Drip..drip. un-cool(ant) situation

[Ogopogo]

Well, I appear to be getting a little closer to finding the source of the coolant leak that’s been causing my X to pee all over the Garage floor. The puddles have been showing up near the back of the engine. They appeared to be a little more right of center, but that may have been skewed due to drips hitting the skid plate, and finding a way out from there. I was really hoping that it might have been a hose failure around the back/rear of the engine, but no dice. I pulled apart the cabin filter shrouding (three times), and poked around with a light and a mirror. Hoses in good shape, and drier than a popcorn fart.

Another interesting thing, it takes the leak hours to show up. I had been backing off the cap on the coolant reservoir, trying to relieve pressure, and minimize the coolant lost, but this didn’t seem to make much difference. I would look under the rig 3-5-8 hours after parking it… nothing. Next day, a good sized puddle appears (+/- 1/3 cup).

Yesterday, I jacked it up and slid under and found (sort of) the smoking gun. Yellowish green coolant dripping from the bottom of the Bell housing. It almost looks as though it’s coming from inside the housing itself. So, the question is: is this an obvious Valley Pan failure, or potentially something else?

I’m planning on going the DIY routine on this. I’ve read TwinTurboGTR's write up on the VP gasket and Valve cover gaskets several times (great job!). My Valve covers are not in too bad of shape, so I think I just want to address the Valley Pan right now. Is it out of the question to re-use the EGR Valve and Oil Separator, or is foolish place to save some money?

BTW it’s an ’02 4.4l w/112Km (70k Miles). I know many of you will suggest doing the water pump at this point, but I’m not really prepared to do it at this time.

So, if I were to re-use most hoses etc. the bare bones parts list looks like:

• Valley pan/cover
• O-rings (4)
• Intake Man. To Throttle housing gasket
• Intake Man. To Cylinder head gasket (4)
• Water accumulator gasket

Let me know if I’m missing anything, or if you feel strongly that I should rethink re-using some of the parts that I mentioned. Also, the coolant currently in the system is yellow/green, the BMW stuff is more blue in color, are they going to play nice together?

Thanks.

[upallnight]

Behind the intake manifold are several coolant line that could your problem.

[HPIA4v2]

There are two coolant-manifold gaskets (item #2 on the picture) where the two coolant pipes connect to, these also become fray/dis-integrate over time, I'd replace those as well.
As for WP/thermostat, I'd replace them if I were you, not bad in terms of cost but you have to remove them to get to valley-pan, unless you like to wrestle with those two pipes next time around (they are hard to get and put back into, I had pinched the o-rings and had leaks).

[bcredliner]

as per upallnight, most likely source are one of the coolant hoses at the back of the engine, on top, at the firewall and down the firewall where they are hard to reach. Check the hoses with your hand after you have seen coolant on the floor. If a hose is leaking you should be able to feel which one is wet. If a hose is leaking it should be replaced as soon as possible. It could split open on the highway and you will be stranded as the engine will quickly overheat. The leak could be at the clamps but when that happens it often means the rubber is breaking down and still should be replaced.

Good rule of thumb is to replace all 'minor' parts associated fairly big disassembly that have a 'limited' life and you can't get to unless you do all or most of the same disassembly again.

[Ogopogo]

I'm pretty satisfied that it's not one of the hoses/accumulator gasket at the back of the engine, as I've inspected it several times and see no evidence of leakage. The only spot I can track down some actual dripping coolant is at the bottom of the Bell housing on a cold engine.

Is that an obvious sign of a Valley Pan failure?

I might be rolling the dice a touch by not wanting to swap out a bunch of other components, and I might regret it, but I just want this beast to stop pissing on my garage floor. Frankly, I'm not sure I want to go to a lot of effort and expense on a vehicle that I might not own for more than another 10/12,000Km.

Cheers.

[bcredliner]

Yes, a leak like you have usually indicates a VP gasket and a VP leak is a 'common' X5 happening. Since a VP gasket replacement is a big job you might want to rent a cooling system pressurizing tool before you tackle the VP job to see if you are lucky and find the leak is coming from somewhere else.

[RuhRoh]

I had the same type of leak when I first got my 01 4.4 about a month ago. After about a week it stopped. So not sure what to think. But after cruising the forum a while I came across a link to this YouTube video about changing the VP gasket and in it he shows just where the leak occurs. It's not a step by step DIY but it has some great information on changing the gasket including tip on doing the work without pulling the WP. When I get ready to tackle mine (I need VC gaskets too) I'm going to use his tips for sure. Plus it gives you some encouragement as it doesn't look too difficult.

Good luck and let us know how it turns out.

BMW M62 Valley Pan Gasket Replacement - YouTube

[jst2878]

valleypan, definitely. and while its all opened up get the two coolant tube orings and the epair for the front of the tubes and check your water pump, might as well change since its all apart. have fun with this labor intensive job

[Ogopogo]

Thanks for the input. jst2878, I thought about changing out the w/pump, T-stat, but those items add substancially to the complexity of the job (removing belts, pulleys, reservoir, etc). My plan is to keep it as simple as possible and replace only the deliquent/necessary parts. That means: V-Pan/cover, gaskets, O-rings, and Coolant.

I've had the rig for only about two months, and so far have had to do the Reservoir tank, front axel half shaft. Still need to do the Thrust arm bushings/alignment, change oil and spark plugs. More work than I had hoped for, especially since it's got just barely 70K miles. Now, every time I see a similar vintage Acura MDX, on the street I silently curse myself for not going that direction instead....DOH!

[Ogopogo]

I'm putting together the parts order for this job, and could use a little input from those that have done it before.

I'm wondering if replacement of the CCV (intake manifold cover) and OSV (oil seperator) is uber critical or not?

Is it a:
1) "If it aint broke, don't fix it"
2) You'd be a damn fool not to!

TIA