tracking down a coolant leak - Troubleshooting - VWDiesel.net The IDI, TDI, and mTDI source.

• tracking down a coolant leak by orengutan on 14 May, 2010 06:37
• is there anything behind/between the water pump and oil pan on an aaz engine? any hoses above the pump but under the alternator that I can't see?
  
  I'm trying to find the source of a leak. it's usually a fairly quick series of drops (up to a cup) coming from between the water pump and the oil pan. I just had the pump replaced a few months ago, so I'm not really suspecting it at the moment.
• #1 by burn_your_money on 14 May, 2010 06:43
• Maybe this would help
  
  
  
  I would suspect the o-ring between the block and the water pump, the o-ring for the thermostat, the thermostat housing, where the waterpump mates to the waterpump housing or the waterpump drive shaft.
  
  Did they swap in the waterpump with housing or just the waterpump?
• #2 by orengutan on 14 May, 2010 06:56
• oring between the pump and block? you mean at the head coolant flange? I just replaced that one last night. it *was* leaking, but this is a separate leak
  
  I assumed the thermostat housing is the above mentioned flange, right? since it had the two sensors in it.. unless there's another one?
  
  I think they just replaced the pump and not the housing, but I dont remember. I'll have to check.
• #3 by orengutan on 14 May, 2010 06:59
• I forgot to mention two factors:
   - I sat in hot traffic for over an hour (my commutes are usually around 20 minutes at a time) the night before this issue popped up
   - one of my fuel lines was leaking a bit for a while, so I'm thinking that some fuel got somewhere it shouldn'tve and now its a leak.
• #4 by burn_your_money on 14 May, 2010 07:04
• Quote from: orengutan on 14 May, 2010 06:56

  oring between the pump and block? you mean at the head coolant flange?

  
  Nope. There is an o-ring between the waterpump housing and the engine block.
  
  

  Quote from: orengutan on 14 May, 2010 06:56

  I assumed the thermostat housing is the above mentioned flange, right? since it had the two sensors in it.. unless there's another one?
  

  
  That's not the thermostat housing. The thermostat housing is on the bottom of the waterpump just above the power steering pump.
  
  In this picture hose #6 connects to the thermostat housing.
  
  
  
  
  If you removed the power steering pump and ran the car you would probably find your problem. Unless you have AC...
• #5 by orengutan on 14 May, 2010 07:19
• oh. interesting. I didnt realize there's another thermostat, but it explains some things I was wondering about.
  
  I'm thinking I might replace that hose first and then worry about the thermostat, since the hose is probably easier to replace (and at least then I'll be able to rule out an IP related leaks...).
  
  
• #6 by burn_your_money on 14 May, 2010 07:42
• There is only 1 thermostat. The things on the flange on the front of the head are coolant temperature sensors.
  
  
  You would be wise to find the actual problem and correct it. While you have the coolant drained replace any other hoses that you feel necessary. Vw's coolant system is a pain to work with.
• #7 by orengutan on 14 May, 2010 07:45
• yeah. I translated both to the same word in my head
  
  so I was confused why there's two thermometers, but just accepted it as Fact.
  
  I'll try to replace that hose I mentioned first, then the housing, and THEN if the leak is still there, I guess I'll do the o-ring. may be wasteful and not so very cheap, but I'll be pretty happy if its just one of those hoses.
• #8 by orengutan on 19 May, 2010 12:17
• closure: it was the 3 way hose. the original one was ***ed right near the thermo flange, so I couldn't see it. leak fixed.
  
  thanks guys
• #9 by burn_your_money on 20 May, 2010 09:59
• Good show. Thanks for following up.
• #10 by orengutan on 20 May, 2010 11:22
• while I'm here doing closure, I should point out that even if you think your car has leaked dry, it hasn't. I definitely had at least another liter in there after I thought it was empty and took off the hoses.
  
  good thing captain planet wasn't around.
• #11 by mystery3 on 20 May, 2010 21:39
• Unless you pull the thermostat the coolant never fully drains.
  
  Ethylene glycol coolants are not very dangerous to the environment in small quantities, chemically very similar to alcohol. You should dilute it ie: hose down the area to prevent animals/children from drinking the sweet blue liquid!