Hi all,

i am a new user here on J-Bodies and i have tried to search for this but didnt find anything helpful.

i do not drive a cavalier, i do not own a GM. Me and my entire family have Toyotas and VW's so i am very new to the North American way of engine design. please dont think i am bashing anything, i respect all and strongly believe in people who try new things.

A bit of back ground on myself, i drive a JDM Yaris with many custom up grades. the biggest one, a complete engine rebuild and custom turbo (custom header, alot of first time done things). Im running it as my daily driver at 11 PSI and dyno'd its pushing 216hp at the wheels (not bad for a car that weighs just over a ton) i am a Electromechanical Engineer currently working as a Automation and robotics engineering design consultant.


Anyways, Recently i have been asked by a close family friend to take a look at her 2000 2.4L cavalier. spun bearing 1 and 3. i decided i would help out and replace the engine. i have a few connections so i found internals of a 2001 2.4L engine with 80km on it (yes 80km, not 80,000km) i got everything except the block and oil pan and oil pump (top end and pistions and crank)

engine is completely rebuilt and running like a Toyota, only issue is after she really gets warmed up oil light is on under 1500rpm. i called around and these oil pumps arnt cheap.

what i really want is a detailed picture of a 2.4L oil pump. mine seemed to have 2 holes on the bottom ( same side as oil pick up) and im not 100% sure they are suppose to be there. id love to buy an oil pressure gauge for it but they are not very cheap for a one time use thing.

is this a common issue and is there a easy fix? im running 10w30 oil also

oil pumps have always been a weak point of the 2.4's.. this contributes to the #3 rod bearing to fail (3 is most common) my 2.4 is at 130k with no issues... yet. but high rpm/high hp/boost etc.. usually don't use the stock pump. most people convert to the older 2.3 quad 4 pump, much better oiling.. but to do this requires parts from a 2.3, a different gear on the crank, more passages drilled into the 2.4 block, and some passages in the 2.4 block closed up. definitely not something to do with the motor in the car already..

i don't have a picture of a 2.4 pump, but from what I seen, there should be the oil pickup tube in the side of the pump casing.. pressure is fed through the pump into the block via holes on the bottom of the pump that line up with the galley passages in the block.

I would suspect that the original pump (that you re-used if I read correct?) has been the problem the whole time. I would try to get a different pump put in ASAP... also oil pressure gauges aren't that expensive if you just get a 0-100 psi gauge and fittings to make connections.. it doesn't have to be a fancy one. and i understand that a new pump wont be cheap as well.. but the pump is the heart of the motor.. without it the rest isn't gonna last...

there are also several posts about oil pressure in here if you do a forum search like "LD9 low oil pressure" and vary the wording, use LD9 and 2.4 since both terms are widely used..

This thread is recent from the performance section.. this is about a built turbo motor, but still has lots of info about oil pressure, and what a 2.4 needs to keep oiling effectively

http://www.j-body.org/forums/read.php?f=2&i=477577&t=477577

thanks for the reply,

yes its the original pump being used. i didnt really want to rip apart the bottom end of the motor again. also seeing as its just an engine rebuild for someones grandson to beat the piss out of, i dont think the effort to change over to the 2.3L oil pump is worth it.

also since the car isnt mine, its just chilling in my garage till i give it back. not a RUSH to get the car back so not a RUSH till i get a new oil pump. ill pick up an oil gauge and check back. any idea what the thread size and type are in the stock oil pressure gauge port?

also what is the best way to actually diagnose the pump or area's of wear inside the pump? GM wanted over 500 for a new oil pump. i dont think this car is worth that much.


also ive noticed there seems to be quite a bit of "blow-by" when you take off the oil cap. how normal is this? ive never noticed blow by on any other car ive worked on, could soemthing else be causing this pressure? if there a way to gauge how much blow-by is normal?

Not sure on blowby... i havent ever ran my car with the cap off to notice. As for a gauge you should be able to remove the sender for the dummy light from the back of the block/head to plug in a gauge. Should be 1/8 npt. Also you could try a parts store for a pump... considerably less for the same thing. I think i saw them on rock auto in the $100-150 range

def check the oil pressure. the thread on the cam tower where the factory sender is, is 1/4 " NPT. very useful tool to have for sure. Melling makes a good aftermarket pump for the 2.4 i used one in one of my motors and it worked as well as a factory style pump could be expected to work. they're cheap enough, if you cant find one of those though sealed power is a good enough brand. ~140 for one isnt a bad price.
if the motor spun both #1 and 3 rod bearings then that pump had a loooot of metal run through it and its shot. probably puttlng out real low oil pressure at hot idle. anything less than 10psi at hot idle is bad. it kinda sucks to have to drop the oil pan in car but its sounding a lot like it needs it.

hold up, first it was a 1/8 then a 1/4.....

im really not looking forward to pulling out the oil pan......

Thanks all for your help.

Lol its one or the other

Most 2.4l twin cam "ld9" motors spin rod bearing three from low oil levels. Not from a bad pump.

Unless you family member was spinning faster than redline. ....which I doubt greatly.

Rule of thumb for oil pressure on a ld9 is 10psi for every 1000 rpm once up to temperature. Also, you can disconnect the oil pressure sensor in the intake cam tower, and install a exteneral pressure gauge to see. The car will run fine with no sensor installed / plugged in, since it is a normally closed sensor.


Our oil pumps rarely go bad, unless the oil is never changed. I would go with a melling pump if you need to replace it.




PRND321 Till I DIE
Old Motor: 160whp & 152ft/lbs, 1/4 Mile 15.4 @88.2
M45 + LD9 + 4T40-E, GO GO GO

If its 10psi for every 1000 rpm then at idle it sees less then 10psi? No way.....

Also the oil in the car was rarely changed, its believed to have gone close to 40000km on an oil change

This is EXACTLY what is says in my 99 GM Factory Service Manuals....
Oil Pressure @ 3000 RPM, 30 psi min.
Oil Pressure @ 900 RPM, 10 psi min.

Replace oil pump if oil pressure if below either of the above levels, once the vehicle is up to operating temperature.










PRND321 Till I DIE
Old Motor: 160whp & 152ft/lbs, 1/4 Mile 15.4 @88.2
M45 + LD9 + 4T40-E, GO GO GO

What he said... my beretta with the 2.8 v6 only called for like 6psi at idle at operating temp.

Today I was looking at the hole balance shaft assembly. I noticed a small hole about the size of a pin head on the inside wall of the oil pump intake. This hole leads to a bolt hole right beside it, from there it has no use from what i can see. I'm wondering if I plug this hole if it will help gain some oil pressure and maybe even with the "cavitation" issue.

-MD- Enforcer wrote:Most 2.4l twin cam "ld9" motors spin rod bearing three from low oil levels. Not from a bad pump.

Our oil pumps rarely go bad, unless the oil is never changed. I would go with a melling pump if you need to replace it.

Thank you for bringing these points out.
I would like to add that it will take 4.5qrts of oil after a filter & oil change, NOT 4qrts like GM has misprinted. Monitor the oil and top off if need be.



>>>For Sale? Clicky!<<<
-----The orginal Mr.Goodwrench on the JBO since 11/99-----

Sorry for the long delay, here is a picture of oil pump, please advise if it looks normal. i hate this design and plan to replace.

Also i tested pressure and it was close to 5psi or under at warmer idle, not even hot.

Please notice 2 "extra" holes on right side of oil pick up, are these normal?

so im realizing now that the oil pump is just the little silver part on that housing....... this system is odd. i did get a new oil pump (was hoping for the entire unit) so i will install shortly and see how that goes.