Radiator Replacement, ATF top up needed?

[rumpfy]

To go from a 0.9 bar cap to a 1.1 bar cap, would raise the water boiling point by about 5 degree C.
At 0.9 bar, the boiling point of water is about 116 degree C.
In an ambient temperature of 70 degree C the temperature difference between the cooling water with a 0.9 bar cap, and ambient is around 46 Deg C, and with the 1.1 bar cap, that temperature difference becomes about 51 degree C.
There is an increased cooling rate of the order of 10%.
It is suggested that the only time one would need a 1.1 bar cap is in the very hottest of conditions at full engine power, otherwise there is no benefit in using the higher pressure cap.
More importantly, the thermostat needs to be operating properly. ie, shut at 80 degrees and fully open by 90 degrees
Hope this helps.

[metzger]

Thanks for the info.

Autobarn have Penrite ATF FS 4L bottles for $39.99, so i got two and will replace my fluid soon.

[metzger]

I changed the fluid today. I had driven the car that arvo then let it sit for an hour and a half before starting the work so fluid had some heat to it.

Put it in neutral and watched about 5L come out, then drained about 1L from the drain plug (which was a 24mm, same size as oil sump plug). The end of the plug had metallic "fur" on it, probably typical for 243,000KM, also some kind of black sludge or grease was around the tip where the "fur" was, so i wiped it all off and put the plug back in.

Then i put 6L in from where the ATF dipstick goes.

I then ran the car in neutral again and made about 2.5L come out. But i put only 2L back in, checked the dipstick and level looked good. I still got 500ML here if the dipstick level changes.

Now when i check the dipstick the fluid appears to be correctly around the HOT marking, before it looked like it was well over HOT.

Took it for a quick test drive, it shifts and drives fine, but feels like there is some more shudder when idling in drive, maybe that will reduce later idk.

The overall condition of the old fluid looked okay, didn't see any metal pieces or debris in it. It had an almost dark red colour to it when it was soaked into a paper towel.

Fluid i used was Penrite ATF Full Synthetic Multi Vehicle 4L x2.