Thermostat reliability

[mferek]

+1 to all of the above! so +....12?

[Joshdub]

I would also suggest a metal impeller water pump but not URO. I avoid URO like the plague.

[Scott ZHP]

Originally Posted by Joshdub

I would also suggest a metal impeller water pump but not URO. I avoid URO like the plague.

I do too, normally. Just to clarify for the OP, I wasn't suggesting a Uro water pump. Just the pulley, as it's surprisingly good quality.

I have not seen an M54 water pump with a plastic impeller in years. The pump to have is the Stewart, but it's three times the cost of a Graf. I have one on my 330i; it's warrantied "for life", whatever that's worth.

[80stech]

I replaced the tensioners/pulleys already with INA units. Would the crack in the water pump pulley be visible before removing? Is the aluminum one considered an upgrade ?

[80stech]

Ok, I didn't realize the original water pump pulley was plastic! Yes, already have the water pump with metal impeller ready to go. Good to know that wahler is the OE for the thermostat but too late, already ordered the BMW for almost double the money, crap ;( I didn't want to take a chance on that. The expansion tank on mine looks like it might have been replaced, looks newer and has BMW parts sticker on it. Did BMW have a change up on the expansion tank ?

[80stech]

And yes have had the E30 cap ready to go but haven't put it on yet. up till now I never noticed much pressure in the cooling system. Seems as if you run the level on the low side the pressure never gets close to what the cap is set for. I Imagine might be different when the weather gets hotter though. I do want to still rig something up for the low coolant level sensor as well.

[bmw540san]

While it's theoretically ingenious idea to vary opening temp through DME, I don't like potential issue behind it when heater fails or leaks and coolant makes its way up through the wiring and cause havoc.
Yes, it's rare and only happens with M62TU thermostat, but M54 thermostat is not that much different when it comes to that feature.
Therefore, I went backward in technology and installed 95 C thermostat found on E31 840ci with M62 non vanos engines.
With a simple radiator hose modification and along with Spal fan (fan clutch delete) my X5 runs around 95-97 C with Spal coming on at 102 C if needed as a back up:
http://www.xoutpost.com/bmw-sav-foru...ch-delete.html

[80stech]

I don't know if I agree with the thermostat change over but the fan clutch delete looks like it might be a good thing. Mine seems to be working fine but does show a bit of leakage. I've heard some horror stories about the cheaper replacements and the BMW one is really expensive. I was leaning towards replacing with the Sachs clutch and maybe a new fan blade.

[cn90]

You need this:

http://www.xoutpost.com/bmw-sav-foru...16k-miles.html

[StephenVA]

Nice DIY posting by the way.

One more recommendation for the the HEPU Water Pump, I have one running in a 528 installed 5 years ago and it is happy happy happy.