Coolant loss - air oil separator (AOS)

[Hilux2400]

I have a coolant leak on my 2003 Carrera 2 which is coming from the area of the AOS. It's not the coolant reservoir, but up at the back somewhere on the left side. I will get it on a ramp this morning.

Has anyone experienced splits in the AOS coolant exchanger that have resulted in coolant leaks?

I am hoping that it's just a clip that needs tightening, but I think the AOS might have to be replaced.

Thanks for reading.

H

[Rockster]

Hilux2400 said:

I have a coolant leak on my 2003 Carrera 2 which is coming from the area of the AOS. It's not the coolant reservoir, but up at the back somewhere on the left side. I will get it on a ramp this morning.

Has anyone experienced splits in the AOS coolant exchanger that have resulted in coolant leaks?

I am hoping that it's just a clip that needs tightening, but I think the AOS might have to be replaced.

Thanks for reading.

H

No direct experience with the 996 AOS but I've read plenty of posts from those that have had this go bad and one sign is a coolant leak. (I've gone through 3 AOS's with my Boxster but the AOS in the Boxster is "dry". No coolant.)

You can check if it just a loose clip or clamp or a hose leaking but I suspect you'll find the AOS is bad.

[Hilux2400]

Thanks for your reply. I think we have found the problem. It's on the return vent line to the header tank. This a narrow metal pipe, about 18mm diameter, that runs upwards near the AOS. It has been chafing on a pipe clip near the block. At both ends there is a short hose connection that I can clamp off. Having done this I might be able to thread the new pipe through without losing too much coolant.

I will probably have to remove the air filter and air pump to get some space, but I hope this will be the full extent of a clearance to get the job done.

H