qualitytop of the line aftermarket pump (Laso), In Canada close to $500 for rebuilt MB pump vs $150 for Laso (no core required) New pumps do appear to still be listed on-line - part number 1172003801. Rebuilt has slightly different number.

Graf was cheaper. Laso is, I am told German made. Graf Italy. Others like Meyle & Bosch China. Meyle rep suggested I buy the Laso, because it was most likely OE. Did not recommend their own pump! At least he was honest! Cardon offer rebuilds, but may need your pump.

Appearance of Laso and original essentially identical.

Re thermostats - Lower temperature ones just open sooner. Once open no affect. Best to stay with original spec of 75C. It is the area available for coolant flow when fully open that is important so buy an OE spec thermostat MB, Behr or Wahler. Not the Chinese knock offs sold by many vendors.

Your car won't die if you drill some holes, but question is - do you need to?

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Graham
85 300D,72 350SL, 98 E320, Outback 2.5

i found a Laso online for fairly cheap, just read an EPC article where they talk about LASO quality. i'll give this a try, thanks for the info as always Graham

http://www.epsparts.com/contents/show/Laso-Products-Information-Page

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W211 '03 E320 | W108 '72 280SEL 4.5

http://i66.photobucket.com/albums/h2...ps9b542eaa.jpg http://i66.photobucket.com/albums/h2...ps5723c50f.jpg

The intent for the drilled hole is to lessen the abrupt changes seen on the temperature gauge during the initial warm-up period. Since some drivers were alarmed to see their gauges jump to red line positions, then plummet, then return to red line several times as the thermostat opened and closed while the coolant was coming up to operating temperature, the drilled hole allowed small amounts of hot coolant to by-pass the thermostat thereby dampening extreme movements or the gauge. Naturally, the small bleed hole would have no effect once the thermostat was fully open, nor would this bleed hole be of any assistance with a general overheating problem for which one would have to address the entire cooling system. It is my recollection that the original poster was complaining about an excessive gauge reading on a short, 4+ mile drive, hence the suggestion about a bleed hole.