Originally Posted by Skyline (Post 1132892)

If you're doing the coolant transfer pipe, it absolutely means you should do the water pump at the same time. Age and mileage says you should also replace every hose attached to the pump as well.

If you do the coolant expansion tank right away, replace the hoses for that at the same time. Keep in mind that if you ever remove a recently replaced hose for future repair, you should change the O-rings. Not sure if you can get these from BMW, but full sets are available on eBay. If you open the plastic coolant drain at the bottom of the radiator, have another plug on hand as well; again age and mileage. (It too has an o-ring seal.) Don't be surprised if it breaks when you try to remove it.

Again age and mileage, (mostly mileage,) plus your oil consumption; you probably need to do the valve guide seals. To confirm, idle the car for five minutes. Then mash the gas. If you see a massive cloud out the exhaust, it means the valve guide seals are shot. The only other thing than can cause this is if your CCV is not functioning correctly. At this mileage, most people have replaced this already. Biggest culprit is the rubber membrane in the valve on top of the valve cover, but the hoses do get clogged with mayonnaise if you do a lot of short trips in cold weather. To diagnose this more exactly, you can hook up a smoke machine to the oil cap, (I have a blue rubber Snap-on Blue Point smoke machine adapter that stretches nicely over the oil fill). Remove the intake elbow and plug the intake. (Most smoke machines come with a set of various sized yellow plastic disks just for this purpose). No smoke should come out. This might also detect a valve cover leak, (common), but you'll be doing those gaskets anyway if you do the valve seals.

I do agree that as others have said, the valve guide seals and the valley pan have very little overlap unless you plan to pull the motor. Doing both jobs, it might be worth it. Also, if you have access to the back of motor, you can use the original factory coolant transfer pipe, saving you $500 or so vs the AGA pipe. Not to mention the grief of cutting out the old pipe. It will make the valve guide seal job much easier as well, as several of the valves seals are REALLY hard in terms of access, (not impossible, just hard.) It's also very tricky to remove the valve covers on these cars without breaking anything. Both jobs can absolutely be done while the engine is in the car, but pulling the motor at your mileage can be a great opportunity to address a whole array of issues not discussed as well that are common to this engine, (like oil leaks from the front upper covers, oil cooler fittings etc.)

If you decide to do the valve guide seals, I do have the AGA tool kit for rent in the For Sale forum, send me a message.

Originally Posted by Nanniepoo (Post 1132902)

To be honest, I'm hoping to get another year or so before I need to do what I consider the "major work", as in an all weekend job. We're buying a house, which means I can finally get a proper garage with a lift. So in the future when I inevitably have to do the valve stem seals and valley pan/transfer pipe, I'd like to pull the engine and just do everything in one shot.

If things start going before that, I'll obviously have to address them. At the current oil loss I'm fine with just topping up. Haven't even tried some of the oil additives yet, and again have the PCV/CCV ready to be installed which might help. I understand the 5 min idle and floor it test, which would help confirm, it really wouldn't change my opinion since with our current driving habits the oil loss is rather minimal.

Originally Posted by Skyline (Post 1132892)

(I have a blue rubber Snap-on Blue Point smoke machine adapter that stretches nicely over the oil fill).

Originally Posted by Nanniepoo (Post 1132902)

At the current oil loss I'm fine with just topping up. Haven't even tried some of the oil additives yet, and again have the PCV/CCV ready to be installed which might help. I understand the 5 min idle and floor it test, which would help confirm, it really wouldn't change my opinion since with our current driving habits the oil loss is rather minimal.

Originally Posted by ard (Post 1132935)

Why?

Im trying to understand the rationale at changing oils and adding chemicals to address an underlying issue.(Arguably not really that bad an issue)

These additives are not without possible downsides, especially those that seek to modify rubber/polymers and cause swelling

Originally Posted by ard (Post 1132935)

Why?

Im trying to understand the rationale at changing oils and adding chemicals to address an underlying issue.(Arguably not really that bad an issue)

These additives are not without possible downsides, especially those that seek to modify rubber/polymers and cause swelling

Originally Posted by Jim Daniel (Post 1132962)

This thread started as a "coolant leak" (now it's oil and which additives to use).

Head gaskets can leak so slowly that owners can drive for years and never see a drop on the drive, or white smoke from the tailpipe. (just a hint of sweet smell).

Originally Posted by Nanniepoo (Post 1132963)

Neat but I found a leak so I'm not going to jump to the conclusion that I have a HG problem

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