3" spot of leaking coolant...

[jgold47]

also the coolant temp sensor o-ring or is that only for 3.0?

[bbultman]

small spots of coolant by passenger inside/front of wheel is almost surely the aux fan switch o-ring that is in the lower radiator hose just aft of the radiator connection. Mine would only leak after the truck ran for at least 30 minutes. O-ring is not sold separately but the whole switch with o-ring is only about $15. however, swapping it out is a bit more involved. I did mine when I replaced all the cooling system hoses and radiator.

[jgold47]

Originally Posted by bbultman

small spots of coolant by passenger inside/front of wheel is almost surely the aux fan switch o-ring that is in the lower radiator hose just aft of the radiator connection. Mine would only leak after the truck ran for at least 30 minutes. O-ring is not sold separately but the whole switch with o-ring is only about $15. however, swapping it out is a bit more involved. I did mine when I replaced all the cooling system hoses and radiator.

If you go hardcore google, you will find a single thread with an e46 guy who found the correct size for the o-ring. I bought a box at Home Depot for like a buck. 6 months later, no issues. I didnt think it was that hard at all...

[bbultman]

I don't have time to search for the exact fit o-ring to save some spilled coolant and a couple bucks which is literally nothing compared to the thousands of dollars and time I have socked into my 4.6is. Mine has been well taken care of but after 10 years, things just start getting brittle and leak or break. Yesterday I had my passenger window regulator break (driver's already went). If it didn't have a 4.6is Dinan, I would've dumped my X5 long ago. The things that have gone bad on my X5 plagues all X5s - cooling system leaks, valve cover gaskets, window regulators, TC/trans. If these haven't troubled you yet, good luck. Mine was pretty much trouble free for the first year. I thought I got a 'good one' and was in the clear. Ha!