of a man than being bested by a bit of plastic...


Maintenance I have performed since the issue started:

--I changed the oil (I always use Wix filters and they have the plastic cage in them)- the oil was dark with just a hint of gold when backlit. Probably still good considering I rarely use the car for anything other than groceries or work 2 miles from my house. After the oil change, my idle oil pressure was back up to what I'd consider normal. I didn't think to check the bypass valve on the oil filter housing before buttoning it back up.

--I changed the oil pressure sensor. (I also did some coolant system work, but that shouldn't apply to this problem).

I've found posts about low oil pressure at idle and a couple with low oil pressure when cornering hard, but none when accelerating. It should be noted that while I'm mechanically apt, I'm little more than layman with vehicles (most of my mechanical experience has been on aircraft). I'm also a bit gun-shy about making the problem worse. It should also be noted that my closest Mini/BMW qualified mechanic is 4 hours away.


I've spoken to some folks I work with who have more small engine experience than I do. A tentative conclusion I've come to is it's probably not the oil pump. When oil pumps go out, they don't drop pressure then come back up (or so I've been told). It's not the oil pressure sensor because I just replaced it. It's probably not debris (like the plastic timing chain guide) because a clogged port probably wouldn't drop in and out at those specific times. It might be a chafed wire that grounds out with acceleration torque. I haven't chased the wire yet - I intend to when I get home - providing I can do so in that tiny freaking engine compartment (I still have bruises on my forearms from jamming my arms into little spaces).


I'd like to throw a mechanical oil pressure gauge on it to see for sure what the pressure is since the cabin gauge is computer derived. I'm not sure if this is feasible considering it only happens while under load. My other option after chasing the wire is installing an oil pressure gauge. This is a bit more than I feel comfortable with. I can't really afford to have a shop do it, so I'm researching guides on the forums. The mechanical gauge seems like my best option as I don't want to have to wire in an electrical gauge. Sounds like ~ $150 or so for parts, which is doable.


Any thoughts would be appreciated.

 

These are your best bet. All else seem very improbable.

I am perplex without a pressure gauge, how do you know if the oil pressure is too low, or back to normal. Do you have a chrono pack?

 

Yes, my center console has oil temp and pressure, coolant temp, and fuel quantity. I understand the oil pressure gauge is computer derived, however, and isn't necessarily accurate.


*EDIT* Do you think the filter bypass could cause low oil pressure while accelerating and no other time?

 

Please take a good photo of your "bad" oil pressure sensor, as well as the part number on the sensor. There is rumor that the oil pressure sensor for the Chrono pack option is identical to one without. Which means it is only capable of detecting when the pressure drops below circa 3 PSI and the sensor is a on/off switch type.

If this is true, the reported pressure on the "gauge" is manufactured fake news, so any tall tale is possible.

 

I checked MINI's oil pressure sensor. There is only one and is same for Chrono pack or not. It is just a go/no-go switch. That points to manufactured fake news. Also this post in this thread.

If it were me I will carefully unscrew the oil filter cap and examine the bypass valve. The key is not to disturb and erase the evidence. You don't need to drain the oil nor replace the filter to do this.

Also you should read the above thread.

 

the oil pressure gauge on your r53 is a best guess on the part of the computer same with the oil temp. If you decide to put in a oil pressure gauge you will be best off buying one of these to make it happen https://www.waymotorworks.com/tapless-adapter.html the adaptor will help you prevent leaking and will allow you to keep the factory oil sender.

Now to the meat and potatoes of the oil pressure issue I had the similar issue with mine and it turned out to be an o-ring on in the timing cover / oil pump.
​​​​​​https://www.northamericanmotoring.co...s-at-idle.html
my issue was once the car was warm and at idle but I could see something like what you are having happening if one of the o-ring was bypassing AKA leaking.

 

I came home after work (took my motorcycle) and found out that I had forgotten to reconnect the wiring harness to the oil pressure sensor/sender. Initially I was happy, hoping that was the end to my problem. No such luck. Strangely, the gauge was acting the same with the old sensor as it did with the wiring harness disconnected from the new sensor.
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So, I reconnected the harness and drove it around the block a few times to get the temp up. After the temp came up, for about a block the gauge went up and down, then it stayed down. This is the first time it has read zero at idle. Sound and performance appeared good - no obvious noises or performance degradation.
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Now I'm waiting for the engine to cool down and I'll take the oil filter out and take a look at the bypass valve and see if anything is broken. If the housing looks good, I might have to follow Jason's link and take off the timing cover and see what I can see. I'm beginning to get over my head.

 

If you haven't mess with the timing chain cover like he did, I don't see why you will want to do that. Get yourself a real pressure gauge before you start to shotgun troubleshooting.

 

I agree totally! my thread is a good read for ideas as to where to go. the timing cover should be the last thing on the list of things to remove.

 

you never mention what oil weight you use...

Oil pressure is dependent on few things:
*internal clearances /rings/bearing etc
*oil weight/blend
*temp

Hot oil flows well.. it has LOW pressure

If youre running a 20 or 30w oil when its 100f and seeing this.. try a thicker at temp 40w.. like a 10w 40 (as its unlikely you will find a 10/20 or 10/30)

 

Maybe the drain back plunger under your filter. that little ***** is a PITA. Ask me how I know.

 

"you never mention what oil weight you use..."

I did, actually, but it was a long post, so I don't blame you for passing over it. Usually I use 5w30, but I traded up for 10w30 when I changed the oil.

 

Looks good to me...

the black plunger seemed loose, but I don't know what it normally feels like...

Holy crap with the huge pic...

 

This is a long shot, but try checking your oil filter canister....You should have this updated one:


And not anything similar to the old one here:

If you lose the loose parts like the spring or the cage, you'll lose pressure.

Or, you could've bought the early uncaged oil filter version which collapses...When it does, so goes your oil pressure...


You should grab the updated caged filter to keep it from collapsing...

*pics above are from minimania

 

I definitely have the new one. I always stick the filter's large hole on the circular ridge on the cover and there's always positive pressure so the filter doesn't just fall out when I turn the cover over. My filters have always had the integral plastic cage.

Thank you for the suggestion.

 

Your photo of the bypass valve seems OK. First of all, you need to stop reading the pressure gauge on the Chrono pack. I don't care what wonderbar algorithm one cannot create something from nothing. The stupid code uses coolant temperature plus the go/no-go oil pressure switch to manufacture the so-called oil pressure. It is garbage in, garbage out, referred to in computer science.

Why aren't you use MINI filter? Does your filter have this plastic ring to properly engage and depress the bypass valve?



You should have taken a photo of the oil filter when you check the bypass valve.

The other big clue is did this low pressure symptom happen right after you change oil and filter?

There are photos on the web of **** filter collapse.

this is a BMW but similar




You really need to get a real oil pressure gauge pronto. I have seen too many owner ignore the gravity of low oil pressure and ruin the engine. The most unfortunate is the subsequent owner who has no idea. It take only seconds to do permanent damage with oil starvation.

 

Just a thought. As the Chrono pack gauge evidently uses coolant temperature and the oil pressure switch to manufacturer a fake oil pressure reading, it stands to reason if the temperature transducer becomes intermittent failing, you can get spurious oil pressure reading as a result.

p.s. the algorithm uses oil pressure switch, coolant temp, and engine RPM to fake out an artificial oil pressure reading.

 

No, the symptoms didn't happen soon after I changed the oil. It happened about 3 months after I changed the oil. Below is a photo of the oil filter I pulled out when I changed the oil this last weekend. This was after the symptoms started.

 

As a side note, This is all new to me and my local parts places blew me off when I asked (apparently they don't stock metric) - do you folks have an oil pressure testing gauge that you prefer? I'd rather not spend the money and time plumbing in a cabin gauge just to find out if there is any pressure.

 

The old filter looks good, as it has the raised plastic ring for the bypass valve to ride on. The Mini's oil pressure switch is not metric. It is a Chrysler Mopar part. The thread is imperial. I have the part number somewhere that I can't keep track of.

It is possible your problem is just a byproduct of the stupid algorithm, and your oil pressure is just fine - let's hope. The only way for you to find out is to get some real readings.

 

I got it. The oil pressure switch thread is 3/8" male NPT. Ask why I know? The engine has a Chrysler legacy.

 

Thanks Pwn. I just called around and found a kit with miltiple metric and imperial adapters. Going to test it and get back with you.

 

So, oil pressure tester connected, I idled the car until it reached operating temp - 20 minutes or so with no pressure drop. I ran the car up and down the driveway to put load on the engine and nothing. Then I went around the block several times with no drop. Then I went out on the highway for a few miles - I turned off several times so I could replicate the conditions it usually dropped, with no drop. Then I drove around my block a couple more times with no drop.

No drop on the gauge or tester at any time. I'm at a loss...

*EDIT* Lowest pressure on the tester was 12 PSI.

 

The oil pressure should be somewhat proportional to the RPM. Also the higher the temperature, the lower the pressure, as the oil becomes less viscous.

I try to picture what you did. I assume you can drive around with the test gauge connected, but not able to see it. With a helper you can watch the pressure changes as the engine RPM changes. Doing it with the car stationary but warmed up is good enough.

If you are seeing lowest of 12 PSI you should be good. Like I said, your alarm may just be this bullsh1t artificial so-called oil pressure gauge in the Chrono Pack. It is worst than having just an idiot light. I know someone has also report at time abnormal low pressure with the Chrono Pack in a 53k miles S. He never told me what he meant by low.

I would install a real oil pressure gauge. It is the first gauge to add in terms of usefulness. Oil temp - not so useful.

 

I have the test gauge strung through the passenger window at the moment, so I can see it while driving. I'm hoping the previous low pressure was BS, but it's hard to confirm until I see the cabin gauge drop and the tester stay up. I'm going to drive it around more with the tester attached to confirm. I do plan to get a mechanical oil gauge for the dash - probably in the next week or so.

I'll update if there's anything to update.

Thanks for the help.