2005 Z51 A4, 30.5K miles...I bought it May 2010 with 10.5K miles, had the oil, antifreeze, trans oil and an alignment done. Time (actually overdue) to change the anti freeze again, should I also change the hoses and thermostat? I see an OCCASIONAL drop of coolant in the garage, have added a minimal amount once. Car temps between 192* (normal driving) and 212* (stop and go), hoses feel fine (firm) and look good. No unusual noises from the water pump...thoughts anyone? Not sure if there's a time limit on the hoses, x amount of years and you must change them. Thank you...

 

I would sure change the hoses (Gates) and put in a new 180 stat...Good Luck.

 

You could change the hoses, but I bet they're perfectly fine.

The one that seems to have problems long before the others is the plastic T intersection at the top of the radiator.

The leak is a problem. It shouldn't leak a drop. And with those low temperatures you're running, nothing should be coming out of the overflow. If the leak is from the radiator, it's likely that the stress of changing the hoses will make it worse. But that might be a good thing, because then you'll know where it's coming from.

 

Your leak is either the water pump or a crack in the left side tank on the rad.

 

You have the three things that are the most likely to have broken to produce the leak. The leak won't stop; it may get worse. I'd fix it. While the leak may not be attributed to a longer interval of fluid change, it could be. Fluids, once they start to break down, can go bad quickly, or even in their below-adequate state can be destructive.

As to the hoses I agree; you can change them altho they may not need it. Pat Goss (on MotorWeek) has said repeatedly for more than 10 years that today's hoses and belts are not "visual" meaning you can't tell by looking at them that they're worn out. I know on some Toyotas, belts and hoses go a very long time. Still, there comes a time when you're tempting fate unless you know for certain that a particular part was designed to last at least X miles or years, which we don't (or at least, I don't).

 

The first thing I would do is to make sure the drip is actually coolant and not condensation from the compressor on your air conditioner.

Next I would place cardboard down on the floor and determine the approx. location where this drip is occurring.

typical leaks in a C6 are as follows :

T-connection near the center right above your throttle body ... the fix is to get a generic T connection ( it will save you a ton of money )

the plastic end caps on the radiator ( can be tough to see ... may need to unbolt the cover and let the engine heat up and look for a small crack or steam or weeping .... some have claimed to be able to fix the problem with JB weld or other plastic welding .. I have never had any success and just replace the entire unit )

the water pump -- ( sometimes the leak is very tough to find as it seems the back seal often is the one that fails in the center )

 

Thanks for the replies, consensus seems to be change the hoses and thermostat so that's what I'll do. Hate to slide these ole' bones down under that car, I'd gladly pay to have it done but just can't trust anyone around here, hear good and bad about both dealers and Indy's so I guess it's on me. As to the leak, very perplexing, I have a drip pan in the garage and drip(s) seem to be right side maybe in the water pump/thermostat area. I've felt and looked all around and can't see a thing. I was underneath recently when I changed the oil and couldn't see any wet or stains (and it's definitely an anti-freeze leak, drips are orange colored). If I stop and park for awhile, when I pull out most times I'll stop, walk back to the spot where I parked and look for leaks on the ground, never find anything. Only seems to drip in the garage, maybe after it has cooled down a bit. I gotta get it way up into the air (maybe on ramps) and do some serious looking, thanks again, I'll keep you all informed.

 

Sometimes small leaks are not visible and only sign is coolant smell. An 11 year old car has loads of 11 year old consumable parts. Personally, as with my '05, I don't change parts just because it is 11 years old, I only make change out as needed. On the other hand, proactively, I changed out all my coolant hose to silicone when one of my oem hose was thinned out in one spot due to vibration rubbing and replacement of one hose having a molded "T" came close to a full set of silicone.

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Among other obvious coolant paths/joints. If there is no tell tale signs under the pump drive pulley bottom or visible rust behind pump drive pulley cavity...

Pull out pump mounting bolt one at a time to see if there is corrosion on bolt body, reinstall/torque if free of discrepancy...if there is...it is the pump gasket had failed.

OEM pump gasket contains an elastomer captivated within a thin aluminum flange to provide sealing over the two ports on each side of the pump. Elastomer could have suffered from age hardening and failed.

 

Bill: My Tundra is a 2000 which I bought new, has 104,000 mi. on her and I just changed the coolant out again (2nd time) about 3-4 months ago, I keep thinking I should change out hoses but I feel them and they feel nice and supple so since I don't use it for long trips, mostly around town I'm leaving them alone
So your comment on Toyota seems valid
NSF

 

Just a followup on my original thread. I finally got around to having the cooling system serviced, I found a very good Dealer mechanic who did the job for me at a reasonable price. The original very minor coolant leak I mentioned turned out to be the water pump, mechanic found coolant ABOVE the pump on the hose that goes into the throttle body, it seems the pump was leaking and throwing the coolant around. I bought 5 new OEM (Made in America) AC Delco hoses and a new AC Delco professional water pump with a new thermostat and housing. Also had the transmission evacuated, he sucked out all the old fluid (12 qts.) and replaced with new OEM fluid and a conditioner. Took a ride today, trans shifts nice and smooth (always did anyway), only difference I noticed was the DIC coolant temp was higher then with the old thermostat, it averaged 199* to 205* and got as high as 216* at a long light. Cruising it went down to 194* but then came right back up to around 200*. Old readings used to be 192* cruising and never higher then 212* in traffic. No coolant smell and no leaks, I'll watch it for awhile, outside temp ws around 60*. I'm wondering if the old thermo was 186* and the new one is 195*, I'll take the old one out of the old pump and check it. Cars going back in 2 weeks to have a rear end leak repaired and the fluid replaced and have the fuse box recall done...thanks to all for the tips!

 

My bet as well!

If you invest in new hoses, spend the extra and get the silicone ones.