siboby4

Hey Guys,
I'm new to the forum, recently purchased a 93 4runner, 175k miles but supposedly engine was replaced @ 127k with reman.
When starting and driving cold engine the oil pressure seems to be a good reading but after engine warms the oil presure drops significantly to where cruising at 3000 rpm pressure is very low, no light comes on. I was thinking about replacing oil pump, but wanted to get some opinions.

Also, has anybody swapped a 3.4L V6 into a 2nd gen 4runner or truck, can it be done ?? Drop in swap maybe ??

Thanks for any info,

Bob

Nodlew505

Siboby4--welcome to the forum. I have a 1993 as well, and I have noticed the same thing occuring. Oil level is good, the needle just drops as I drive, so I am curious to see what others opinions are.

Regarding the 3.4 swap, the following link from Pirate 4x4 has the process spelled out quite nicely.

http://www.pirate4x4.com/forum/showt...hreadid=137361

sandcrawler

i have a 93 2nd gen, too. 116k on the orig. engine. when i start it up the oil pressure is just a hair to the left of the 3/4 mark, but then as i drive it slowly slides back down to the "low"/1/4 or so mark. i have heard similarly from other owners and have been told that this is ok. i just check my oil religiously to do a reality check.

i'm also using mobil 1 10w30 full synth and i hear that the higher flow rate of the stuff translates into lower oil pressure.

REDYOTA

I have the exact same problem but mine is a lil worse along with the low oil pressure my rpm's also drop at idle sometimes below 500. would readjusting my idle help?? I know this isnt the post that you were looking for, sorry, just know that you are not alone.

Paul H.

I have a 92 and mine does the opposite, low when at idle, between half and full when cruising.

REDYOTA, go ahead and adjust the idle to 750. It is very easy. You only need a common scewdriver.

Cebby

Another 93 here. My OP is generally around 1/4 to 1/2 when driving. Foot in it makes the pressure rise, idling makes it drop, usually a little below 1/4 line. This is all with the engine and oil warm. Pressure is generally higher in the winter when the oil is cold. This all seams logical to me.

EDIT: I have 118k on the ticker...

95_4X4Runner

My 'runner had ~125K on it before the engine was ruined by a tire shop, and the oil pressure seemed normal, higher when cold, around half at highway speeds, and lower at idle. Now, with the ATK rebuild engine installed, it goes to half when cold, then stays around 1/4 at highway speeds, and is almost nil at idle when warm. I asked the dealer about it, and they said they noticed the same thing, and checked it with a mechanical gauge after they installed the engine, and it checked OK. I have an Autometer OP gauge to install, but need an adapter....

sandcrawler

like cebby, i should note that when i put my foot down, the oil pressure jumps up a good bit. cruising at hiway speed, however, it pretty much sits around the low end mark.

to be fair, i know i have some oil weepage going on. particularly after a long highway drive, i'll get a little oil under the beast. not sure where exactly it's coming from, but it's dripping down off the front differential.

weep or no, the synth oil has been worth it for me, i believe. engine is much more quieter now that it's not gunked up with dino. i think there was a sticky lifter or 2 (?) when i bought it (1 yr + ago) but now that it's on full synth the engine is as quiet as can be.

Robinhood150

I noticed my oil pressure today on the freeway and it was pretty high compared to what you guys are saying. With the engine RPMs around 2700 my pressure was up near the second mark (on the high side). At idle it's pretty low though.

siboby4

What I'm seeing does not seem normal to me, but sounds like some of you guys have the same thing. I've got good oil pressure
until I run into a hot day ( up here in vermont its 50/50 chance)
then my oil presure drops down to the first 1/4 even at hiway speeds. At idle its nil. On regular days ( between 70 and 80 degrees) it behaves a little different, its in the 2nd quarter at speed and still drops at idle. I was thinking that maybe it was time to change out the oil pump, but just wanted some opinions from u guys. Sounds like I'm ok for now. What does worry me is that I don't have a oil light, not sure if its burnt out but when I turn key on I get no oil light !! My old truck (80 4wd ) had an oil light. It also had a oil pressure gauge and the pressure was always high, even at idle.

Thanks again,
Bob

Tofer

My 94's oil pressure is low at idle (1/4 mark) but once i am rolling, it moves up to between 1/2 and 3/4 and stays solid until i am at idle again... at least i am not the only one with this issue (if it is an issue, or is just a toyota thing). makes me feel a little bit more confident.

leebee

my 93 does pretty much the same as most others that have posted. high when cold and settles down at highway speeds and drops to near 1/4 at idle. good thing is, no one has reported an engine failure due to this.

lee

Amkeer

It should be at 4.3 psi minimum idling at normal temps. That relates to below the 1/4 mark. It should 36-75 psi at 3000 rpm.

leseid

Old thread, I know. But I have not found my answer anywhere else and thought it might be an appropriate question here.

Just bought a 92 3 liter and noticed the exact same oil pressure situation as described above. Just curious whether the oil pressure regulator valve could be coming into play here. In my experience, the max oil pressure I see on my gauge drops very fast, compared to the gradual drop I see on other rigs as the engine warms. Just wondering if such a sharp fall could be related to the pressure valve being either erratic or abrupt by nature, or possibly faulty? My understanding is that it is only supposed to throttle down the max pressure and keep it from getting too high and causing turbulence/air entrapment at high rpms. Perhaps it is by nature just too enthusiastic?

eddieleephd

I have to ask what type of oil and what viscosity?
Synth. Dino. 10-20 or 10-30 ?

depending on what the answer depends on what I would suggest to do.

jason191918

I would install a mechanical oil pressure gage before coming to any conclusions to see where you are really at.

leseid

1) it's not a viscosity issue per se. Can't be with so many people, with so many different oils describing the same scenario.

2) I am not interested, personally, in the absolute oil pressure but rather the relative huge range of hot 2-3k rpm cruising oil pressures that I and others see.

3) I doubt anything needs to be done about it anyway, just curious about it why it is.

eddieleephd

x2
Actually from earlier posts I see it to be a viscosity issue.
Simply because This is said to be once warm hence when the oil warms up it is more
viscous and thinner! This is when the oil pressure drops! not when it is thick and
less viscous at cold temps!

First I would do as jason says install a manual oil pressure gauge this will show you
if it is in the danger one what so ever!
Next I am with you it is most likely not a horrific issue!

However If I were worried about this the thing I would try is Lucas Heavy Duty Oil Stabilizer! You know the stuff that is in most auto stores in the thing with gears showing how It thickens the oil to stick to the gears an is thicker on the top gears than
the one next to it!
Well If you put about .5-1 quart in at your next oil change and see what this does for the oil pressure. I think that your pressure would increase noticeably!

The reality being is the reason they mix the viscosity's of oil is for protection at different temps. "cold start=5w or 10w operating temp being 20w to 30w" Well if you add another grade for Hot temps which is when most people are reporting the lowest
pressures I believe that this would alleviate this issue in large part!

I will say that I would start with a half of a quart in my next oil change and see what this does.

Basically It is just a high viscosity gear oil and mixing .5 quart in with 5 quarts is just going to thicken it a little and give you a better protection at higher temps. like when towing, desert running, 4x4ing any time when the engine is working at a higher temp.

really this is just my.02 take it how ever you will.

I am not an automotive expert but do have a little understanding of the physics of the internal combustion engine and Oil.

Ardent

x2 With that big of a range, it's going to be all over the place at different RPMs.

Also, to clear up some confusion, I'm pretty sure that the SR5 cluster has no "low oil light" only the non-SR5 (no tach) gauges did because they don't have the Oil Pressure gauge. To test my theory, just turn the key to the "on" position without starting the truck. I'm pretty sure you'll only see the battery, engine, Brake!, ABS (if equipped) and Rear door (4Runner).

I just did my SR5 cluster swap, and there was no location for the oil light either.

eddieleephd

The air bag light! thats the other one

Glad I have the light!