Alright, well, because there is no ideal place to start with this topic, I'll go ahead and spew out my information and go from there.

A few weeks ago I bought R50, 137k miles, and seemed very solid. I did however notice that the oil pressure light was on, but decided to roll the dice on it. I worked that into the final cost of the car.

-At the time of purchase, the oil light was shutting off at around 1k RPMs. Now, post oil and filter change, it stays on till 2100.

-I noticed a decent amount of blowback from the filler cap; are these engines supposed to have such positive force?

-I've only noticed it more recently, however it may have been sooner, but there is a slight tapping on startup. After a might of driving it appears to go away.

-Now for the really fun stuff. I purchased an oil pressure testing kit, and swapped the sensor for it. Wham-bam, 0 PSI up until 3000 RPM, then it moves evenly to 3 PSI at 4500. Definitely not what the light showed.

I am fairly certain that the oil filter was installed correctly, however I could be wrong. I guess what I am trying to ask is where should I start? Cleaning/replacing the pickup? Taking off the valve cover and checking cleanliness/blockage/pressure?(Was already planning on doing this tomorrow). I will also do a wet compression test. The dry one turned out 185's, with a tolerance of 3 PSI on each. Would it be worth pulling the oil pan and checking out the underside, giving it a good cleaning?

There's something pulling me away from the issue being the oil pump, but I have been wrong before. I have also looked at 10+ threads, most of them leading back to either oil filter or catastrophic disaster.


Any insight would be appreciated, I'll have more information tomorrow. Thanks!

-Tanner



Update: Like many others, it appears that I have fallen under the curse of the missing bypass valve spring. I pulled the cap and sure enough, it was missing. Oh the words I would love to have with the dealer that maintained this . Would this cause complete loss of pressure of the engine?

I also took the valve cover off and am getting no oil through the top end, just what was there.

Lucky for me, I have a part available and can pick it up, but I am just wondering if there is another way I can check oil pump. I'd hate to fix this, only to figure out this was not the immediate issue. ANY advice would be appreciated, thanks!

 

Yes the pumps can go bad. If you have the bypass spring back in place, what is your oil pressure now?

The bigger question is whether you crank bearings are shot due to no oil pressure.

 

No bypass in place, still waiting for order. I thought I was getting no oil pressure, but I now notice that when I rev to above 4500 rpm, the oil pressure spikes up to 60 psi, then will stay stabile until around 1200, when it completely drops to zero. Then I have to rev high again to kick it back in. I also pulled the valve cover off to check the oil pump, and it follows the same routine. This to me points to that bypass valve, as it opens and closes hard.

If it was a clogged pickup or broken pump, it seems like the symptom would be more linear.

Crank bearings are questionable, would have been about 150 very light miles since this issue

-Tanner

 

Have you seen this thread with a home made fix?

https://www.northamericanmotoring.co...ief-valve.html

 

Yes, i have, but unfortunately the previous oil changer wasn't kind enough to leave the spring in there, so I don't have it. The c clip fix is also for the plunger, I believe. I will attach of clip of the rpm and oil pressure gauge working, too

Edit: here's the video, excuse the vertical crop:
https://youtu.be/BekNbLwWll4

-Tanner