Oil Pressure Woes

[1WheelWonder]

My Ka is completely stock internally, with over 170,000 miles on it. It has been turbo-ed now for about 8 months with absolutely zero serious issues, until recently. After installing my new diff last night my co-pilot(Little bro) and I took her for a spin. The car had been sitting for about 3 weeks prior to this night. It started up fine, oil pressure at idle was good @ about 50psi cold. After cruising for awhile I began to dawg the piss out of it, in which it felt really strong, no sputteres or odd noises. On the ride home I noticed my oil pressure at 3000rpms was at 25psi where as it's usually at 50psi under slight load and at idle it was at 10ish psi where normally it's at 25psi warm. My oil level is perfect, compression test scored perfect results, and my plugs were not oil covered or anything out of the ordinary. And today I cranked it and noticed there was less than 5pounds of pressure , I immediately cut it off. What's going on did my oil pump kick the bucket, anyone have ideas?

[KATwo40]

I'd check the pressure with a mechanical pressure gauge before assuming anything.

[1WheelWonder]

I checked it, and it showed about 2 pounds at idle.

[wild_maxx]

change your oil and try it again. How long has it been since your last oil change? I wouldnt be driving it.... you might destroy you motor.

[1WheelWonder]

I don't even have 1000 miles on this oil change, I will change it to see what's going on, I definately have not been driving it.

[NateDogg]

Can you verify the accuracy of the gauge on another car perhaps or try another gauge? Do you still have the stock pressure sensor? It will light up at 8psi or less.

[1WheelWonder]

I replaced the stock pressure gauge with the autometer unit, therefore I don't get a light. My valves tell me that my gauge is accurate.

[dontbugme]

If you're not hearing any unusual noises (knocking) that would indicate a spun bearing with increased clearances that are dumping the oil and your oil looks good, i.e., not diluted with fuel or water and your gauge is accurate I'd suspect you have a piece of crap under your oil pressure relief valve. If this is the case you could try dislodging it by temporarily changing to a higher oil viscosity and then, when cold, rev it up a bit to try and get the oil pressure high enough to unseat the valve and dislodge it. If this doesn't work it will mean removing the front timing cover to get at the oil pump relief valve, a huge pia. Hopefully, you find that the gage line is clogged or the gauge is bad.

[1WheelWonder]

It's a electrical gauge, i'm going to change the oil pump over the weekend and hopefully that will fix it.

[dontbugme]

I hope you have a FSM, because on these engines the oil pump's built in to the front timing cover, you'll need to buy the whole thing. If you're running an filter and haven't added a cup of sand to your oil there should be no reason that the oil pump's bad. Since you're planning on dropping the sump and removing the front timing cover. I'd suggest you get a set of feeler gages and measure the clearances you have on this pump. If you haven't bottomed out and pushed the pan into the oil pump pickup and the clearances are o.k., check the relief valve. 170K miles is a lot but don't forget the pump is oil lubricated. Good luck!

<Edit to fix punctuation error>

[1WheelWonder]

What is this check relief valve you speak of, do you think that's the problem?

[1WheelWonder]

Im running a 10w 30 oil now what would you suggest I run to try to dislodge any stuck funk?

[dontbugme]

I'd still try a mechanical gage as I don't trust electric ones.

The oil pressure relief valve is built into the high pressure side of the oil pump housing. It's a spring loaded spool valve with tight clearances that prevents excessive oil pressure when the oil is cold. Since you have some oil pressure, although weak, I'm assuming the oil pick up tube hasn't become detached from the pump. The fact that you had less oil pressure when you started it cold, the day after you noticed the drop in pressure, could mean the cold oil pushed the relief valve open even more and is stuck in the bore. I don't think anything is stuck under the seat so thicker oil won't help.

You can gain access to the relief valve w/o having to remove the front timing cover, IIRC, though you'll have to drop the oil pan. The valve's held in by a by a round screw and spring. If it drops right out, it's not stuck, check the flat face of the valve and seat for and gouges, chips or cracks. Then check or change the spring that holds the valve closed to see if it has the right tension, free length etc.

While you have the pan off, make sure none of the piston oil squirters fell or broke off or that the crankshaft oil galley plugs on the foward and after end of crank throws No. 1 & 4, respectively haven't fallen out. Both of these scenarios are highly unlikely but easy enough to check. Also, check your con rod bearing clearances by trying to move the big ends on the crank up and down or left to right, you really shouldn't be able to move them but a few thousands of an inch and since you didn't hear any knocking I doubt this is the problem.

If none of these checks leads to anything, maybe it is your pump.

[1WheelWonder]

When I removed my oil pan to tap it for my oil return line I did disconnect the oil pick up tube, and I couldn't find a gasket anywhere to replace it, so I used permetex. I had a slight feeling this would cause a problem done the road. What do you think the odds are that my make shift silicon gasket failed.

[steve s14]

it's a possiblity but it would not be my first guess. i would recommend double checking the pressure like other people have suggested.if the silicone had broken loose, it would normally flow up and be trapped by the filter but it could get stuck in the pressure regulator and cause the oil pressure to be too high or too low if it jammed up the plunger in the regulator.

[dontbugme]

When I removed my oil pan to tap it for my oil return line I did disconnect the oil pick up tube, and I couldn't find a gasket anywhere to replace it, so I used permetex. I had a slight feeling this would cause a problem done the road. What do you think the odds are that my make shift silicon gasket failed.

There's a reason Nissan is an almost a gasketless engine. And, when it is called for, it specifies what should be used and how much. It's a very common mistake to use too much of this stuff or the wrong composition. This stuff can be bad news if directions aren't followed explicitly. Goop it on too heavily or not have the surfaces perfectly oil free and yes, it could end up anywhere and in all the wrong places. In all likelyhood, you may have created your own problem. Live and learn, fortunately it doesn't sound like you did any major damage as you were wise enough to keep an eye on your gauge. Usually those 'first' feelings you mentioned should be dealt with as they are usually correct and impatience has led to many of us getting bitten in the a**. Even the most experienced of us makes mistakes - the key is in to not repeat them.

Let us know how it goes once you drop the pan.

[1WheelWonder]

Dontbugme you seem very knowledgeable upon advanced engine problems, are you a Nissan tech or someone like that? In effort to avoid dropping the pan I changed the oil today to no luck, and also disconnected my oil feed line to the turbo to see if any oil was pumping through but there was not a drop. So it looks like Sunday or Monday I will drop the pan and check my pick up tube and oil pressure relief valve. I appreciate every ones suggestions and helpful advice, thanks a lot.

[dontbugme]

No, I'm not a Nissan tech, just an old fart whose been working on all kinds of engines all my life and outside of EFI and the resulting computers, there really hasn't been any remarkable changes in engine designs in the last 100 years (no, I'm not that old!) I read a lot and my gift has always been mechanical aptitude. I grew up working on engines and cars and find it enjoyable to help the younger people today who are just starting to discover the joys and heartbreaks of getting the most out of their cars.

[TheOne]

you know, that must be why 1 of my engines blew, i believe i took out the pick up tube and never did replace a gasket in there, revved to 6k rpm, oil light came on and spun a bearing.

[1WheelWonder]

Well like I said, Monday came (today), I dropped the pan and took a look around. I checked for play in the crank and rods and that was good. I unscrewed the oil pressure relief valve and inspected it to the best of my knowledge, which seemed ok aswell. I also pulled the oil pickup tube that I had previously used permetex on. Apparently when I torqued it down the first time it pushed all of the permetex off of the contact area of two surfaces leaving me gasketless. I got a new o-ring from Carquest today and replaced my terrible silicon gasket. After reinstalling everything I fired her up (forgot to prime it) and it took her about 5 seconds to build pressure, but oil pressure returned to normal. I don't know if this is normal but before this incident oil pressure wouldn't rise with only a rev at idle but would rise with a load, now it will rise while revving and builds about a extra 10psi during a wot. Is that normal. I really appreciate everyone's helpful inputs, thanks.

[steve s14]

sounds normal to me but without an actual number, it's hard to tell.anyhow, glad to hear you got it fixed!

[1WheelWonder]

It has been 5 days since fixing this problem and everything is doing ok. During wot oil pressure goes to around 70psi and idles around 15psi and this is when it's fully warmed up.

[kapower06]

That all seems normal except you said that it changes with load. Oil pressure should not change noticably with a load on the motor. My first 2 ka's blew and one of the things I noticed was that the oil pressure would drop/rise slightly if load was increased or decreased. I swapped in a CA18 motor and the oil pressure never changes except from hot-cold pressures. Not trying to scare you but be careful and keep an eye on that gauge, or else it was a waste of $60 .

[1WheelWonder]

Thanks kapower06, I noticed your from St. Louis that's where I was born and lived for 10 years until moving down south.

[dontbugme]

It has been 5 days since fixing this problem and everything is doing ok. During wot oil pressure goes to around 70psi and idles around 15psi and this is when it's fully warmed up.

This is perfectly normal. The oil pump is a positive displacement type meaning it displaces a certain volume of oil for each revolution. Since the volume of your clearances and passages remain constant, the faster the engine revs, the more oil is displaced and the pressure builds because you now have more oil going into the same space.

Glad it worked out for you.

[1WheelWonder]

Thanks Dontbugme you were a big help.

[sil80drifter]

That's so funny. I did the EXACT same thing. Used liquid sealant on the oil pickup. Didn't figure it out til I thought the block was cracked and pulled the engine. Oil pressure was down for no reason. I've tried different oil pumps, springs, shimming, etc. You can't imagine how pissed I was when I swapped engines and realized all I had to do was put in the OEM o-ring. Live and learn. Good luck and hope all works out for you.

sil80
Modified by sil80drifter at 9:30 PM 5/16/2006