Hello, I noticed that the oil pressure gauge on my '96 was all the way at the top mark while driving and barely came down at idle. We installed a pressure gauge and it read 60psi at idle and close to 100 psi at 3000 rpm! We replaced the oil pressure relief valve and spring. That helped some but it is still varying between 15- 30 psi at idle and around 75-78 psi at 3000 rpm. The dash gauge is still at the top mark while driving. Could the oil pump housing bore be scored in the area where the relief valve sits (causing the relief valve to stick)? I have been told that replacing the oil pump requires pulling the head and half the engine apart to replace. Any ideas what to try next? Thanks.
high oil pressure
- Thread starter TNFJ40
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Bad sending unit, blocked passage i.e. clogged filter
Are you running straight weight oil? Ie 30 weight.
I have the same problem with my 1FZ-FE. Oil pressure looks normal at idle but guage pressure shoots up to the top of the scale at 3000rpm. When I bought the 80 2nd hand, the oil was very black almost like it had never been changed, and there is a lot of black deposit on the oil filler neck under the cap, the inside of the engine must be coated in it.
It otherwise has not needed an oil top up in 3000km, idles smoothly and doesn't sound oil starved anywhere, no knocking or tapping noises. I tried engine flush 3 times already thinking a bit of junk might have blocked a passage, got a lot of thick black oil out each time, but still no difference.
My oil light comes on for about 2 minutes, about 1 minute after starting the engine, and then stays on until the engine is warmed up, the whole time the oil pressure guage registers right at the top of the guage. When warmed up the pressure seems to drop just below the maximum mark when driving at 2500rpm. At idle the guage is between the 2 middle guage marks.
Found this post to be most informative: -
"On the front USDS of the motor there is an extension of the timing cover near the crank pulley, inside this extension is the oil pump, on the back of the extension the power steering pump,
Looking from the bottom of the truck on the far USDS of the extension is a very large hex head it faces partially to the USDS and partially down, remove the hex head and some oil (less than 1 qt) then a spring and then the plunger will come out, you may need a pick or your pinky finger to get the plunger out (note orientation of plunger) put in the new plunger, then new spring, and then old hex bolt with new seal, torque to 36 ft pounds."
But what does USDS stand for?
I'd like to try and change my OPRV too, or at least give them a good clean out if the black tar stuff is clogging up the relief valve system preventing the valve from opening. Is there any risk of engine or oil pump damage if the relief valve stays stuck shut?
It otherwise has not needed an oil top up in 3000km, idles smoothly and doesn't sound oil starved anywhere, no knocking or tapping noises. I tried engine flush 3 times already thinking a bit of junk might have blocked a passage, got a lot of thick black oil out each time, but still no difference.
My oil light comes on for about 2 minutes, about 1 minute after starting the engine, and then stays on until the engine is warmed up, the whole time the oil pressure guage registers right at the top of the guage. When warmed up the pressure seems to drop just below the maximum mark when driving at 2500rpm. At idle the guage is between the 2 middle guage marks.
Found this post to be most informative: -
"On the front USDS of the motor there is an extension of the timing cover near the crank pulley, inside this extension is the oil pump, on the back of the extension the power steering pump,
Looking from the bottom of the truck on the far USDS of the extension is a very large hex head it faces partially to the USDS and partially down, remove the hex head and some oil (less than 1 qt) then a spring and then the plunger will come out, you may need a pick or your pinky finger to get the plunger out (note orientation of plunger) put in the new plunger, then new spring, and then old hex bolt with new seal, torque to 36 ft pounds."
But what does USDS stand for?
I'd like to try and change my OPRV too, or at least give them a good clean out if the black tar stuff is clogging up the relief valve system preventing the valve from opening. Is there any risk of engine or oil pump damage if the relief valve stays stuck shut?
Last edited:
powderpig
SILVER Star
USDS United States Driver side, Must have a book meant for the states.
Anyhow there is another relief valve and spring in the oil cooler. Have you inspect that. Your pressure reading at 3000 is OK, a variing oil pressure at idle is interesing. Like one of the reilefs are creating a problem.
Did you have some sludgeing or any other build up in the engine? If so, maybe use a product to clean the engine out some(one come to mind Auto RX).
Before I would remove the housing, you can change the oil pump O ring and front crank seal. Look at the housing it self and the rotating bits to see if you have a problem in the pump it self.
Again I would look to the reliefs as the low pressure is varing a bit. With the reliefs out and a good flash light and mirror, you may be able to look up inside to see if the bore where the relief valve rides, is in good shape.
Anyhow there is another relief valve and spring in the oil cooler. Have you inspect that. Your pressure reading at 3000 is OK, a variing oil pressure at idle is interesing. Like one of the reilefs are creating a problem.
Did you have some sludgeing or any other build up in the engine? If so, maybe use a product to clean the engine out some(one come to mind Auto RX).
Before I would remove the housing, you can change the oil pump O ring and front crank seal. Look at the housing it self and the rotating bits to see if you have a problem in the pump it self.
Again I would look to the reliefs as the low pressure is varing a bit. With the reliefs out and a good flash light and mirror, you may be able to look up inside to see if the bore where the relief valve rides, is in good shape.
Very useful picture, thank you. How much oil can I expect to come out when I open it up?
I have not opened mine yet and now glad I have not. The dealer could not even find this in his book so I had to get a part number. I did not know what is inside so it looks like I will be replacing my valve and spring because my oil pressure is always been high since I bought it.
and that part number be?
powderpig
SILVER Star
the pic that AZtony show is not the pressure relief valve. It is up higher and has a big nut on it, is in the timing cover to the right of the oil pump cover. I do not remember the size, but is like a 28mm.
that allen head one is in the oil pan and not a pressure relief.
that allen head one is in the oil pan and not a pressure relief.
powderpig
SILVER Star
You also have one pressure relief in the oil cooler. Have you pulled this one as well and see if it is sticking.
If not, do this.
If not, do this.
Mine reads the same as yours, huh?
27mm, deep will not fit....replaced mine this week.
Hello guys,
I'm new to this thread and I jus starter to have the same problem with high oil pressure. Have any of you resolve this problem alrady? I just remake the entire motor few months ago and until now I have this problem. Can any one let me know how or where to start solving this problem.
Thanks
I'm new to this thread and I jus starter to have the same problem with high oil pressure. Have any of you resolve this problem alrady? I just remake the entire motor few months ago and until now I have this problem. Can any one let me know how or where to start solving this problem.
Thanks
I know I'm digging up an old thread but I'm now having the same issue. Super high oil pressure all the time. It was a little high when I bought it last year but it has gotten worse recently. Any solutions to high oil pressure? Any part number for the Oil pressure release valve? Pics of it's location?
I guess I should also give more info. My oil pressure at start up is pegged all the way to the high. Once warmed up it sits just a hair below the 3/4 mark and will immediately peg as soon as I give it gas. I found a couple threads that said it could be clogged filter. New filter and thinner oil (went back to the 5w30) but no real difference. Maybe a tiny decrease. I have heard that I should replace both Oil Pressure release valves but can't find them nor can I find the parts. Not really sure what to do next. The oil pressure sending unit has already been replaced so we can also rule that out.
