I posted this in the General Discussion section and figured I'd post here too, might get some advice from all you Tech folks, thanks!


Hello all, 2005 A4 Z51 with 28K miles. Bought the car 5 years ago with 10.5K miles, had the engine oil, trans oil and anti freeze changed at that time. Over the (very bad) winter I noticed an occasional drop or two of coolant in the drip pan, didn't really drive the car at all this winter. Since I'm driving again the drops seemed to have stopped although I noticed one yesterday. Haven't added any and the level appears to be constant although I occasionally get that anti freeze smell. Do you all think it might be time for a cooling system "tune-up", new hoses, fluid, thermostat? I've felt around the water pump and all feels dry. Just wondering if the hoses, because of old age might be subject to shrinkage and maybe a little leaking. And what type of job to change the hoses, a big deal? Definitely gonna change the fluid but wondering about the hoses and thermostat. Any other advice/input would be appreciated, thanks! One other question, silicone hoses, worth it or not? Gates or Dayton hoses gonna run around $150, silicone online around $300, not a problem going with silicone if they are that much better...thanks!

 

If the drip is occurring near the front of the engine it probably is the water pump. Are you getting fluid on the front stabilizer bar. If you have pump leak the area behind the pump pulley will feel sticky if the pump isn't leaking at that moment.

The pump on my 08Z leaked but it was hard to determine what was going on. Neither I or the dealer mechanic could find the leak. Then one day I had the car on the lift doing some track preparation and went inside to eat lunch. When I went in the floor was dry and when I came out it was wet. The engine hadn't been run in over 24 hours. That is when I saw the coolant on the stabilizer bar, the bottom of the crankshaft pulley and the normally dry but sticky area behind the pump was wet.

Bill

 

Thanks Bill, although I haven't gotten under the car yet it appears that the leak is from the middle of the engine right side. I have a large drip pan under the car and it doesn't look like it's coming from the front of the engine. I see the heater hoses run along the right side and I've felt them, all is dry. I've read about the freeze out plugs leaking, gonna put the car on jacks and poke around. I got the car inspected last week, asked the mechanic (a Corvette guy) to check but he couldn't find anything. Strange thing is it hasn't leaked since I started using it regularly then the other day a SMALL drop, about the size of a dime. Thanks again...

 

Are you absolutely sure that the drip is coolant?

 

No doubt, definitely orange coolant.

 

Frontal drips often misdiagnosis as failed water pump.

Sometimes it could be the two gasket. They are marginal at best. Over time, it will shrink and fail to provide seal function.

My '05 had a coolant smell no visible leak or coolant level drop. Beside checking the obvious bottom of water pump drive pulley, further exploratory revealed it was the two gaskets. One simple way to check without removing the complete water pump is to remove water pump fastener, one at a time, look for a tale tale sign. If removed bolt is flawless, reinstall and retorqued. Body of water pump bolt should be free from corrosion - corrosion = gasket is not doing its job.

I changed out my 9 year old, less than 28K miles, '05's gasket last year. I put a very thin coat of anaerobic gasket maker on both gasket surface before reinstall for long term peace of mind.

 

I'd hate to do all the work to replace hoses, thermostat, etc if you're not sure 100% where the leak is coming from. I would try and pick up a cooling system pressure tester. Maybe rent one from auto zone, or find a cheapo from horrible freight. That might help pinpoint your problem.

 

I agree. I would not replace parts without a proper diagnosis. Buy or borrow a coolant system tester. It attaches in place of your radiator cap and has a pump and pressure gauge.


Make sure the area under your car is clean. Mark the position of the front tires. Attach the pressure tester and pump it up to 15psi. You may have to let it sit for an hour or two and then check for leaks.

 

Working with cars long enough, some of us, using educated guess can isolate simple symptom/problem with fair accuracy and without specialized tooling.

Although, hard to deny proper tooling dedicated for the job is helpful for both amateur and professional, to positively confirm an educated guessing of an existing gremlins in a more complex situation.

Good luck op!

 

Thanks, it might come down to this, I never thought of that. I'm probably gonna change the hoses (original), coolant (due now) and thermo (original) anyway as it's time but would like to isolate the leak before I pull the hoses, if it's the water pump I'll change that while I have all the hoses off. Had the car idling for an extended period the other day, wanted to heat it up good hoping I could see something pissing out, couldn't find anything. I did find a little orange residue on the inside of one of the heater hoses at a bend, pulled, yanked, twisted, squeezed, did everything I could to make that hose leak, nothing. Looked around to see if something could be spraying coolant in that area (it's adjacent to the water pump), couldn't see anything. Did add the slightest little bit of coolant today but car ran great (as always)! Thanks for all the input, dealing with a health crisis with a family member right now so not really able to spend any time under the car yet!

 

Before you start randomly changing out hoses and the pump, I would check the small hose that comes off the radiator reservoir. The T-connector that is connected to this hose tends to become brittle and break. the T-connector is in front of your power steering pump almost directly under you MAF sensor. If it is this connector, it is a very cheep fix.

Hope this help you out