BMW Genuine Radiator Expansion Tank E46 E53 E83 17117573781

Product Information

you that the thermostat in the bottom is for the automatic transmission cooler? And that it will probably break in the removal process. I believe it's brittle and

First one, 16mm inside diameter x 3mm width: This is I think only one per car, fits the fitting on the upper radiator hose where it plugs into the expansion tank. (NOTE: I also tried a slightly larger O-ring for this one, size 3.5 mm Width, 16 mm ID, and I absolutely COULD NOT manage to get that one to seat in the groove in the hose fitting! Third one, 4 mm Width, 38 mm ID, is the biggest, fits upper and lower radiator hoses plus the larger of the two fittings on the bottom of the expansion tank, I think that makes 5 per car. Last time I took everything apart I took a photo of it all, and wrote a lot of notes, and flow lines etc, just to remind me next time I have to work on it. I've included it below. So...what you will need to do...is remove two torx screws indicated on the below drawing, by the red dots.

not to discredit the previously posted links for o-rings, but below is another option that includes actual o-ring sizes. Radiator part number 17119071519 (depending on the brand be sure to get a proper adjustment screw for manual or automatic transmission) I thought this is unbelievable, why, how is this thing (tank) still in here? Pull, Pull and wiggle, pull some more! Man. How to pry it off from the lower connection? Nothing fits to do that, Pry bar from the frame to the bottom of the tank almost works. Remember the slow and easy pulling, you will break the thermostat in the bottom if you man-handle it. I think it's like an egg shell, touch it and it will break. Vehicle models change and evolve, as they grow older, so the vehicle shown in our illustrations may vary slightly from yours. If something seems different, let us know and share your info to help other users. Do you have questions or want to add to the article? Leave a comment below. When leaving a comment, please leave your vehicle information. Since the main belt and pulley assembly is responsible for so many vital systems, it is extremely important that it stays well maintained. The primary belt is guided by a pulley that contains grease to keep it lubricated. Typically this grease dries up around the 60,000-mile mark. When that happens, the belt can either become misaligned, slip off, or snap. At that point, you’ll be without power steering, an alternator, or a cooling system. E46 Belt and Pulley Failure Symptoms

Installation meant some modifications: I drilled two holes into the plastic parts under the expansion tank, and used few screws to connect the new tank. When the coolant spilling from the bleed screw is free of air bubbles (just a steady stream of coolant), tighten the screw and replace the expansion tank cap. It's a well known fact that the expansion tanks on E46's can be very stubborn to remove. I had read somewhere else, that pulling the "BMW expansion tank retainer", PC 10, below....then removing the expansion tank from PC 10, when it's out of the car...may facilitate easier removal. So That's what we did. I just took a bunch of pictures....which should describe what you need to do.

Once the assembly (Retainer and Expansion Tank) is out of the car, it can be separated rather easily.