oil light on for one second at start

[Touchdown038]

Lately, when I've been starting my car when it's cold, the oil light has stayed on for around a second and then turns off and doesn't come back on. The timing chain is also flapping around like hell, even though I just changed it last year.

I'm thinking that the oil pump is going out. Can anybody else confirm this?

[Nismo_Freak]

Don't jump to conclusions... oil is gonna be really cold when you first start the car in this weather. So proper warm up is more of a priority now, just FYI.

Check your oil level and condition.

[Touchdown038]

Oil's exactly halfway in between full and empty, and it's fresh, only about a month old.

[NISTECH]

what kinda filter you running? I would say get a factory oil filter on there and see if this helps keep the oil top side for start up. But as nismo said when it gets cold out that oil be thick on start up. take a bit for the pump to get it circulating good.

[Q45tech]

"it's fresh, only about a month old." Month old oil is not fresh as 1/3 of it as new spec life is gone [unless you haven't run the car for 20 hours in the last month].

Anyway the hot idle oil pressure is worse with BRAND NEW OIL AND FILTER.

Most oil senders work around the 3psi range to just prove some oil is circulating............always good to measure the hot idle pressure with an accurate gauge at least once per year to make sure it is above 14 psi worst case [at idle].

[Nissan24z]

I've had my 1995 240sx-se for 5 yrs. and the oil light has come on for a second everyday since I've had it.

[Touchdown038]

Sorry to bring this thread back, but my problem is getting worse and I figure now is the time to fix it before it's too late.

I just changed my oil with Castrol Syntec (which I've had it on since I bought the car a year and a half ago) and a new Fram filter, and the oil light still stays on for a second at start, and as far as I know it hasn't always done this. The timing chain still flaps around whenever I start it when it's cold. Does anybody else have this problem?

The reason I ask is because my engine has been making louder and louder tapping noises when the engine is cold, although it almost disappears when it is warm. And although I haven't tested the oil pressure with a gauge, I would be willing to bet that it is not up where it should be.

[Q45tech]

Unlikely a 15 year old engine is anywhere like new even with Mobil 1 changed every 90 days.

Without you supplying a graph of the oil pressure vs time and coolant [oil temp would be better] temp...........little can be accomplished but guessing. Also the ambient temperature and oil viscosity.

We can say for sure the engine is worn.

[Mikea240sx]

This is a bit unrelated, but Fram filters are VERY bad news. The endcap on the filter (inside) is made of cardboard instead of meta (like in most filters). It will eventually fall apart, and it'll be like running mulch through your engine.

[IvoryJ30t]

also, before you jump to conclusions, replace your oil pressure switch. its probably worn/plugged. if the light stil comes on, you have issues.

[Nismo_Freak]

Sorry to bring this thread back, but my problem is getting worse and I figure now is the time to fix it before it's too late.

I just changed my oil with Castrol Syntec (which I've had it on since I bought the car a year and a half ago) and a new Fram filter, and the oil light still stays on for a second at start, and as far as I know it hasn't always done this. The timing chain still flaps around whenever I start it when it's cold. Does anybody else have this problem?

The reason I ask is because my engine has been making louder and louder tapping noises when the engine is cold, although it almost disappears when it is warm. And although I haven't tested the oil pressure with a gauge, I would be willing to bet that it is not up where it should be.

The sending unit could be going out, I've had to replace sending units on about every Mazda truck in central Texas it seems lol.

[NISTECH]

the noise indicates a lack of oil pressure. do the graph as dennis said.

[Touchdown038]

Ok, I went out and bought an Autometer mechanical gauge, but I can't find a place to T the oil line from. Is there anybody on here that has installed a mechanical oil gauge?

[Nathan]

If the threads were the same I'd just replace the stock sending unit with the mechanical gauge. I'll check it tonight when I get home as I need to do the same thing actually but I ALSO have to work a turbo oil feed into the system

[Touchdown038]

Yup that's where I figured I'd do it, and I heard it was right by the oil filter, but I'm having some trouble finding it. Is the location the same on the SOHC motor as on the DOHC motor?

[Nathan]

Shoot, I didn't notice it was a SOHC I would assume it would be similar though. If you look on the "sandwich" that goes between the block and the oil filter you should see a brass coloredish nut with a wire coming out of it going to the harness, that should be the sending unit. It's right next to the filter, on the front side for a DOHC. Like I said, I'll check it out when I get home in a bit and at least tell you if my summit oil pressure gauge will screw into it. I MIGHT even be able to tell you what thread size/pitch it has if I recognize it.

[Touchdown038]

I might sound like a n00b asking this, but doesn't the sending unit send an electrical signal to the ECU? And if so, isn't it useless for a mechanical gauge?

[DAEDALUS]

The sending unit is an open/close switch that lights the oil light if the pressure falls below a certain value. You remove the sender entirely, and measure the pressure directly with the gauge.Do a search...there's been some debate about the threads. Apparently a lot of Nissans don't have standard British pipe thread (most oil gauges use BPT), but they're *very* close, which makes it kinda easy to try and force the wrong fitting into the aluminum.

[Nathan]

which makes it kinda easy to try and force the wrong fitting into the aluminum.

You say that like it's a bad thing...as long as it fits and doesn't come out, all is good in my world

[Touchdown038]

Alright, found the oil sender, but it's getting dark so I'll try and remove it tomorrow and see if the threads are the right size.

Thanks for all the help so far guys.

[Touchdown038]

OK, today I removed the oil filter in hopes of getting a wrench up on the sender, but I didn't have a big enough size to take off the sender. What size is the outer part?

EDIT: I also discovered from looking under the car that my oil pump is now being held in by only two bolts instead of all four. Must have screwed up doing my timing chain install, now I'm kicking myself for it. Could that be the cause of low oil pressure?

[NISTECH]

oooooh yea it could your probably sucking air in by the gasket. get a gesket set for it replace both gaskets and reinstall all 4 bolts run it for a bit then recheck it in the morning.

[Touchdown038]

Cool.... I bet it's gonna take awhile for the gaskets (pump body and to block) and the other two bolts to come in from the dealer (they must have fallen out while driving) so I'll be sure to keep you guys posted.

[PalmerWMD]

This is a bit unrelated, but Fram filters are VERY bad news. The endcap on the filter (inside) is made of cardboard instead of meta (like in most filters). It will eventually fall apart, and it'll be like running mulch through your engine.

I adamantly agree.Fram filters---> do not use.

Fred...

[NISTECH]

yea what they said. I put it a bit more bluntly though. Any Fram product sucks. Their longevity is aweful. Strickly my personal opinion of course.

[Touchdown038]

Sticky in mind: Replace with Genuine Nissan oil filter.

I also have a question that needs to be answered.

Is the timing chain tensioner really actuated by oil pressure? Because as I was driving (to the dealer and back, not driving at all until the parts come in) I kept hearing what sounded like the timing chain rattle every time I pushed in the clutch and let the RPMs drop (usually from 2000-3000 rpm.) And I do hear it for a couple of seconds whenever I start the car.

I did the timing chain job at the end of last year, however, and so I figured the noise is probably due to low oil pressure since everything else under the cover is new.

[Nathan]

Yes, the timing chain tensioner IS actuated pretty much 100% by oil pressure, theres a spring in them but it's not doing a whole lot of the work at all.