#RadiatorCap

Dave writes:

Hello Sajeev,

I have a 2004 GMC Envoy, 4.2-liter six-cylinder, with about 123k miles that seems to be leaking coolant from somewhere around the radiator cap. Every time I come to a stop with the windows down or pull into the garage I can smell antifreeze. The radiator appears full and the reservoir seems to be maintaining a fairly consistent level of the pink stuff. It never leaks enough that I see wet spots except now and then around the cap, and even then it’s only a few drops at most. I’ve taken it to the mechanic; they double checked all the hoses and connections and even replaced the cap, but it didn’t help.

I replaced the cap a second time thinking I got a bad one, but the smell remains. By happenstance the cap I bought happened to be the exact same brand the mechanic used. I’ve attached a picture of the engine bay showing the areas where I can see dried coolant. The perplexing part to me is that, judging by the splatter pattern near the oil fill and the air filter box, some of the coolant seems to be making it to the fan. Still, I never see any wet spots leading in that direction. Do you have any suggestions?

As a side question, I have been getting an intermittent CEL with an associated P0526 code (fan speed sensor). It will come on for a trip or two and then go away on its own. Any chance the supposed coolant hitting the fan could be causing the CEL?

Newsom writes:

Sajeev,

I am a newbie here so I am not sure that I am posing the question in the correct cyber-manner but here goes: I purchased a 2000 Nissan Frontier 4-door truck new in August of 1999. It has 112K miles and I have just replaced the clutch: it was the training vehicle for my teenage daughter. I have a son who is 13 who will also learn to drive on this vehicle, then it will be put to pasture.

When I took the truck to my mechanic to get the new clutch I told him that I smelled burning coolant when I got out of the truck. He did a pressure test and said it came from the radiator, which he replaced.

I still smell it however and I need help. There is no puddle of coolant under the truck after it has been parked. I replace about 1 quart of coolant about every two months or so but it is not disappearing rapidly. I have been resisting using the words h*** g****t for fear that he will recommend replacing them to the tune of big $$$. The smell is strongest under the hood. I don’t smell it near the tail pipe.

Please help. We cannot live without a truck in the family.