Thread: Does anyone let their vehicle cool down before a water crossing?

I guess it depends how far / fast you have been travelling before the crossing. A friend of mine owns road trains that service several of the remote communities around the gulf of carpenteria and he makes his trucks stop at any crossings and let things cool down a bit if they have done long distances. I have seen a couple of the front diffs in his yard that have apparently happened from driving into water after many hours of non stop driving.

Cheers Ean

Yes I always do if it's been a long run and the driveline is hot. By the time you stop, check the crossing depth, etc and smell the wildflowers, a lot of cooling can happen. Good practice I reckon and 5 or 10 mins break by a crossing doesnt hurt the human either.

Raised diff and gearbox breathers are important too. And after big crossings at the end of the day I often check my fluids for any sign of milkyness.

I also let tbe engine idle for a minute or two after a long run anytime (not just at water crossings), to let the turbo cool, etc.

Long enough to check for depth and conditions is long enough.

Always done a cool down if a long run beforehand. Good times for a cuppa, and a walk around. If fairly deep, I'll watch a few other cars go through as well.

Originally Posted by donh54

Always done a cool down if a long run beforehand. Good times for a cuppa, and a walk around. If fairly deep, I'll watch a few other cars go through as well.

Haha that's a good idea! It's funny there are so many off road TV shows and youtube clips etc. which all have good stuff in them but not once have I seen someone talk about waiting before a water crossing, even though it's common sense that hot metal doesn't ever like hitting cold water.

Originally Posted by donh54

Always done a cool down if a long run beforehand. Good times for a cuppa, and a walk around. If fairly deep, I'll watch a few other cars go through as well.

Exactly what my dad and my step dad always said, as back in the day breathers were only on the actual items, not extended.

Have a cuppa, and then all our compartments are nicely cooled down.

Originally Posted by Young Angus

Haha that's a good idea! It's funny there are so many off road TV shows and youtube clips etc. which all have good stuff in them but not once have I seen someone talk about waiting before a water crossing, even though it's common sense that hot metal doesn't ever like hitting cold water.

It’s not so much to avoid the hot metal in water as it is about minimising or stopping water getting sucked into diffs or trans. As the temp of the hot diff reduces as it is immersed in water a vacuum is created inside. This is why extended diff breathers are good because they will equalise the pressures without any water being sucked into the diffs or transmission.

Even with good breathers it is good practice to stop it let things cool down.

I always stop and let the driveline and engine cool down

As said before the hot air inside gearbox transfer box and diffs if rapidly cool down, will create a vacuum to suck water in

If you have a defender, it is particularly important because those stupid rubber cap on drive flange will act as diff breather