Low oil pressure problem.

Gents since having my supra back I have ran in the new engine without any issues for several thousand miles.

During a recent mapping session we discovered a short on my boost solenoid during the procees of fixing, the electric radiator fans wire to ECU was cut off, the tuner noticed and we corrected the problem including the boost solenoid issue and i finally had boost 'running .8 bar'.

On my way home 10 min drive the electric fan wire came apart and when I got home the car over heated and I lost .5 liter of coolant.

I waited to cool off, corrected the electric fan issue and went for a test drive.

During the test drive I had the toucan peep when I was at 4K rpm oil pressure will not increase past 4 bar even at higher rpm.

Now before my oil pressure when car was on temp was 2 bar and now I am getting 1.4 bar

My oil level is fine, I have no leaks and when emptied oil through filter it came out clean I even past e magnet and found no issues.

Have any of you guys had low oil pressure problems after car over heating?

What next? First check the oil pump relive valve or by pass the oil filter relocation and cooler and put filter as oem? But how could over heating caused a problem with a HKS oil cooler kit 'thermostat' to cause lower oil pressure?

Here is a video of the condition of the oil relief valve.

It came out easy with a magnet it was not stuck as we hopped it was.

Here is a video of the condition it was found when pulled.

Sorry to hear your having trouble.

I guess we can assume that your many thousands of miles running in, would have got the engine hot enough to open the thermostat for the cooler?

If not and you have only just started leaning on it, could it be the first time the cooler has become operative.

I only suggest this as if it's never had oil in it, then when its filled would this have given a pressure drop?

I'm assuming you didn't add any more oil to the system, so would expect the oil level to have dropped a little.

If it were me, I would put the oil side of things back to stock.

Do a pressure check on cranking, then cold, and running, and see what you get.

I wouldn't have thought a minor overheat would effect the oil pressure, especially not in a negative way ie. Less pressure when running.

Seems never ending

Nb. I assume you haven't also got really long oil lines to the relocation, which will also cause a negative impact on the pressure of the system (once it's in full operation, thermostat fully open).

Sorry to hear your having trouble.

 

I guess we can assume that your many thousands of miles running in, would have got the engine hot enough to open the thermostat for the cooler?

 

If not and you have only just started leaning on it, could it be the first time the cooler has become operative.

 

I only suggest this as if it's never had oil in it, then when its filled would this have given a pressure drop?

 

I'm assuming you didn't add any more oil to the system, so would expect the oil level to have dropped a little.

 

If it were me, I would put the oil side of things back to stock.

 

Do a pressure check on cranking, then cold, and running, and see what you get.

 

I wouldn't have thought a minor overheat would effect the oil pressure, especially not in a negative way ie. Less pressure when running.

 

Seems never ending

 

Nb. I assume you haven't also got really long oil lines to the relocation, which will also cause a negative impact on the pressure of the system (once it's in full operation, thermostat fully open).

The oil level has not changed after the over heating, and yes I believe oil always passed by cooler and it only opens further when it gets hot.

The deal is that before the over heating I was getting higher oil pressure and now after 4K rpm the oil pressure will not build past 4 bar as before would see 6 bar plus at wot

I am being really cautious as of now oil comes out clean and I am not scoring or ruining anything else.

Sure its not the oil pressure gauge or sensor?

Sorry to hear your having trouble.

 

I guess we can assume that your many thousands of miles running in, would have got the engine hot enough to open the thermostat for the cooler?

 

If not and you have only just started leaning on it, could it be the first time the cooler has become operative.

 

I only suggest this as if it's never had oil in it, then when its filled would this have given a pressure drop?

 

I'm assuming you didn't add any more oil to the system, so would expect the oil level to have dropped a little.

 

If it were me, I would put the oil side of things back to stock.

 

Do a pressure check on cranking, then cold, and running, and see what you get.

 

I wouldn't have thought a minor overheat would effect the oil pressure, especially not in a negative way ie. Less pressure when running.

 

Seems never ending

 

Nb. I assume you haven't also got really long oil lines to the relocation, which will also cause a negative impact on the pressure of the system (once it's in full operation, thermostat fully open).

Spoken to Chris Wilson he suggested with a piece of wood with tape fit the oil pump valve and work it in and out the plug, clean it really well put it all together again. Remove the oil relocation kit and fit the filter direct on motor and start it again and hope to see a difference. He believes it's not likely the oil filter relocation kit has anything to do with it but it's worth a try testing it like this before thinking of pulling engine out and investigating it further.

Sure its not the oil pressure gauge or sensor?

After my last engine issues I had another separate oil pressure gauge not linked in to Syvecs and they both read the same.

I suppose it's just possible that the oil cooler thermostat has stuck open and now the oil is flowing though the cooler all the time, and you are seeing a pressure drop. Bypassing it with the filter only fitted as per stock will prove or disprove this. Get rid of those bloody electric fans Luiz, the stock one shifts more air and is extremely reliable...

I suppose it's just possible that the oil cooler thermostat has stuck open and now the oil is flowing though the cooler all the time, and you are seeing a pressure drop. Bypassing it with the filter only fitted as per stock will prove or disprove this. Get rid of those bloody electric fans Luiz, the stock one shifts more air and is extremely reliable...

Sad news none of my efforts made a difference the oil pressure problem still remains if anything it's getting worst on hot idle the oil pressure is 1.2 bar and on high rpm does not go over 4 bar.

This is after cleaning the oil pump valve and placing the new oil filter directly on the engine block by passing the oil cooler.

Time to through in the fowl I believe, am bored of it!

Have you double checked your results with an actual mechanical pressure gauge, rather than what syvec sensor is telling you?

Have you double checked your results with an actual mechanical pressure gauge, rather than what syvec sensor is telling you?

I have 2 oil pressure gauges with their own sensors and they match.

Isn't the oil pressures from the Toyota manual as follows: -

Idle, 7.1PSI (0.49 BAR) or more.

At 4,000 rpm, 47-84 PSI (3.241 - 5.792 BAR).

How far outside of those limits are your readings?

What oil viscosity are you running?

As I am sure your aware.

A thin viscosity will give a lower oil pressure reading in the summer months, and now you have been seeing proper boost after running in the hotter the engine oil will be giving a lower reading.

Well I for one certainly hope this isn't the end, you have overcome all your problems to date.

My fingers are crossed for you.

Isn't the oil pressures from the Toyota manual as follows: -

 

Idle, 7.1PSI (0.49 BAR) or more.

 

At 4,000 rpm, 47-84 PSI (3.241 - 5.792 BAR).

 

How far outside of those limits are your readings?

 

What oil viscosity are you running?

 

As I am sure your aware.

 

A thin viscosity will give a lower oil pressure reading in the summer months, and now you have been seeing proper boost after running in the hotter the engine oil will be giving a lower reading.

 

Well I for one certainly hope this isn't the end, you have overcome all your problems to date.

 

My fingers are crossed for you.

The issue is that prior to the over heating and hitting boost I had higher oil pressure using the same oil, I since changed oil to the same nano drive 10 - 50w and I have less oil pressure and am not able to increase oil pressure past 4 bar at 4rpm even revving higher to 7k rpm. Before I would see 6 bar from 4K rpm and higher.

I am dubious and since the oil is coming out clean at least I know I have not trashed the engine with metal particles circulating through oil system.

Could this issue be caused by the turbo bearings at all, when I re conditioned the turbo we did not change the bearings?

I am not a turbo expert but I would guess wear on a journal (NONE ball bearing) turbo could drop oil pressure far more than wear on a ball bearing turbo. Ball bearings are usually either OK or rough and noisy / totally failed. I have doubts the turbo is the lower oil pressure issue though.

Try using a heavier weighted oil. Have you got a oil cooler? High temp out side and high engine temp would.make the oil more have more viscosity and would cause less oil pressure?

The issue is that prior to the over heating and hitting boost I had higher oil pressure using the same oil, I since changed oil to the same nano drive 10 - 50w and I have less oil pressure and am not able to increase oil pressure past 4 bar at 4rpm even revving higher to 7k rpm. Before I would see 6 bar from 4K rpm and higher.

 

I am dubious and since the oil is coming out clean at least I know I have not trashed the engine with metal particles circulating through oil system.

 

Could this issue be caused by the turbo bearings at all, when I re conditioned the turbo we did not change the bearings?

Yes, I see your conern having noticed a 6 BAR to 4 BAR max situation, with effectively having made no changes apart from minor overheat.

Stumped then really.

10w to 50w is a thin oil though, and the hotter it gets 'now your on boost' where you weren't before, will see a pressure drop (amount I wouldn't even hazard a guess at), and a warm climate in Portugal will only make it worse.

Nether the less though it is a condition change, but granted you say it was higher before.

As Chris has suggested it could make a difference if it's failed, but you would be seeing loads of blue smoke 'i would have thought' with the oil being burnt off.

So I agree with Chris, be surprised if it's that unless your seeing something to make you think it is.

Do you have an oil breather set up? and how clean is it if you have one.

Assume all the joints, caps and everything related to that is all tight and secure.

Granted though your probably taking a oil pressure reading from a gallery location, just after the pump has done it's work.

I'm out of any other suggestions

You basically have 2 choices. Cross your fingers and call it "one of those things" and get the mapper to carry on. Or pull the engine and strip it, with particular attention to crank bearing clearances and condition, and oil pump internal condition. I can't see the cam bearing bores causing this, but having said it they were not that great to start off with....

I too am out of none off the wall ideas.

I'd be surprised if it was the turbo as, isn't the oil pressure reduced via banjo bolts to prevent oil seals from being popped? The reason I ask is because this used to be the case, but I'm not sure if it has changed.

Ball bearing turbos need a restricted oil supply.

https://www.turbobygarrett.com/turbobygarrett/turbo_tech_basic

Also click on "Turbo Tech" button for more advanced info and FAQ's

I am not a turbo expert but I would guess wear on a journal (NONE ball bearing) turbo could drop oil pressure far more than wear on a ball bearing turbo. Ball bearings are usually either OK or rough and noisy / totally failed. I have doubts the turbo is the lower oil pressure issue though.

Wouldn't that result in oil smoke from the exhaust though? And probably filling the catch tank?

Not sure it necessarily would, if it's got excessive bearing clearance but good seals the excess flow will just drain down back to the sump. Still can't see a -4 hose and a small restrictor hole passing enough oil to drop pressure much even if it wasn't connected to the turbo at all and just draining back to the sump.

My gut tells me its not right for me to wing it and drive the car as is, something has obviously changed after the over heating issue with the oil pressure and the tendancy is that will get worst and eventually wreck a bunch of expensive parts and machine shop the engine has had.

Some of you know I work in Oil industry and things now are in the dumps, I am unemployed so right now the idea of spending even an extra euro on it its just stupid.

I should be smart and send the car to the UK and have it broken for parts and move on. I am finding it hard though because I have worked so hard to get it right 'hate to give up' but its stupid to carry on like this!

Lee P. mentioned that I could drive it like is and have syvecs trip if it gets any lower and to change the oil to 10-60 w after putting in some miles he also mentioned the idea to drop the subframe and remove oil pump for inspection.

Oil Pressure Facts -

Before overheating and first time putting boost at 1.2 bar than back down to .8bar the on temp steady pressure was 2 bar now 1.2 bar

Before over heating and on boost at 4k rpm and increasing all the way to 7k rpm pressure would increase past 4 bar, I can't be sure but max pressure was for sure above 6 bar.

now the max is 4 bar reached at 4k rpm and will not build past it.

1- Oil is clean no metal particles found

2- Oil pump pressure relief valve is fine and is able to move freely

3- oil has been replaced 'nano drive 10 - 50w with new oil filter and oil filter relocation kit removed and filter back to oem location

4- both oil pressure sensors read the same drop in pressure before and after the over heating issue - awaiting to confirm location of both sensors - they were not on oil sandwich plate.

5- when engine was rebuilt new oil squirters were fitted as with new oil pump and cooler.

I find it odd the oil pressure used to keep on going up until 7K RPM. I would have expected the relief valve to have opened before then and it stabilised before those sorts of RPM. i wonder if the valve wasn't OPENING freely, and now it is? Lee's idea seems fairly safe if you keep an eagle eye on things. The new pressure readings don't sound dire to me.... But it's your car

Hi mate, if you want to use a stock fan I have all the bits and I'm looking for an Srd twin fan kit, you can't give up now you will always be kicking yourself if you do.

Abit late now but having not replaced the squirters and blocked them off would have given you better pressure. The squirters are not needed.