Mysterious Coolant Loss
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b5 a4
Mysterious Coolant Loss
I have been struggling with this for a while so I might as well throw this up here.
I have a quite modded c32. Supercharger is of course isolated running through a tank and not using valves off the stock resvoir.
Every month or so I lose about half of what's in the coolant tank. Top it off and it will be good for another 3-4 weeks before I get add coolant msg.
things I have done: Upper and lower hoses, Code 3 thermostat, Radiator for oreilly when I bought the car 2 years ago, new tank cap. Used heater core block off caps on tank to separate intercooler.
My thoughts: Rest system?? Maybe the headlight washer warmer in the tank?? Leaking into trans from a new radiator --__-- or the worst of all......headgaskets.
please help me out!
I have a quite modded c32. Supercharger is of course isolated running through a tank and not using valves off the stock resvoir.
Every month or so I lose about half of what's in the coolant tank. Top it off and it will be good for another 3-4 weeks before I get add coolant msg.
things I have done: Upper and lower hoses, Code 3 thermostat, Radiator for oreilly when I bought the car 2 years ago, new tank cap. Used heater core block off caps on tank to separate intercooler.
My thoughts: Rest system?? Maybe the headlight washer warmer in the tank?? Leaking into trans from a new radiator --__-- or the worst of all......headgaskets.
please help me out!
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Joined: Jun 2011
Posts: 601
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From: I liva at da land down under
Porsche 2004 911
I am no OG mate - the splinter's,crazy's,gramma's,lenin's,dirty's,scott' s,robert's,pansu's,tw2's, newspzshpys etc etc - have the real knowledge. I do know that I replaced pretty much everything on the car and then the engine and started all over again. If the coolant reservoir cap has been replaced and there is no coolant residue on the tank or pipes/ hoses(isolated) and throughout cooling system,no perished hoses maybe check the surge tanks for coolant residue and get indie to pressure test the cooling. Mine was frustrating- I had a similar amount of coolant loss that you have- tested and found no leak, replaced coolant res and cap, double checked all hoses, no residue in surge tanks - it was the IC but was not found under pressure at low engine temperate, only at high engine temperate it would leak. Replaced the IC then a couple of months later blew the engine, sold the used IC and bought a new IC (spare) and a low km engine. Before we dropped the engine in went through everything and replaced all the new(ish) parts that were on the original engine. I had no intention of selling the 32 but a mate upgraded his car and I picked up his 911. I sold my 32 (for a steal) to a first car owning relative and only issue that lucky bugger has is to replace the rear tires. Every month I owned the 32 it was a pure thrill but usually ended up broke. 
Sincerely hope you find the fix and if my dribble doesn't assist, the senior members will chime in and point you in the right direction hopefully. They helped me far too many times.
Sincerely hope you find the fix and if my dribble doesn't assist, the senior members will chime in and point you in the right direction hopefully. They helped me far too many times.
Last edited by macbryanie; Jan 27, 2016 at 08:28 AM.
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b5 a4
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W203 C32
have you look at the reservoir? itz a 10+yr old plastic that gets heat up and cool down alot, and it might sip out bit by bit? from my experience from a lot of european cars, they tend to be pressurized after coolant is fully heat up to op temp. my gti reservoir exploded half way driving to work, and my saab had that problem too, and I have seen my friend's w203 non amg had a tiny crack at the bottom of the reservoir.
Do you smell the coolant smell after a 20-30mins drive? if it is sipping out from water pump, you will definitely smell the coolant smell for sure.
Last, have you worked on the car within the last couple months? maybe as you work on the car, u accidentally loosen a hose somewhere or near by? Does any of the covers underneath show any sign of water marks? This thing has covers everywhere, couple drops here and there get dried up pretty fast.
Do you smell the coolant smell after a 20-30mins drive? if it is sipping out from water pump, you will definitely smell the coolant smell for sure.
Last, have you worked on the car within the last couple months? maybe as you work on the car, u accidentally loosen a hose somewhere or near by? Does any of the covers underneath show any sign of water marks? This thing has covers everywhere, couple drops here and there get dried up pretty fast.
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b5 a4
I don't visibly see or smell any coolant. I'm thinking it may be the water pump as a MB tech stated that m112 water pumps leak slowly from the weep hole when going bad. This would make sense as the coolant will have dried by the time it escapes and also that it takes such a long time to lose enough coolant for the light to come on.
Super Member
Joined: Jun 2011
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From: I liva at da land down under
Porsche 2004 911
If you replace it - go with the OEM (bosch i think)
I replaced my water pump early in the ownership of 32 (car was 9yrs old it the time/original pump) with an aftermarket (it died after about 2 years)then later replaced with OEM.
