1993 100cs coolant overflow tank ?
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AudiWorld Newcomer
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1993 100cs coolant overflow tank ?
Ok so i replaced my coolant overflow tank about 4 plus weeks ago, and recently noticed it is starting to leak out of the hole that is kind of hidden in the middle of the bottom, I know that hole is suppose to be there to help relieve pressure or coolant if necessary i believe? I am going to replace the cap to see if it helps. If it doesn't any ideas on what could be causing this? I loose about half of a gallon out of the reservoir every 3 days or so. Maybe thermostat is going, or water pump, or radiator? also my temp gauge never goes above the half way line. the coolant light did come on once but was because tank got to low(i filled it back up and went away), so something is causing the overflow tank to push coolant out of that hole. ideas and thoughts
Thanks
Thanks
AudiWorld Senior Member
Joined: Jul 2013
Posts: 1,331
Likes: 33
That hole in the middle is part of a safety drain. If the coolant boils over..it goes out the bottom not up. Keeps you from getting hurt.
Sounds like your coolant is boiling..at least just enough to burp out.
A defective cap will do this for sure. If you can find a Febi cap..they seem to work best theses days..Pelican Parts has them part number 02269-INT about $5.
The anti-freeze to H2O ratio is 50/50..if your anti-freeze is too diluted with H2O..then you can have some boiling problems.
Make sure your radiator fans are working correctly..two speeds, low and high. And a sub-low speed with the A/C on.
You can check the fans by bridging the connectors on the radiator fan switch. Three wires there..Use a paper-clip and jump one connector to the (I think) brown wire..then the other.
If the fans work..try a new radiator fan switch. Let us know what temp range or part number you have. Should be a 87/92*C switch.
Sounds like your coolant is boiling..at least just enough to burp out.
A defective cap will do this for sure. If you can find a Febi cap..they seem to work best theses days..Pelican Parts has them part number 02269-INT about $5.
The anti-freeze to H2O ratio is 50/50..if your anti-freeze is too diluted with H2O..then you can have some boiling problems.
Make sure your radiator fans are working correctly..two speeds, low and high. And a sub-low speed with the A/C on.
You can check the fans by bridging the connectors on the radiator fan switch. Three wires there..Use a paper-clip and jump one connector to the (I think) brown wire..then the other.
If the fans work..try a new radiator fan switch. Let us know what temp range or part number you have. Should be a 87/92*C switch.
AudiWorld Senior Member
Joined: Jul 2013
Posts: 1,331
Likes: 33
Some of the information on this link may be helpful. Testing the fan switch for sure.
SJM Autotechnik, Audi Technical Service Repair Information
SJM Autotechnik, Audi Technical Service Repair Information
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