Oil light goes on under 1000rpm

[chewybtc]

So I was hoping to get some opinions on here about my oil light problem. I have a 97 limited with about 144k on it. I just had my head gasket go a couple weeks ago and decided to get a JDM engine and swap it. Everything went smooth with the swap and my mechanic friend changed the timing belt and water pump on the JDM while it was out of the truck. He said it probably wasn't needed because the JDM looked to be a 2000 motor with very low miles.

He changed the oil pan and the pick up along with the sender unit from my old engine (which I never had the oil light go on, ever) I drove it home about 25 minutes and never saw the oil light come on. I drove it for the first time the other day and when I started it up the oil light came on. I checked the oil level and everything was full and clean.

After talking to my mechanic we tried a couple things and determined the light only comes on when the truck is under 1000rpm. I can be rolling or sitting still, but if rpm goes under 1000 it comes on, if it goes over 1000rpm the light goes off.

I get no check engine light just the oil light. It runs great and idles perfectly at 700rpm.

Anyone have any suggestions please?

Thanks!

 

[LittleCaesar]

I have to ask why the mechanic didn't put a mechanical gauge on the block to see what values could be achieved.

Are you using the JDM sending unit?

 

[chewybtc]

I have to ask why the mechanic didn't put a mechanical gauge on the block to see what values can be achieved.

Are you using the JDM sending unit?

That's what he said as well about the gauge, but I'm 30 minutes away and he is swamped, and I don't drive the truck that much, so I thought I would ask on here.

No he said he swapped the oil pan, pick up, and sending unit from my old engine.

 

[chewybtc]

Anyone have any other thoughts on why this would be doing this?

 

[jeremyc74]

You really have to determine whether this is an actual low pressure condition, or if it's just an indication problem before you can go any further, and that means putting an oil pressure gage on it.

 

[chewybtc]

You really have to determine whether this is an actual low pressure condition, or if it's just an indication problem before you can go any further, and that means putting an oil pressure gage on it.

Yeah I am texting my mechanic now to see when I can get in there to do the gauge test, will let you guys know what we find.

 

[LittleCaesar]

Once you get an idea of how the oil pressure is at idle after the oil is up to temp, then you can get an idea of either the low end possibly being in need of a rebuild, or if you hear nothing and the readings are strong, then it may be an issue with the sending unit itself.

How did it look under the valve covers of the JDM engine? Clean? Dirty/Sludge?

 

[nevada]

Yeah I am texting my mechanic now to see when I can get in there to do the gauge test, will let you guys know what we find.

was there any change in the weight of oil used when the new engine was installed?

as said, you really need to know what the actual pressure is.
it would also be good to know at what exact pressure the light goes off.

I know that on some engines, its not uncommon for the oil light to be on/flicker at an idle. they run 5-7 psi at idle.


if I were you, regardless of what you come up with, id have a mechanical oil pressure gauge installed. then there is no question later down the road...

 

[chewybtc]

I'm waiting to hear back on when i can get him to do the gauge test.

Do you guys think running sea foam or something like it would be a good idea?

Is there a "proper" way to do it?

What about that Lucas Oil Treatment?

 

[chewybtc]

was there any change in the weight of oil used when the new engine was installed?

as said, you really need to know what the actual pressure is.
it would also be good to know at what exact pressure the light goes off.

I know that on some engines, its not uncommon for the oil light to be on/flicker at an idle. they run 5-7 psi at idle.


if I were you, regardless of what you come up with, id have a mechanical oil pressure gauge installed. then there is no question later down the road...

I used to use Amsoil in my old engine, and when we put the JDM engine in we swamped my old sender, pick up and pan (and oil cooler). We put regular oil in so i could run it a couple hundred miles and then change the oil to Amsoil.

 

[slides]

try seafoam, not sure if it will do anything or not but i smoked out my entier street when i did it. Use the hose that connects to the PVC valve.

 

[02SE]

Sucking Seafoam into the intake manifold, will do nothing for engine oil pressure.

As LittleCaesar said, you need to know what the actual oil pressure is, before you (or your Mechanic) can make an informed decision as to how to proceed.

 

[Blitzkrieg]

Pull your oil pressure sensor and check it first. Make sure it does not have crap/debris from the motor work on the sensor or the pilot hole leading to it. Sloppy scraping of the old head gasket and....

And I agree with the above posts stating mechanical gauge test. Rule in or out that you have or don't have a pressure problem first. Then work back.

 

[scrap metal]

One thing to consider is oil pressure is greater when the engine is cold. Does the light come on starting it from cold ( parked overnight) or just once the engine oil is warmed up and the pressure drops?

 

[chewybtc]

One thing to consider is oil pressure is greater when the engine is cold. Does the light come on starting it from cold ( parked overnight) or just once the engine oil is warmed up and the pressure drops?

Yesterday i tried exactly that, i wanted to see if the light would come on right at start up.

My driveway is on a slight incline by the way.

I started it up and didn't touch the throttle. I didn't see the light on, and I wanted to get some ice off the window, so i started doing that and the engine just stalled out. It was running maybe 15 seconds, then stalled and sounded pretty bad, almost like it was seizing or something.

I started it back up and kept the RPM over 1000 and it ran perfect and no light. I backed it out into the street where it was level and as soon as the RPM came down under 1000 the light went back on.

My mechanic can't get me in until next week to check it with a gauge. He suggested putting Lucas Oil treatment in. But i thought I shouldn't do it until we get the gauge on to see the pressure without anything in the oil.

Thanks everyone for the thoughts, its driving me crazy because it ran so nice, and still does, except this oil light problem.

The JDM engine has a 90 day warranty but it only covers internal stuff, the oil pump is not going to be covered.

It's just weird that i never had a problem on my '97 engine and he used all those parts (except the oil pump).

He did tell me they thought the engine was a 2000, would that be any reason this would be happening, using my '97 parts on a 2000 engine?

 

[chewybtc]

Sucking Seafoam into the intake manifold, will do nothing for engine oil pressure.

As LittleCaesar said, you need to know what the actual oil pressure is, before you (or your Mechanic) can make an informed decision as to how to proceed.

Yeah I figured that, maybe he meant in the oil. LOL I was going to do the sea foam treatment (gas tank, intake, oil) as I don't know how well the JDM was maintained and thought i would give it a good cleaning before I switched it over to Amsoil synthetic. ( I don't put many miles on this truck..maybe 7k a year)

But now with this oil light issue I want to get that worked out first. Then do the sea foam cleaning process.

 

[nevada]

Yesterday i tried exactly that, i wanted to see if the light would come on right at start up.

My driveway is on a slight incline by the way.

I started it up and didn't touch the throttle. I didn't see the light on, and I wanted to get some ice off the window, so i started doing that and the engine just stalled out. It was running maybe 15 seconds, then stalled and sounded pretty bad, almost like it was seizing or something.

I started it back up and kept the RPM over 1000 and it ran perfect and no light. I backed it out into the street where it was level and as soon as the RPM came down under 1000 the light went back on.

My mechanic can't get me in until next week to check it with a gauge. He suggested putting Lucas Oil treatment in. But i thought I shouldn't do it until we get the gauge on to see the pressure without anything in the oil.

Thanks everyone for the thoughts, its driving me crazy because it ran so nice, and still does, except this oil light problem.

The JDM engine has a 90 day warranty but it only covers internal stuff, the oil pump is not going to be covered.

It's just weird that i never had a problem on my '97 engine and he used all those parts (except the oil pump).
He did tell me they thought the engine was a 2000, would that be any reason this would be happening, using my '97 parts on a 2000 engine?

i would certainly hope the warranty covers the oil pump.
oil pressure is hard to check without running the engine. so you basically have to install it first, then check it. if its bad, and the engine is running with low/no oil pressure, it wont last long and is basically junk...



I wouldn't even start it again until you get a mechanical gauge on there and verify it even has oil pressure.


honestly in my opinion, I would be planning to replace that engine....

 

[Kenworth]

Hey Erik here,how's it going wheels and tires left today.pulling your spare engine
Sat?... No really if u still have interest in frame most likely 2/3 if weather go ok
Body will be off ,on to your engine oil pressure why don't you change oil with fresh oil and give it a go, jdm came a long way who know what kind of crap was inside motor that got rinsed out could of thinned oil out,give that a try

 

[chewybtc]

Hey Erik here,how's it going wheels and tires left today.pulling your spare engine
Sat?... No really if u still have interest in frame most likely 2/3 if weather go ok
Body will be off ,on to your engine oil pressure why don't you change oil with fresh oil and give it a go, jdm came a long way who know what kind of crap was inside motor that got rinsed out could of thinned oil out,give that a try

Glad you got those wheels sold, and yeah your a funny guy (my spare engine)!! Don't even joke!! LOL

Yeah i am 100% on the frame, you just let me know what's up and when and what i can do to help if you need it.

Yeah I'm not driving it until my guy can get me in next week to put a gauge on it and see what's up. Then i thought about running sea foam in the oil for a couple minutes right before dropping the oil and then checking the gauge again.

Any thoughts on that plan?

 

[Kenworth]

I would just drop oil and replace with fresh oil ,not alot of money
And if you think about it,possible they put crap in those Motors to prohibit rust
Long trip from japan to here .like cosmolene or something ,