Strange Liquid Leak On 04 Rx300, Coolant But Not Near Rad...

[pimpin gimp]

Afternoon all,

I've got a leak on my RX300 cooling system, I put around 2l of water into the radiater on a monthly/1000mile basis, yet have never been able to trace the leak. Now I have noticed a pooling of liquid under the car, it's virtuallly central (possibly slightly to the offside) and slightly behind the front wheels. I'm sure that this is coolant as it's definitely not oil.

Any idea what might be leaking way back there?

First thought are that its dripping from elsewhere, and running along the undertray of the car, but with all the holes in the thing I find it unlikely that it would get all that way.

One night this week I'll take the tray off and drive it around for a bit to warm it up and see if i can ascertain the specific leak position, but until then, is there actually anything back there that may be leaking?

No obvious sign of it leaking into the car, but I won't ignore the possibilty of a heater matrix leak...

[Duncan Roberts]

Afternoon all,

I've got a leak on my RX300 cooling system, I put around 2l of water into the radiater on a monthly/1000mile basis, yet have never been able to trace the leak. Now I have noticed a pooling of liquid under the car, it's virtuallly central (possibly slightly to the offside) and slightly behind the front wheels. I'm sure that this is coolant as it's definitely not oil.

Any idea what might be leaking way back there?

First thought are that its dripping from elsewhere, and running along the undertray of the car, but with all the holes in the thing I find it unlikely that it would get all that way.

One night this week I'll take the tray off and drive it around for a bit to warm it up and see if i can ascertain the specific leak position, but until then, is there actually anything back there that may be leaking?

No obvious sign of it leaking into the car, but I won't ignore the possibilty of a heater matrix leak...

Air conditioning system I would suspect, many cars do it. Ignore, it is not deleterious and cannot be prevented.

[pimpin gimp]

Thanks Duncan. I'd suspect you might be right because I didn't use the air-con on the way home tonight and there was no dripping when I got home. But would the air-con be using the coolant? Seems strange.

[ColinBarber]

the liquid (water) under the car is from the aircon.

I hope you are not putting water into the coolant? You really should only be putting in Toyota coolant. How much does the coolant drop in the expansion bottle? My old RX300 used to expel most of the coolant, it was always at the minimum mark but never went below. If I filled it up, it would drop down back to the minimum mark.

Check around the water pump and radiator for signs of a leak.

[pimpin gimp]

Ah, yeah, I have been using water... It just seemed to be using a lot so I stopped using coolant. It was difficult to see the level of the coolant because of the aged colour of the expansion bottle. The top hose to the radiator is definitely free from fluid occasionally and I use that to burp the air out when I top it up. Then when I top it up I use an old bottle as a hopper, but obviously the expansion bottle fills at the same time. Not ideal but it's kept me running!

I'm tempted to get a Load of the right coolant now and fill it up again, presume the colour (rather than clear) will allow me to see the level?

[pimpin gimp]

Air-con seems even more certain now, yet another 20 mile drive with no evidence of dripping when I stop, because the air-con was off.

Am I OK to assume there is nothing to worry about at the moment then?

I'll go and buy some coolant at lunch time to get some redness back into the system so I can identify the level on the expansion tank.

Cheers all.

[ColinBarber]

using the red/pink coolant makes it easier to spot where is it leaking :)

The amount it is using isn't normal, worth trying to track down where the problem is.