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Once the engine warms up and the cooling system builds pressure, I get a steady drip-drip from the area of the coolant level sensor on the under side of the expansion tank. Anyone BTDT?
Do I (1) replace the sensor? (2) Just replace an O-ring on the sensor? (3) Permatex the crap out of it?
Seems like whatever seals the sensor against the tank can't withstand the pressure. The tank is only ~3 yrs old.
Looks like the coolant level sensor is built into the expansion tank and isn't meant to be pulled out. So a leak at the sensor means time for a new tank. They can be had for ~ $27 at autohausaz.com. It pays to shop around. I saw them advertised for $60 on some other sites that are typically competitive on price.
The sensor looks pretty delicate and I bet is easily damaged by pressure spikes. So be sure not to overfill that tank!
The coolant level sensor is integrated in the tank
and is probably not the source of the leak. I bet the coolant is dripping down the center hole in
the tank and then off the sensor. Check the cap seal for the leak. The plastic trim piece around the cap will pop off to better see any leak down the center hole.
Please don't post to the archives because you are giving yourself bad advice. The aftermarket expansion tanks are of poor quality and known to fail within a year. Genuine Audi parts for the
tank and cap are your best choice. Just look for the best deal for the dealer part such as www.
genuinevwaudiparts.com.
I agree that the sensor is a low-point on the tank and liquid from a leak elsewhere would likely travel to the sensor and drip from it. That's not happening in my case. The leak is directly where the sensor seals to the tank. Nothing else is wet.
Good point about OEM vs. aftermarket. The cheapest tank was a Meyle...
are not priced too badly from the discount dealers, but the cap price is insulting but still
recommended since you really want to get past these annoying leaks. There is nothing
worse than having to stop prematurely during a scenic mountain drive because the coolant light and warning beep keep disturbing you and your passenger at every summit and sweeping curve.
Not only does it erode the faith of your passenger in your vehicles road worthiness, but also your abilities to properly maintain this beast, not to mention knawing at your self confidence and your wallet.
Well, one thing worse is having the adapter to the heater hose on the head or the coolant sensor "T" fitting fail, requiring immediate action to prevent engine damage and have no place to pull off the road. This will really interrupt a trip.
If this sounds like personal experience, just double that, since I installed two Meyle tanks and fresh coolant at the same time, mostly for cosmetics, and had both tanks crack and spring leaks in less than one year.
The coolant will usually only leak when hot and pressurized, so small leaks will evaporate before
you can examine most areas. If you are using Audi coolant (or Pentosin) it leaves a distinct white trace to pinpoint the leak. I would wipe the area clean and examine closely before deciding the source of any leak, especially here, where leaks around the level sensor are rare, but releases at the cap vent or gasket are common.
Could this be an aftermarket tank already installed?
The installed tank is OEM. I got a chance to inspect a Meyle tank at the local parts store this morning, and I agree it's not an ideal substitute. I'm pretty sure the leak is from the sensor area since there are no residue trails or stickiness on the exterior of the tank BUT there's ample white residue directly below the sensor where the coolant has been landing.
The installed tank is OEM. I got a chance to inspect a Meyle tank at the local parts store this morning, and I agree it's not an ideal substitute. I'm pretty sure the leak is from the sensor area since there are no residue trails or stickiness on the exterior of the tank BUT there's ample white residue directly below the sensor where the coolant has been landing.
I just didn't want you to base your repair plan on a quick look at the leak. The tank is probably
original and maybe due for a change on looks alone or the small nipple at the front.
I pulled the expansion tank off and there is literally nothing else there where the fluid could be coming from. I put a brand new tank on and still the same issue. Can you buy the sensor separately? I dont see how it can be put on without rewiring...
The aftermarket expansion tanks are of poor quality and known to fail within a year. Genuine Audi parts for the
tank and cap are your best choice. Just look for the best deal for the dealer part such as www.
genuinevwaudiparts.com.
The one I got failed the first day! Wasn't worth the shipping cost and hassle to send it back. If the tank is more than a few years old, it's probably going to start leaking in the nipple area fairly soon anyway.
11-05-2009, 04:10 AM
coolant level sensor leaking...
