What is the pressure in the engine oil cooler?

[ganda1f]

I have a slight oil leak from the line to the engine oil cooler. It leaks where a metal line connects to a rubber hose, right next to the oil filter. Roughly a drop forms every 3 miles or so. I examined the hose but I could not find any obvious reason for it to leak.
So I thought that maybe the cooler is clogged (possibly partially) and when pressure builds up the joint starts to leak.
It is just a rubber hose going over a metal line and the hose is held by a clamp, so I doubt it can hold much pressure.

Can anyone tell me how the oil is fed into the cooler? Is it pumped or does it just flow down through the cooler on its own due to inlet and outlet being at different heights? It is a factory mounted cooler, no turbo charger mods or anything.

Do you think this theory about clogged cooler being any good? The car has been well maintained for the past 7 years, regular oil changes, fully synthetic oil. No problems otherwise. I am getting a new hose, but I thought perhaps someone knows more about this problem.

Tried to search but no luck. Mostly threads about aftermarket cooler installs.

[Bitter]

transmission oil cooler? the engine does not have an oil cooler stock that i'm aware of on this generation.

[ganda1f]

Not transmission oil. Engine oil. It is a european vehicle. 4AFE have the oil cooler. Not sure about 1.3l 4EFE.
It has a manual transmission by the way.

[Bitter]

ah thats odd, the cooler is built into the radiator or is external? if its built into the radiator is it on the left side (from inside the car)? if so then they're just using an automatic trans rad with its oil cooler for engine oil.

anyways, i'm not sure what pressure its under honestly. i would assume the same pressure as the oil is at the filter or anywhere else in the pressure system. since the oil pump creates uniform pressure throughout the system.

[ganda1f]

The oil cooler is external. It is located in front of the driver's (left) side lower corner of the AC condenser. And it is roughly 1x0.5 ft in area. Looks just like a miniature radiator. Counting from the front of the car there is the bumper, oil cooler, AC condenser and the radiator.

What is the pressure at the filter? Isn't it around 4-5bar (48-60psi)? A flimsy clamp on a rubber hose wouldn't be able to hold that, would it?

What determines how much oil should go through the cooler? Could there be some kind of thermostat?

There is nothing about the oil cooler in the Haynes manual, so I sort of just throw questions in the air hoping to get lucky

[speedy25]

The pressure in the cooler is the same as your engine oil pressure.

The reason its leaking is because the rubber of the hose is hardening from all the hot oil its carrying. Next it will degrade and pieces of the hose will go tripping through your oiling system.

Change them!

-SP

[trife96]

do you have a pic possibly...I'm in agreeance with Bitter. The 7th gen came with only a tranny cooler that I'm aware. Two nipples on the bottom of the radiator with a hose for in and out. The cooler itself (is hidden in the lower plastic base of the radiator. Are you SURE it's oil???

Oil pressure at idle it should be around 4psi. The O/P sensor is located at the front of the engine near the alternator. You can disconnect the sensor from the engine block and screw in a test guage with the proper fitting and threads.

[Kiwi-Corolla]

Originally Posted by ganda1f

The oil cooler is external. It is located in front of the driver's (left) side lower corner of the AC condenser. And it is roughly 1x0.5 ft in area. Looks just like a miniature radiator. Counting from the front of the car there is the bumper, oil cooler, AC condenser and the radiator.

Interesting, would be keen to see a photo of it if you ever get a chance.

[speedy25]

Originally Posted by trife96

Oil pressure at idle it should be around 4psi.

4 psi?? I'm hoping you forgot a zero on the end of that. If it were 4 psi you need an oil pump BAD.

-SP

[ganda1f]

Thanks for the heads-up on the hose Speedy25. The inner surface of the hose looked more like that of french fries than rubber. I cut the hose open and it would just crack all over as soon as I bent it. Installed new hose and it holds tight.

As for the pressure, I talked to a Toyota mechanic and he said that it is in fact reduced from what the pump supplies. The oil would flow too quickly through the cooler otherwise, since the return line goes directly to the oil pan.

Here are some pics after repair.

This is the connection that was leaking. Right where the yellow dot is on the black rubber hose.


The lines go under the condenser to the bumper on passenger side.


View from the front


The lines turn towards driver's side where the cooler is mounted.


The oil cooler. On the driver's side.

[topnotch]

wow interesting mine dosnt have that.

[Kiwi-Corolla]

Same here, that's pretty cool.

[ganda1f]

Depending on driving habits and the climate the car is run in, the oil cooler may not be necessary. But then again New Zealand is not really known for its blistering cold

[Bitter]

hmm very very interesting. thats a pretty robust cooler too. i need a trans cooler for my celica, something like that would be ideal!

[ganda1f]

Glad to provide inspiration