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coolant reservoir bleeder screw leak

5334 Views 4 Replies 3 Participants Last post by  CSMBlack-540i
Hi guys. I've got a question based on a 2003 525 with 145,000 miles on it. Around 10,000 miles ago, I did the full cooling system overhaul as recommended based on CN90's and Bluebee's posts/recommendations. (Great information as always!) Occasionally when I park the car after a drive of greater than 15 minutes, I get a strong smell of coolant, the sound of a few drops of fluid dripping onto a hot engine component (I'm assuming coolant), and a small pool of coolant on top of the coolant reservoir bleeder screw. I never see any coolant or fluid of any sort on the ground afterward (Except for A/C condensation which it has always done). Everything else appears to be functioning correctly, car is not overheating, engine compartment is dry, and like I said these symptoms appear only occasionally (Once every couple of days). My questions are, what is the purpose of the bleeder screw at the reservoir, is this a common issue, do I need to bite the bulllet and buy a new reservoir or is there a simple fix to the leaky screw, and does it sound right that a small leak from the bleeder screw could somehow blow coolant onto hot engine components but not have any drip onto the ground? Am I overlooking a bigger issue/leak somewhere?
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Welcome to the forum.

A bit confused. You mentioned a full cooling system overhaul but then mention biting the bullet to buy a new reservoir.

Did you replace the bleeder screw and reservoir with your overhaul.

If not what did you actually replace in the overhaul?

Also what brand reservoir is currently installed?
at 150,000 my thermostat bleeder screw broke in half. I had to heat a screw driver tip and stab it into the broken bleeder screw to twist the rest out. I replaced them with brass ones two years ago.

http://www.autohausaz.com/search/pr...ooling System&[email protected] Bleeder Screw
dvsgene - During my cooling overhaul I did completely replace the reservoir and bleed screw as well as the fan clutch, blades, water pump, thermostat and housing, hoses, belts, tensioners, etc... I think the replacement reservoir I bought is the Behr version (it's been a while). I know the reservoir is fragile, but 10,000 miles to failure seems exceptionally weak. As lame as this sounds, I jumped right past it being a failing screw and assumed that the tank itself was the problem (based on their reputations) so I think I'll start with the screws and go from there. Thanks.
Ok, thanks for clarifying.

Just checking as another member had a similar issue yesterday and the reservoir was 1 month old. After asking the brand, turned out to be a Dorman aftermarket.

As you know even Behr has issues these days, while 10,000 miles is a short amount of time/miles. Based on recent forum feedback, it is not uncommon for less than 1 year old Behrs to fail. Many have recommended buying the Behr at the dealer instead of the aftermarket Behr from online vendors.
dvsgene - During my cooling overhaul I did completely replace the reservoir and bleed screw as well as the fan clutch, blades, water pump, thermostat and housing, hoses, belts, tensioners, etc... I think the replacement reservoir I bought is the Behr version (it's been a while). I know the reservoir is fragile, but 10,000 miles to failure seems exceptionally weak. As lame as this sounds, I jumped right past it being a failing screw and assumed that the tank itself was the problem (based on their reputations) so I think I'll start with the screws and go from there. Thanks.
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