coolant leaking...
 

I noticed a nice little puddle under the X5 in the garage yesterday. I was hoping it might be washer fluid since I had just added some. There was another smaller pool under there this morning. Looks more like coolant to me :( It's from just left of center and about 1 foot from the front bumper. Seems likely from the water pump or thermostat - doesn't seem to be from the radiator area. Can't see anything from up top - all looks dry.

I guess this is my que to install the complete cooling system overhaul that I was planning and parts I purchased back in December. This weekend I guess - no time like the present, eh?

At least it got me to skiing and back last weekend without any issues! Might have been lucky there!

I'll be replacing water pump, thermostat, all front hoses and radiator. Expansion tank was already replaced. Valley gasket already failed and replaced about 45K miles ago, so hopefully that is still in-tact.

Nope that valley pan is sure to be the problem again!;) I'm just kidding. Seems like you have everything in order. And as for time, you are right, whether you do it now or next year, you;re still doin' it. Have fun with it!

Oh and another thing, your 4.6, now is that engine the same as the 4.4 just a bigger bore? I was trying to find out the differences between the 4.4 engine and 4.6/4.8.

That and what the difference was between the m62 and N62. I am getting an itch to get a 4.8is, but wanted to know if the engines were the same, just a bigger displacement. If you have any thoughts, let me know.

Thanks.

120K miles it is high time. I was planning to do it in December but ran out of time and decided to go on a 2K mile road trip to OR and then skiing in CA.

4.6 is built by Alpina based on the 4.4i M62 engine, so yes it has more bore or stroke or both, plus different cam tuning and a different vanos set-up too I believe. All told it is good for another 50hp.

4.8is motor may be built by BMW - not sure about those, other than the motor is slightly bigger, they get slightly better mpg and make another 10hp over a 4.6is.

When the valleypan gasket leaks you'll see the pudle close to where the engine meets the bell housing of trans (the V8 is tilted back a bit and there are two draining holes in the back of V8, you'll see these two holes when you lift the intake manifold out).

One thing to make sure, don't overfill the exp-tank just under fill by a tad(pay antention at where the floater suppose to be). This V8 cooling system is presurized thus when the coolant expand it has to go somewhere in the form of small leaks here and there.

It's not dripping back there for sure. Right about where the front of the block is, so I expect either water pump or thermostat or one of the hoses going to those. I guess I'll figure it out when I tear it all apart to replace all that stuff/.

Ahh thanks C4, that i did not know the 4.6 was an Alpina motor. I'm getting the itch baby. LeMans Blue with Ebony interior *drool* Slap some staggered 20's on that sum biotch and probably a valley pan gasket and I am good to go. Then probably get a set of 18's and throw some snow shoes on that bastard.

staggard 20's come stock on the 4.6is

I am running 19x8.5s with 265-50 Pirelli Scorpion Ice and Snows for my winters during ski season here in CA.

Yep those 20" are bad ass, new from Tischer back then cost $3500 w/o rubber for a set.

If you haven't replaced the WP with that kinda mileage it's due, so just do that with thermostat; I believe you'll get rid the leaks.

Also, the N62 uses Vlavetronic. A complex system that infinitely varies intake valve lift. Thus the "intermediate levers" issue you've probably read about. The M62 is standard DOHC with double Vanos.

-Ben

Check your lower rad hose. There is a plastic Tee fitting for temp sensor that cracked on mine - drip was about 1/2 way between front of motor & back of rad.