brassman96

Hi folks,
I am a new 5 series owner with a 2008 528xi with 103,000 on it. I am replacing the coolant pump and thermostat. What hoses should I replace while I am in there? There are quite a few. Which ones are problematic? I already have new upper and lower radiator hoses. Already did the little expansion tank to radiator hose when it let go not long ago.
I will replace the serpentine belt, tensioner and and pulley too.

Thanks!

tstiglich

2009 528xi here. There is a hose that connects to the front of the engine block via a plastic end connector. This plastic piece is a known failure point. Either replace the hose (end plastic piece comes attached), or get a new hose and use this for the connector:

https://www.fcpeuro.com/products/bmw...e-rein-chc0609
https://www.fcpeuro.com/products/bmw...in-11537544638

Note: Those are for my car, may not be the same as yours.

Ignore if this hose is either the upper or lower radiator hose.

If you are going to replace the belt and tensioner, I would recommend replacing the two oil cooler gaskets. A very simple and inexpensive job. Also, a known failure point. Replace BEFORE the serpentine belt work.

I also suggest that you read the document for new BMW owners here: https://www.bimmerfest.com/forums/sh....php?t=1253416

brassman96

Thank you very much tstiglich!

brassman96

Just saw that the previous owner had the oil cooler gaskets replaced at 60,500. They still look good. Do'em anyhow?

kd7iwp

I agree about the mickey mouse styled connector on the end of the hose at the front of the cylinder head. I didn't replace the hose, just bought an aluminum fitting from Amazon to put on the end of the hose. I personally haven't replaced any other hoses on my 2001 E46 or my 2009 E61. I find that hoses seem to last a long time. None of mine feel brittle or thin anywhere.

brassman96

Much appreciated!

tstiglich

As for the gaskets, up to you. Just keep an eye on them. When they leak, the leak onto the serpentine belt. Belt then has a tendency to come off and get wrapped around the crank pulley, then sucked into the engine itself. No joke.

tstiglich

If the transmission has not been serviced, you may want to drop the pan, replace mechatronics sleeve, sealing sleeves, and the rubber rectangular thing whose name I can't seem to remember. ZF, the maker of the transmission, recommends fluid drain and fill every 60k miles.

brassman96

"Belt then has a tendency to come off and get wrapped around the crank pulley, then sucked into the engine itself. No joke"

Yeow!

brassman96

tstiglich wrote: "If the transmission has not been serviced, you may want to drop the pan, replace mechatronics sleeve, sealing sleeves, and the rubber rectangular thing whose name I can't seem to remember. ZF, the maker of the transmission, recommends fluid drain and fill every 60k miles."


Forgot to mention, I bought all the goodies to do just that. Thanks for the confirmation. Did some reading on the acceptable ATF fluids and it looks like Pentosin is good quality and reasonably priced. The BMW and ZF brands are pretty spendy.