Oil pressure drop on 4AGE smallport after oil and filter change

[BoostBoy]

Yep sorry, old one was Z442. I do have a remote oil filter setup....makes changing the filters a really easy job...anyway now I have the Z386 fitted on.

Okay, so here's what happened...started the car checked for leaks...noticed a drop straight away...checked and looked like it was coming from the same spot. Cleaned it up...started the car again...let it idle for a few more minutes....this time no oil.

I took the car around the block, gave it a few revs....came back home...checked it again and no oil. I'm thinking the first bit of oil was just some residual oil from the previous leak....but it doesn't seem to be leaking anymore which is great news!

Bad news however is that the needle on the Oil pressure gauge is still in the same spot...about a centimetre above the lowest point, when it used to be half-way! Also when I accelerate the pressure should increase, but it stays in the same spot. I can't figure it out...I have no oil leaks, filter is smaller, car sounds the same and there's no loss in power....can't work it out...maybe the gauge is faulty??

[Hiro]

If you have a remote filter it doesn't really matter _what_ filter you use, as long as it matches your remote housing. Filter size doesn't have that great an effect on oil pressure.

[BoostBoy]

What about this scenario....is it possible with the remote Oil filter setup, and redirecting the oil cooler lines that the Oil pressure on the factory gauge would show a decrease in pressure? Or should the pressure always be the same?

Like I said it was half-way before with the same setup...change oil and oil filter, and now it's low...maybe because the oil is new? Would that be a common thing?

[LeeRoy]

I'd say your gauge is stuffed. Mine upon startup sits at about 1/4 but once you start driving it goes to 1/2 and no lower, or higher depending on rpm. It just did this one day and I hadn't changed anything iirc.

However, the epitrochoid (the thing in your oil pump) might be dying. Generally they get to a point of wear that once you reach that point, the tolerance between the pump and the gear becomes large enough that a significant drop in pressure occurs. This might have occured long ago and the thinner oil your now using is not 'filling the gaps' so to speak.

[fixeruperer]

you know what im gonna say dont ya.

[BoostBoy]

Haha yep yep...get an oil pressure gauge...my next door neighbour might have one. But okay, just say that confirms I have an oil pressure drop...what next? All my lines are good and I don't think it's my oil pump because that was reco'd when I got the engine built??

Seems like a strange coincidence that my gauge stops working correctly after an oil change. Would even the slightest loosening of an oil line cause such a drop?

[BoostBoy]

Interesting...I just read the repair manual I downloaded...apparently low quality oil can cause a drop in oil pressure....I wonder if that's the cause of my pressure drop?? hmmm....very close to buying some better oil tomorrow and replacing it!

Just a matter of what oil for a 30,000k 4agte....I want to go with Penrite...but full-synthetic, semi-synthetic, HPR15, HPR30??? Arrggh doing my head in....

[Bananaman]

i have used a 3sgte one and fit the same thread as the z386 one

Not sure what the number is for the 3sgte one but it was larger in length.

Not going to offer your opinions on oil in your 4AGTE? I hear there is some high tech science behind your choice

[fixeruperer]

to have an oil leak to leak enough to show on the gauge, you would have quite the mess.
if the gauge shows low pressure, theres a few things to look at like pickup, pump (pressure relief valve), oil squiters etc.

dont message back untill you have oil pressure numbers

[BoostBoy]

I dunno mate...I'm not sure I can even get to the oil pressure sender gauge! I'm trying to look at it from a logical point-of-view...if all I've done is change the oil and the oil filter...then maybe one of these things is affecting the pressure? I know it's not the filter....so maybe it's the oil?

Can a shit grade oil have this affect? I've read it maybe can. I think GTX3 is shit! What would shit me even more is if I buy Penrite tomorrow, change the oil and still the same thing...i'm tempted to still do it though...

Actually, come to think of it, I did remove the Oil Filter bracket to cleanup the oil...maybe something happened to the relief valve when I was cleaning it....like clogging it up? How do I inspect whether it's working or not?

[30psi 4agte]

Mabe its just a shit gauge or sender.Could be a coincident that the gauge shit its self when you changed oil.
The oil pressure needs to be checked with a mechanical gauge to confim this.

Bite the bullet and just do it.

[LeeRoy]

You should be able to pick up a gauge for not much more than new oil and a new filter will cost you.

[allencr]

...so maybe it's the oil? Can a shit grade oil have this affect? ...maybe something happened to the relief valve when I was cleaning it....like clogging it up? How do I inspect whether it's working or not?

No, unless you're running 60 in Antarctica or 0 in the Sahara.
Running with only 1 liter of oil can have a serious affect.
The relief valve will only open at high pressure, from cold thick oil and/or high RPM and when the oil pump & bearings are OK. If it is stuck open and/or isn't seating correctly, the oil pressure will be very low at idle and lower then normal at all other RPM.

[BoostBoy]

Okay here's an update...today I removed the Oil filter bracket, opened the nut where the relief valve sits...cleaned it all out, made sure it was seated correctly, and I dropped it in to see if it would slide down....all good. So that wasn't the problem.

Then started performing some tests on the gauge and sender...gauge passed all tests. Did the specified test in the manual for the sender...which is to connect the positive terminal on the battery to the sender through a 3.4W test light bulb. The light bulb should then flash when the engine is running...and do so more frequently as the RPM is built up.

I got one flash when I started the motor...and then nothing after that....so possibly the sender is gone...so in that case since I have to take it off and replace it, I'll also test the oil pressure while it's off, and hopefully the problem will be solved.

EDIT: If the oil sender is stuffed...what does that mean for the car? Just the gauge won't work or does it have an effect on anything else?

[abently]

Oil senders are not very expensive, well the non-genuine ones anyway so just replace it and see what the gauge then reads.

Yes low quality oil does show up as low pressure only once you've overheated it, so no don't change you oil 'cause that's not the issue.