Damn it....

[oldschool90]

So...I have this odd oil light issue. I go to start up my truck, the light comes on initially then turns off after a couple seconds (like it should). But then after a few minutes, It starts to come on again. At first, it's at a low rpm, then comes on at gradually higher rpms, then comes on at gradually lower rpms. After the truck is driven for 5-6 minutes, it doesn't come on again. This (usually) only happens when the engine is started cold. And sometimes after the truck is fully warm, the light will kinda flicker at idle (but only sometimes). I am currently running 10w-40 with an almost full bottle of that Lucas oil stabilizer stuff, and the oil level is almost at the full mark. We've been getting some pretty cold nights here (last night was 14 deg.) and the highs are about 50-60. I have noticed that the motor is losing some oil, and it seems to get worse the lower it is, and when I fill it up (with the 10w-40), it doesnt do it as bad. I JUST got done putting a new crank in (for the second time now) and I really don't want to have to do that again.

 

Here are some (shitty) videos of whats happening:

 

 

While I'm driving (engine cold)

 

 

At idle (engine warm)

[Radiant-Designer]

could it just be an oil pressure switch??? (maybe thats even where its leaking from)

[Eagle_Adam]

could it just be an oil pressure switch??? (maybe thats even where its leaking from)

 

XXXX 2 ^^^^

 

 

I just got done with a similar issue on my brothers 620, the light would come on randomly and then go off. I pulled the oil pressure sending unit and got a new one for $5 or so then cleaned the 1 wire connection. Problem solved :cool: and the one of the oil leaks was solved too. (the other was the cam cover gasket - fixed mow:P)

[DOnatello]

could be an oil pressure switch or possibly an oil pump problem. Since the pump is super easy to get to and you should really drain out the junk lucas anyways, pop the oil pump off and inspect it. You can always add an ugraded pump spring for higher pressure, wolf creek racing sells one for 40$. replacing the switch is super easy and a common repair on these engines.

[RedBanner]

I was thinking the same, any chance you have a mechanical gauge sitting around? I has one we could hook up and see what it says, or there real cheap ones every where. Could be the pump but idt it would "kinda" work , could always do the z pump/spray bar upgrade :cool:

[datzenmike]

The switch is designed to come on between 5-8 PSI. I can see that at idle warm thin oil and the added load of a spray bar... but... no way would it do that when revved up on the highway.

 

So first swap in a $15 sender from the dealer or pocket one from the junk yard. Any L series motor or 720 2wd will do. Use a wrench to remove and tighten it on and not vice grips. That will bugger them.

 

If you are running a spray bar it would be insane not to replace the oil pump with a high volume output pump from a KA24E (240sx or KA24E and DE from a D-21 Hardbody. My hot idle pressure went from 17 to 29 PSI with no other change but a very used KA pump installed. Just friggin' do it!

 

The Z24i in the Hardbody, LD28 diesel in the Maxima and the 280zx turbo automatic also has them.

[oldschool90]

I know it's not the switch. I have somewhat recently replaced it with a new one and also when the light comes on this ticking noise starts and goes away when the light goes off. It's like a valve tick but a little different which I'm guessing is the crank bearings :(

 

So mike, you say an oil pump from a d21 with the ka24e AND de will work? I was told not to get one from the de.

[datzenmike]

The later 240sx DE has an internal pump but both the E and DE in the Hardbody are external, just like the L series. The differences are totally internal so don't expect to tell by looking on the outside.

 

Know what to look for if buying new. It would be easy to get one in the wrong box or from someone who thinks it's a high volume pump. Here's how .... (but it has to be removed or in a box)

 

The pump is of the trochoid type with internal rotors. The high volume output rotors are 14% longer and the housing is machined deeper to accommodate them.

 

 

When assembled, you can look down into the inlet port and see that the top of the longer (taller) rotor is much easier to see.

 

This is a regular L or Z series 4 or 6 cylinder oil pump. The top of the rotor is just barely visible...

 

Here the difference is very obvious with the taller rotor slightly above the port edge.

 

 

Memorize what the high volume one looks like and good hunting. I have one on all my L or Z engines. Silly not to really. The pressure is close to the same but there is more volume per turn so low RPMs have more pressure. Great if you have a spray bar or your engine has some wear and the pressure is low anyway.

.

[datzenmike]

I know it's not the switch. I have somewhat recently replaced it with a new one and also when the light comes on this ticking noise starts and goes away when the light goes off. It's like a valve tick but a little different which I'm guessing is the crank bearings :(

 

So mike, you say an oil pump from a d21 with the ka24e AND de will work? I was told not to get one from the de.

 

The sender works by grounding the wire to it. If it's being pinched somewhere it will come on randomly. BUT you say it makes a sound. This is very scary as maybe the pressure really is fluctuating. This could cause severe damage. I wouldn't drive it until you are sure it's getting lots of oil.

 

Even cranking speed should shut the light off. Mine does. When you stop, 4-5 seconds later the pressure drops and on it comes.

 

Just thought of something... maybe the pressure relief valve spring is broken or the piston sticks open. An oil pressure gauge would sure help here.

[oldschool90]

Well I've got one more day of work which I have to drive to and from with it (unavoidable), but on Saturday I'll hit up the junkyards and look for a pump. Hopefully I find something.

 

I had a cheapo HF mechanical oil gauge on it once, but the damn oil line kept getting air in it so I just took it out and trashed it.

 

And thanks for the oics mike, I have always wondered how they got more flow from the same size pump.

 

Oh, and what's wrong with the Lucas stuff?

[q-tip]

the lucas stuff makes the oil thicker and puts in some extra additives, its not bad just might not be what you want to run

[oldschool90]

its not bad

 

It was referred to as "junk". Just wondering why.

[datzenmike]

 

I had a cheapo HF mechanical oil gauge on it once, but the damn oil line kept getting air in it so I just took it out and trashed it.

 

 

Air r trapped in the line won't affect it's operation. The air will compress to 50PSI or what ever the output is. 50 psi of air or 50 PSI of oil... the same.

[oldschool90]

Air r trapped in the line won't affect it's operation. The air will compress to 50PSI or what ever the output is. 50 psi of air or 50 PSI of oil... the same.

 

Interesting... but then why do you think it worked better after I bled the line? It usually didn't read much of anything with air in the line, but after I bled it, it read a higher psi. And it was usually more air than oil (not sure how that was happening)

[kelrich]

Maybe your oil pick up is getting clogged? Loose mains maybe?

[DOnatello]

Make sure you run that oil pump by mikes damage sniffing dog. One sniff and he can tell you exactly whats going on!! :D

[oldschool90]

Yeah when I pull it off I'll disassemble it and post some oics up. But it won't be till tomorrow.

[I'm BLUE]

Curious !!! ,,,Back to the beggining ... why were you putting (2) seperate cranks ? ( was it knocking ? High-Mileage Engine ? Bad Bearing ? )

 

(1) I would defintely replace or check/reseal the oil pressure sending units ( cheapy aftermarkets ,,, can read different PSI's ,,, depending on quality/manufacturer ,,, already good advice to hook up a seperate mechanical gauge ,,, go to the hardware store and get a brass T-Fitting ,,, that lets you have both gauges hooked up at once ,,,

 

(2) MAybe un-related ,,, Never Use Fram Oil Filters !!!

 

(3) Do you have your old Oil Filter(s) ,,, possibly ,,, from past times you have had this issue ,,, and when changing crank out (2) previous times ? If so ,,, cut the suckers open ,,, and look for shavings ( if your so-inclined or feel up to the task ) ,,,

 

(4) Is your head getting enough lubricant ? ( IE: pull off valve cover ,,, should be sufficient amount of oil bathed ,,, if not ,,, oil passages/pump/pickup problems )

 

(5) I assume you replaced the oil seals with new ones ,,,( front main ,,, rear main ,,, ) and all other oil seals are good yes ? ,,,

 

Did you have the crank machined/polished before re-installing ? ( or did they look ok ? ) your oil passages clear in connecting rods ?

 

(6) High Volume pump is definetly a good idea ,,, but if your old one was not properly primed ,,, those metal shavings have to go somewhere ya know ? :unsure: ,,,

 

(7) Please don't have music blasting on your videos that you need help with diagnosing (hearing ticks/engine/etc) ,,, thx ,,, :lol: :P

 

All of the advice is above my reply is good !!

[oldschool90]

Curious !!! ,,,Back to the beggining ... why were you putting (2) seperate cranks ? ( was it knocking ? High-Mileage Engine ? Bad Bearing ? )

 

The first one was about a year or so ago and what happened was it had the 30 year old oil pressure switch on it and it wasn't working so the truck ran out of oil and the one of the bearings got hot and welded itself to the crank and connecting rod.

 

The second one was because I had some crazy complicated setup when I installed the new switch along with the cheapo HF gauge so it wasn't properly grounded. So the truck runs out of oil again and starts knocking really bad. My dad just threw some oil in it and it was OK after that with a slight knock. We eventually changed out the rod bearings for new ones but the crank had a spot on it where it had a very small groove on it. decided to continue and just replace the bearings, but the knock came back, along with this oil issue. So we replaced the crank a second time.

 

(1) I would defintely replace or check/reseal the oil pressure sending units ( cheapy aftermarkets ,,, can read different PSI's ,,, depending on quality/manufacturer ,,, already good advice to hook up a seperate mechanical gauge ,,, go to the hardware store and get a brass T-Fitting ,,, that lets you have both gauges hooked up at once ,,,

 

Yeah, but like I said, there's a noise when the light comes on and goes away when the light goes off, so I know it's not the switch.

 

(2) MAybe un-related ,,, Never Use Fram Oil Filters !!!

 

I haven't let that shit touch my truck since I started taking over the repairs. Been using STP (Not sure if it's better, but it's not fram ).

 

(3) Do you have your old Oil Filter(s) ,,, possibly ,,, from past times you have had this issue ,,, and when changing crank out (2) previous times ? If so ,,, cut the suckers open ,,, and look for shavings ( if your so-inclined or feel up to the task ) ,,,

 

I have the one from the last crank we replaced, and I also still have the crank and bearings that go with it (I just finished putting this one on last week). The odd thing is is that none of the bearings are even remotely damaged. One has what looks like a wear mark but they look like they're new.

 

(4) Is your head getting enough lubricant ? ( IE: pull off valve cover ,,, should be sufficient amount of oil bathed ,,, if not ,,, oil passages/pump/pickup problems )

 

I spoze if I must, I'll go pull the valve cover off and look.

[oldschool90]

(5) I assume you replaced the oil seals with new ones ,,,( front main ,,, rear main ,,, ) and all other oil seals are good yes ? ,,,

 

Yes. Ordered a kit that had almost all the seals and gaskets that I needed.

 

Did you have the crank machined/polished before re-installing ? ( or did they look ok ? ) your oil passages clear in connecting rods ?

 

Both cranks were re-manufactured, and I'll be honest, other than blowing out the oil passages and thoroughly wiping them down, I just threw them in there. I did use assembly lube on the bearings though and everything torqued/double checked

 

(6) High Volume pump is definetly a good idea ,,, but if your old one was not properly primed ,,, those metal shavings have to go somewhere ya know ? :unsure: ,,,

 

The old one was drained and filled with oil prior to installation. Before start up, I primed the oil system by removing spark plugs, grounding the coils, fuel system disabled and then turning the engine over in short bursts till the oil light went out, indicating oil pressure.

 

(7) Please don't have music blasting on your videos that you need help with diagnosing (hearing ticks/engine/etc) ,,, thx ,,, :lol: :P

 

Yes, normally thats a good idea, but I wasn't trying to get the noise. It was to get the oil light. And besides, the sound is kinda quiet and my truck is really loud, so there's no way I would have been able to get the noise anyways. AND on that particular night, the noise wasn't there. (Of course. But maybe a good thing)

If you want, I can get a better video today and I won't have the music blasting . I guess I'll do it anyways because the ones I have are pretty shitty quality from being at night.

 

All of the advice is above my reply is good !!

All of the advice above my reply is good!!

Fixed

[datzenmike]

The first one was about a year or so ago and what happened was it had the 30 year old oil pressure switch on it and it wasn't working so the truck ran out of oil and the one of the bearings got hot and welded itself to the crank and connecting rod.

 

The oil light is designed to come on when the key is turned on to prove that the low pressure light is working. If you knew that it wasn't working didn't you check the oil level now and then??

 

 

The second one was because I had some crazy complicated setup when I installed the new switch along with the cheapo HF gauge so it wasn't properly grounded. So the truck runs out of oil again and starts knocking really bad. My dad just threw some oil in it and it was OK after that with a slight knock. We eventually changed out the rod bearings for new ones but the crank had a spot on it where it had a very small groove on it. decided to continue and just replace the bearings, but the knock came back, along with this oil issue. So we replaced the crank a second time.

 

Again after the first disaster, wouldn't you check the oil level even more often??? I know this doesnt help but... wtf?

[oldschool90]

The oil light is designed to come on when the key is turned on to prove that the low pressure light is working. If you knew that it wasn't working didn't you check the oil level now and then??

 

I Knew it wasn't working, but I wasn't the one driving it at the time. My dad was using it for work (and I think he knew it wasn't working either). And we did check the oil level almost every time we used it because it was using a lot of it.

 

Again after the first disaster, wouldn't you check the oil level even more often??? I know this doesnt help but... wtf?

 

Yes, yes. I think if I remember correctly, I meant to check it that day but my dad took off for work before I was able to check it.

 

I don't really blame anyone for the first time it happened. The truck was using/leaking oil like crazy and we were checking it almost every day.

 

The second time I blame myself for because of the stupid crazy setup I had to make the oil light and mechanical gauge work together. I knew the light didn't work and I did nothing about it. And the truck wasn't using as much oil as it was so I guess we got a little lazy in checking it, but it was still checked somewhat often. But not often enough I guess

[Z-train]

Trace the sender wire to make sure it's not grounding on something.

[oldschool90]

So given the situation I just decided to get a new pump from autozone. I don't think I would've had time to go out to the junkyards, and I kinda doubt I would've found one anyways. I ordered one for a 92 Nissan D21 2.4L, and picked it up for 80 bucks and installed it today. So far everythings' looking good. No oil light on yet, but the engine wasn't cold either. Guess we'll see how it's workin tonight after work!

 

Some oics:

 

 

 

 

 

 

 

 

 

you should really drain out the junk lucas anyways

 

Still wondering why you think it's junk.

[Boaty]

Hey now, don't be bashing that Lucas Oil Stabilizer too much. Stuff actually does it's job well.

If I had a higher mileage L motor, I'd probably use it too.