Not your typical coolant leak

[X5chemist]

Other an OEM, the high end M54 Stewart water pump looks appealing. More flow and great company.

https://www.bimmerworld.com/Cooling/...p-E36-E46.html

[Aidzer0]

Originally Posted by X5chemist

Other an OEM, the high end M54 Stewart water pump looks appealing. More flow and great company.

https://www.bimmerworld.com/Cooling/...p-E36-E46.html

I’ve seen those, I’ve heard of guys running that without tracking their cars and they ran into issues with over-cooling. I don’t have actual proof for that though.

[workingonit]

Originally Posted by Aidzer0

I’ve seen those, I’ve heard of guys running that without tracking their cars and they ran into issues with over-cooling. I don’t have actual proof for that though.

Over-cooling in Texas summer heat wouldn't be a problem...I was always trying to achieve just that effect, whether on my daily drivers or my drag-racers. Especially on my pickups, which were dual-use, daily driving and towing.

Over the years, I tried "high-perf" water pumps (such as they were, not many nor actually hi-perf), and found name brands with quality control problems (seals, shaft run-out), so I always added supplemental electric fans whenever and wherever I could, even on my wife's old '92 Olds Achieva SC Quad4, '88 Pontiac Fiero 4 cyl., and her '85 Chrysler Lebaron 2.2L turbo (she had this thing for oddball cars). The combination worked in stop & go traffic and in long staging lanes (both in <100F).

If I'm not mistaken (my memory isn't what it used to be), both my '98 GMC and the 327 c.i. engine I used in my Chevelle in the late'90s (on a furniture dolly in the garage, unused for 22 years) each sport Stewart water pumps.The one on the GMC was installed by its' previous owner in 2005, before I bought it. Good pumps.

However, there have been exceptions to adding a hi-perf water pump and a supplemental fan to my vehicles (not counting the 3 air-cooled VW's I had in the early
70's):

• 1) I used a 55 gpm electric water pump on my last two racing big block Chevy engines, as they could be switched on/off as I wished. I had two radiator and one transmission radiator fans (dedicated radiator/fan combo, placed behind a deleted headlight) on them, as well.
• 2) My '04 Chevy 2500HD WT, with a mechanical fan cooling the 6.0L, has never given me a hint of overheating, though it has endured the heaviest duty, and heat. I love that LS engine.
• 3) Our '08 Cobalt and '09 HHR Panel, both with Ecotec Gen 1 engines. The factory fans have kept our daily drivers cool (unaided by extra fans) for nearly 300k miles (added together). Then single overheat episode was after I didn't burp the air out of the HHR after re-filling, and it got to 242F just as I got to the house. No damage, though.

As for my X5, the first thing I repaired/replaced was the cooling fan. I removed the mechanical fan and installed a 3000 cfm electric fan. I didn't get an accurate temperature reading for the coolant while the mech fan was still on (I took off the old fan with broken blades before I had driven 10 miles), but the new electric fan always keeps the M54 cooled to 194F (+/- 3 degrees), at all times. Whenever I get around to a new water pump, I'm gonna get the Stewart, for sure. A perfect combo, IMHO.

[X5chemist]

The Stewart pump is an option for a future fan clutch delete. With A/C use all the time in Texas, I don't have to worry as much about programming gauge readings.