1UZ and suitable engine oil temperature

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melvinmelvin

Member
Messages
263
Location
Bangkok
I am not happy with the oil temperature on my 1UZ:

I have a relatively big Monster radiator with two powerful Bosch thermostat controlled fans.
I am using the red anti freeze fluid in black plastic cans, Toyota pre mixed coolant.
There is between 10 and 11 liters of coolant in the system.
The fans start at about 92/93 degree celsius.
The coolant temp is steady between 90 and 94 degrees celsius.
I am happy with that.

I have fitted a relatively large Monster oil cooler.
The place the cooler is fitted is not great. Its right behind the engine
so the cooler doesn't get much of a natural air flow.
To compensate for low natural air flow I have 5*25Watt fans mounted on the
back of the cooler, (fans running all the time).
There is about 5.5 liters of Toyota fully synthetic 5/40 in the system.

When running at about 2000-2300 rpm the oil temp is below 100 celsius (just).
When increasing rpm to 2500 and a bit above the oil temp goes to 105 and above. I don't like that.

Now, what would you guys say that the oil temp ought to be be?

Am I completely on the wrong track when I expect the oil temp to be close to the coolant temp?
 
Use a laser temp gauge

Borrow or buy a laser temp gauge. First of all check the laser temp gauge is accurate by measuring something you know to be around 100C then test the fittings and heat exchanger (radiator) your using. It should show a noticeable temp drop from in to out and debunk from there.

I am not happy with the oil temperature on my 1UZ:

I have a relatively big Monster radiator with two powerful Bosch thermostat controlled fans.
I am using the red anti freeze fluid in black plastic cans, Toyota pre mixed coolant.
There is between 10 and 11 liters of coolant in the system.
The fans start at about 92/93 degree celsius.
The coolant temp is steady between 90 and 94 degrees celsius.
I am happy with that.

I have fitted a relatively large Monster oil cooler.
The place the cooler is fitted is not great. Its right behind the engine
so the cooler doesn't get much of a natural air flow.
To compensate for low natural air flow I have 5*25Watt fans mounted on the
back of the cooler, (fans running all the time).
There is about 5.5 liters of Toyota fully synthetic 5/40 in the system.

When running at about 2000-2300 rpm the oil temp is below 100 celsius (just).
When increasing rpm to 2500 and a bit above the oil temp goes to 105 and above. I don't like that.

Now, what would you guys say that the oil temp ought to be be?

Am I completely on the wrong track when I expect the oil temp to be close to the coolant temp?
 
Where are you measuring the oil Temp?

By the oil filter.

The oil cooler was supplied with a biggish coupling that is screwed into
the engine (replacing the filter) then the filter is screwed into the coupling.

Temp sensor and pressure sensor is also fitted to this coupling, I'll take
a closer look later today.
 
Borrow or buy a laser temp gauge. First of all check the laser temp gauge is accurate by measuring something you know to be around 100C then test the fittings and heat exchanger (radiator) your using. It should show a noticeable temp drop from in to out and debunk from there.

Wish I knew where to get hold of a laser temp gauge in Bangkok,
but I'll ask around.
 
Where are you measuring the oil Temp?

Have had a closer look.

When mounting the Monster oil cooler the oil filter is taken out,
and the coupling supplied by Monster is screwed into the filters place.
Then the filter is screwed into the Monster supplied coupling.

The pressure sensor is screwed into the Monster supplied coupling.

The temperature sensor is screwed into an original Toyota bracket just inside and slightly above and forward of the oil filter.
 
Before or after the cooler? Is the sensor in the oil flow or could it be measuring the heat soak of the adaptor which may have hot uncooled oil and then the cooled oil flowing through it?

One job we did was a turbo 1uz with an oil temp sensor in the sump. Temp was fine until the engine was held at boost for a period of time. When the oil temp sensor was mounted into the sump it was directly below the oil drain for the turbo so the oil temp was measured extremely hot(115-120C was common). In reality after measuring the oil flowing back to the engine after the oil cooler it was well within acceptable limits and around 40-50 degrees lower.
 
Well, not sure your question is directly applicable.

The oilfilter is screwed into a bracket on the left side of the engine block.
This bracket is not screwed onto the engine block but is an integral part of
the engine block cast.

The temperature sensor is screwed into this bracket.
(the pressure sensor is screwed into the Monster coupling)

To me it looks like the "hole" where the temp sensor is screwed in is the
original place for the temp sensor (or maybe the pressure sensor).
 
I was driving mine today and it sits at around 80-85degrees C.

My sensor is in the standard oil cooler bracket in one of the plugged holes. I don't run a cooler now the supercharged engine is gone.

You need to ascertain if the sensor is in the oil stream flowing to the cooler or the oil stream returning to the engine after going through the cooler.

The correct position is after the cooler.
 
I was driving mine today and it sits at around 80-85degrees C.

My sensor is in the standard oil cooler bracket in one of the plugged holes. I don't run a cooler now the supercharged engine is gone.

You need to ascertain if the sensor is in the oil stream flowing to the cooler or the oil stream returning to the engine after going through the cooler.

The correct position is after the cooler.

Right, I'll have closer looks and see if I can decipher the bracket where
the sensor is screwed in
 
I was driving mine today and it sits at around 80-85degrees C.

My sensor is in the standard oil cooler bracket in one of the plugged holes. I don't run a cooler now the supercharged engine is gone.

You need to ascertain if the sensor is in the oil stream flowing to the cooler or the oil stream returning to the engine after going through the cooler.

The correct position is after the cooler.

Btw,
you say your oil is at 80/85 Celsius,
what is your water/coolant temperature?
 
Around 95degrees C.


thanks, and wow!

oil temp about 10-15 degrees below coolant temp,
that would suit me fine

thanks

will dig deeper into this now, need to sort out a few other things first though,

and see if I can get hold of one of these infrared temp measuring devices
 
had a fairly close look today

(the engine is presently out and sitting in a bench)

cannot really ascertain by just looking if the sensor is in the hot or the cool
oilstream

will get hold of a infrared thermometer and check temperatures when engine goes
back in

I am now reasonably sure that my pre-VVT 1UZ stems from a late 1994 Celsior.
Anybody knows where the original oil temp sensor was scfrewed in?
 
During my recent road trip I kept an eye on water and oil temps due to this Thread.

Water temps never went above 100degreesC no matter how hard I pushed the car. Obviously the standard Range Rover radiator is pretty good.

Oil temps varied between 85 and 125degreesC.

On long hills in third and sitting on 100-110kmh the oil temp rose fairly quickly to 110-115 then slowly got up to 125. I run synthetic oil so the temp doesn't bother me but I thought it worth passing on.

Once I crested the hill and changed up to 4th or 5th the oil temp dropped to 100 or less in a few minutes.
 
During my recent road trip I kept an eye on water and oil temps due to this Thread.

Water temps never went above 100degreesC no matter how hard I pushed the car. Obviously the standard Range Rover radiator is pretty good.

Oil temps varied between 85 and 125degreesC.

On long hills in third and sitting on 100-110kmh the oil temp rose fairly quickly to 110-115 then slowly got up to 125. I run synthetic oil so the temp doesn't bother me but I thought it worth passing on.

Once I crested the hill and changed up to 4th or 5th the oil temp dropped to 100 or less in a few minutes.

right,
thanks a lot for the info

last week I received the infrared thermo I had ordered

wednesday last week the engine was installed again after having
sorted out some propeller rake problems

my plan was to check the temperatures on oilcooler and hoses
and where the hoses are connected to the engine when I got home
from my mechanic

10 minutes after leaving my mechanic the bitch sunk in a very
tricky spot in the river
the day after the boat was raised and the engine hauled
and the folowing day it was in very small pieces

will see how it works out,
may come back to this thread later (next year that is)
if I decide to rebuild the boat or buy a new one
not sure right now what I will do
(the boat was very bady damaged)

this was very very close to a fatal event, I am lucky as hell that
I survived

still want lower oil temps though
 
I hope you had a life jacket.

I assume the boat didn't sink because it sprang a leak, rather it hit something in the water?

Glad you're still with us.
 
I hope you had a life jacket.

I assume the boat didn't sink because it sprang a leak, rather it hit something in the water?

Glad you're still with us.


stupid me didn't have a life jacket, thats why this was very close to fatal,
am not a good swimmer anymore and especially not in river streams

hit something? no

sprang a leak? yes
whole the size of a A4 (20*30 centimeter) sheet in the bottom,
rotten stringers and rotten bottom panels
 
At last, today all wee bits of the engine put together, exhaust manifolds/pipes back on,
gear box back on, temporary cabling of instruments done
and a bit of this and a bit of that

and the mill started! wow, right away

(tried the ECU that sank, it was openes cleaned in fresh water and hairdryer dired,
didn't work at all - just no life)

had an old ECU available, with which the mill runs on 7 cylinders, or 7 pistons as they say in Thailand,
with that ECU the sucker started right away

Not bad.

Now, have to sort out the boat, or probably build a new one.
 
I was driving mine today and it sits at around 80-85degrees C.

My sensor is in the standard oil cooler bracket in one of the plugged holes. I don't run a cooler now the supercharged engine is gone.

You need to ascertain if the sensor is in the oil stream flowing to the cooler or the oil stream returning to the engine after going through the cooler.

The correct position is after the cooler.


right,
Have had a lengthy job fixing up some injectors and some ECU wiring,
the mill is now running fine,
without producing any annoying white exhaust.
Its now put to rest and will sleep until my new boat is finished, about end of April I guess.

Ran the engine for a couple of hours yesterday. Among other things I
measured some temperatures here and there.
It seems that my oil temperature sensor is placed in the hot oil stream
going to the cooler,
rather than in the oil stream coming back from the cooler.

I have 5 small 25 Watt electrical fans mounted on the back of the cooler.
Very difficult to detect any significant temperature difference unless the
fans are running. When the fans are running the difference in temperature is very significant. (between the hot and cool stream that is)

(the oil cooler fans are connected to the same relays as the radiator fans,
they fire up at about 90 centigrades)

So you suggest that I should swap the oil cooler hoses on the flamnge then?
So that the return stream runs past oil temperature sensor.
 


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