First time user here. My wife's 2005 G.C. (99k) is losing antifreeze. It was actually bone dry when I first saw it and I've refilled the overflow more than once but the car still doesn't overheat even on longer trips. Could it be something simple like the radiator cap and how can I visually tell if it's bad? Also, the A/C freon has been recharged a couple times but only lasts 3 or 4 days. A local mechanic threw some dye in the A/C system but couldn't find the leak. He also replaced the water pump (which I assume he actually did) but that didn't solve either problem. I know it's not much detail but COULD these problems be related? The heat works perfect if that's any help. Thank You.

 

No, they are not related. And most common leak on those vans are Rear Evaporator. Which is inside, if it is leaking Freon, it will be hard to see the dye.


As for the coolant leak, you really just have to visually look under the car and see where it is coming from.

 

The only way I can conceive of that these two could be related is if the van was in a hard front-end collision that busted both the A/C condenser and the radiator. Possible, yes. Likely, no.

You can visually check a radiator cap for obvious damage to the metal or to the rubber seals, but you wouldn't be able to check the most important part - the pressure valve - unless you had a special tool. That being said, radiator caps aren't expensive and are easy to replace, so if you don't know how long it's been since you replaced it it wouldn't hurt to do so.

I'm pretty sure you have a leak somewhere in your cooling system. Given the symptoms you described I don't think you have a blown head gasket, but you could have a leaking hose, radiator, heater core, etc. If the leak is small enough then it is possible for you to run the reservoir low but still have enough coolant in the radiator to keep the engine properly cooled and the heater working properly. Like Steak said you would really need to get in/under there and closely inspect each hose and check for drips/leaks. Also check if your carpets are wet for no obvious reason, as this is a symptom of a leaking heater core.

 

First thing this AM I opened the radiator cap. Everything seemed fine and I could see plenty of coolant. I refilled the reservoir and ran the car about 15 minutes. Only thing I saw was a little condensation on the bottom of the reservoir itself. I could see movement of the liquid inside the reservoir but no drips on the outside. Both fans went on and off from time to time. I put some cardboard down underneath and still an hour later don't see any drips on it. I see a small opening in the reservoir that looks like it's an outlet in case the fluid gets too high? Could this be part of the issue? Is too much coolant flowing from the radiator to the reservoir at certain times and coming out of that opening?

 

That opening is there to prevent the system from blowing up if too much coolant escapes to the reservoir. I'm not sure where it is on yours, but on mine it's so high above the MAX line on the reservoir that the only way coolant could get out of it under normal driving conditions is if the reservoir was filled above MAX on a cold engine.

You might want to take a good look at the hoses, as they are sometimes routed above hot components like the exhaust manifold or the transmission. If coolant drips on a hot component it's going to evaporate before dripping on your cardboard. Also if the van has a rear heater check the area under the rear right wheel.

 

If the leak were between the intake manifold and cylinder head would that still leave my radiator full of coolant? I'm having a hard time understanding that the coolant from the reservoir disappears but the radiator is at a perfect level and the car doesn't overheat.

 

***update***
- The A/C leak was the line from the engine to the rear of the vehicle. It was rubbing and over time caused a hole. Nice design, probably could have been avoided. I feel I got raked over the coals with a $630 bill on that one. A line and maybe 2 hours of labor plus freon for $630? Really?
- 3 shops diagnosed the coolant leak at the intake manifold, estimates ranged from $450 to 700. By the time I decided to have the work done shop #3 said the radiator was in full leak mode. Funny how 2 days earlier he didn't even notice it. I replaced that and will monitor the coolant level in the reservoir and will do the intake when it gets a little worse.

 

Did you alrdy Fixed it? if you did, I might have some bad news for you.
I think some 2005 underbody A/C lines are under a Recall.

 

I am the second owner which means I was probably not covered anyway.
Question - if a reputable independent repair shop knew this before he fixed it would he typically tell a customer?

 

Recall is covered by anyone that owns the vehicle, weather 1st owner or 2nd. You just need to know if the recall was ever done. If you don't know what was done, send me a pm with the last 9 of the vin and mileage and I'll be able to let you know.