Oil Pressure

[goatfarmer]

1990 T4r, automatic, with 204K: currently running 10x30 and oil pressure runs in the normal range; however, once the engine temp is in the normal range and the vehicle is running at idle the oil pressure drops close to the 0 mark but once the vehicle is rolling the oil pressure moves back into the normal range. I do not see this ole timer rebuilding, or replacing the engine, been there, done that on a few occasions, considering giving it away to a relative for a later model but do not want to pass on a lemon!

Suggestions/Comments appreciated!!.

 

[Bad_Vision]

A quick search would reveal that this is a common problem with the Toyota old engines.
The gauge is a very old system and they don't need the pressure of newer engines because the tolerance is really big on older engines. Switch to 5/30 and see if that makes a difference if your still worried about it. I put a 1/4 quart of atf in my engines to clean them out been doing it for 130,000 miles on my 3.4L and oil is clean as new at 5,000 miles on conventional.


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[goatfarmer]

Thank you for the quick response. Last oil and filter change was probly a 2-3 k miles ago but will change both within the next few days and see if any improvement. Again I thank you!!.

 

[wallytoo]

i wouldn't count on 5w-30 making any difference in your oil pressure, compared to the 10w-30 you are using now.

try 20w-50 or 15w-40. even so, any change is going to be a bandaid to whatever is not right in your engine (ie, rod bearings worn out with excessive clearance).

 

[flyinhawaiian01]

I too don't believe there's anything wrong with the way that engine is running. Its simply an older system that fluctuates more than newer vehicles.

I would agree that you will not see any change going from a 10W-30 to a 5w-30, as the "W" stands for winter. Unless you're starting it up in temps below 32ºF right now, the winter number doesn't play much of a part in the viscosity of the oil.

I would try running the 15W-40, or really, at this point in time, just go to a straght weight oil. 40 weight would allow you to see whether the pressure comes up a bit, it will also create a thicker barrier on metal surfaces for added protection.

As a reference, my truck has always shown, when fully warmed up, almost no pressure on the stock gauge at idle, and will run up to just below the halfway mark on the gauge at anything over 1600rpm or so. I also run either Royal Purple 10W-30 or Mobil1 10W-30 in it, its always seen quality oil and I've not had any oiling issues with the above pressure.

 

[goatfarmer]

i wouldn't count on 5w-30 making any difference in your oil pressure, compared to the 10w-30 you are using now.

try 20w-50 or 15w-40. even so, any change is going to be a bandaid to whatever is not right in your engine (ie, rod bearings worn out with excessive clearance).

Since I do not put more than 3-4 K miles per year I will probably try going with the heavier grade oil and see if there's any noticeable improvement. I do not believe it would be worth having the engine repaired, with that many miles I would imagine something else will surface not far down the road. As a last resort, and since I will need the space, if I should decide to replace I may consider donating it to a public run agency and see what I could write off for tax donation purposes??

Appreciate the input!!!

 

[flyinhawaiian01]

Personally, I wouldn't go any more than 40 weight on an old engine. It will help to reduce the clatter of an older engine, but it also puts a bit more stress on other things too, most notably the oil rings. If you start noticing a bit more smoke out of the tailpipe, I'd get it changed back to 30 weight immediately.

 

[Wazukie]

Put a real pressure gauge in and verify what it really is. Your pressure will always drop as the oil warms up. viscosity always goes down as heat increases. The stock gauge in the 4runner sucks.

 

[goatfarmer]

Never used synthetic oil and not sure it would be advisable at this point. Probably go with standard 30 or 40 wt., perhaps experiment trying non-detergent?

I may have a spare oil pressure gauge for comparison, but noticed the pressure dropping, especially over the several months, more recently been creeping toward zero at idle; somewhat encouraging pressure moves to normal range when rolling. Intend watching for any improvement with the heavier wt. oil?

Again, appreciate the input!!

 

[wallytoo]

i wouldn't use non-detergent oil in any engine from the 50s onward. a 30 rated non-multigrade won't be appreciably different than the 10w-30.

a 40 or 50 viscosity rated oil should be fine.

 

[4runninky]

i have a 95 and it seems to b normal for these engines after a lot of research. i read somewhere that normal operating temp oil press at idle it like 4-5psi. lol

 

[4runninky]

another thing i have also read is that these engine don not like the higher vis oil. some complained of having oil leaks when they used it and the oil leak went away after changing back to 10w30. just what i've read.

 

[goatfarmer]

Admittedly have not monitor the oil pressure to any extent until recently when I noticed the oil pressure hovering around 5 psi at idle? Tomorrow, or next, intend changing to non-multi grade 30 weight oil and monitor closely.

Can not thank U's all enough for the input!!

 

[goatfarmer]

Update: This a.m. purchased the oil and filter and explained why I was going from 'multi-grade' to 30w, the counter person suggested I try an 'oil stabilizing' additive, he recommended adding to existing 10-30w, but I thought it best to change both filter and oil, perhaps 4 qts. 30w to 1 qt. of oil stabilizer?

It appears the product has favorable reviews and thought I would check if member(s) tried the product and have an opinion??

 

[flyinhawaiian01]

I dunno, I'm not a fan of putting any additives into a vehicle at all, aside from maybe a can of motor flush or atf if I feel the engine really, REALLY needs to be cleaned out (pretty much any old vehicle I buy used and have no clue how it was taken care of), and that comes right back out 5-10 minutes after putting it in.

I think you're worrying about an issue that's not really there. Most all of us with the same engine and same oil pressure all noted the same readings, yet none of us have had any damaged engines due to low oil pressure. Run the 30 weight, non-synthetic oil, change the filter, change it in 3,000 miles or so and keep an eye on the gauge for the next few months, remembering that it really is perfectly normal readings.

Thought I'd also add that most counterpeople, especially at Autozones and other bigbox parts stores, are "encouraged" to upsell customers with that kinda crap, some places will actually pay the store and/or the employee "spiffs" for selling stuff like that. Usually its all the crap they have right up front by the registers, but not always.

You seem to be a bit hesitant to say what the stuff is, so I gotta ask, what did he sell you to add to the oil? And please don't say slick50!!!!

 

[goatfarmer]

I dunno, I'm not a fan of putting any additives into a vehicle at all, aside from maybe a can of motor flush or atf if I feel the engine really, REALLY needs to be cleaned out (pretty much any old vehicle I buy used and have no clue how it was taken care of), and that comes right back out 5-10 minutes after putting it in.

I think you're worrying about an issue that's not really there. Most all of us with the same engine and same oil pressure all noted the same readings, yet none of us have had any damaged engines due to low oil pressure. Run the 30 weight, non-synthetic oil, change the filter, change it in 3,000 miles or so and keep an eye on the gauge for the next few months, remembering that it really is perfectly normal readings.

Thought I'd also add that most counterpeople, especially at Autozones and other bigbox parts stores, are "encouraged" to upsell customers with that kinda crap, some places will actually pay the store and/or the employee "spiffs" for selling stuff like that. Usually its all the crap they have right up front by the registers, but not always.

You seem to be a bit hesitant to say what the stuff is, so I gotta ask, what did he sell you to add to the oil? And please don't say slick50!!!!

Thank you for the input; agree, never have added an oil additive to the vehicle since driving off the lot new. Going with the 30 and monitor.

 

[Wazukie]

I now that with my 93 3.slo(Just put a new motor in) the factory system doesn't read the true pressure. I had the same concern, since I was putting new engine in, so I put an external, Manuel, old school, gauge in and everything looks good. I use the factory setup to gauge "normal" for my rig.

 

[goatfarmer]

I now that with my 93 3.slo(Just put a new motor in) the factory system doesn't read the true pressure. I had the same concern, since I was putting new engine in, so I put an external, Manuel, old school, gauge in and everything looks good. I use the factory setup to gauge "normal" for my rig.

Appreciate the information: current plan is to change oil and filter, then monitor for couple K miles before taking the vehicle to local shop and have a basic health check done. A couple engine issues came up a few weeks ago so I arranged to have the local shop check it out; meantime, made a couple adjustments, stars must have come into alignment, except for low oil pressure issue, the vehicle is currently running okay?

Again, thanks to 'all' for the suggestions, it has been extremely helpful!

 

[flyinhawaiian01]

I'd like your posts, but someone stole the LIKE button!!!

Where'd it go?

Am I going :crazy: ?

Keep us posted on your findings, it would be good info for the group to know, I'm sure this question will come up again!

 

[goatfarmer]

I'd like your posts, but someone stole the LIKE button!!!

Where'd it go?

Am I going :crazy: ?

Keep us posted on your findings, it would be good info for the group to know, I'm sure this question will come up again!

Appreciate your kind comment. Still in my infancy stage of submitting post so I do not have a clue. Did notice there's what appears to be a 'heart' (?) in the ID portion of the member's thread, I have used it in posting favorable comments regarding a member's post/thread??