Tracking down coolant smell up front (and very slow loss)

I've been hunting coolant smells since first bought the car but even when it happens I never see much loss of coolant. I have to add like 16 oz of water maybe once every 2 or 3 months to keep the line above <min>. About a year ago my AOS blew out and the car dumped coolant everywhere. I figured that was the end of it and that was where the smell was coming from. Well it seems that randomly I'll still get that antifreeze smell (sometimes stronger than others) coming from the driver's side front wheel well. When it happens there is ZERO smell coming from the engine compartment. I removed my bumper cover and cleaned out the radiators but didn't see any clear evidence of a leak. I did see what looked like very slight corrosion around the top seam of both radiators but it is difficult to tell if it is coolant. All lines to and from both radiators look dry as a bone. I tried Macster's poor man's pressure test and while I didn't get any leaks at all, I swear if I got close enough I could smell coolant on both radiators. I really don't want to spend $800 on two new radiators when I'm not 100% sure they are leaking but I don't know what else to do. I could pay a shop to do an extended pressure test but risk wasting money for them to tell me either a) it holds pressure and they can't find anything or b) it has a very slight loss of pressure but we aren't sure where it is coming from. I'm tempted to try the dye in the coolant trick, but if it is only vapor that is escaping through the top of the radiators, would the dye even show up? Any other places to look up front? I'd rather not wait until it is a full blown leak because I'd like to get my wife on the track with this car and don't want it to happen while she is in the middle of a session.

FWIW - it seems you have done the most prudent things to do so far. However, given the "coolant smell" and loss of coolant over time, I would opt for the dye. Even with a vapor leak it will show up under the UV light. Then you will know for sure where your leak is and can plan accordingly.

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I could pay a shop to do an extended pressure test <<<<<<< +996 to this

I'd go the UV dye route first.

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Ugh I guess you are right but they already did that after replacing the AOS. I guess it is possible something has popped since then. My other worry is that they will sort of expect to get the work after the diagnosis and I'd prefer to do the work myself.

Betcha the leak is from the top seams of the radiators. Just replaced all 3 radiators in my 996 Turbo and the bottom seams were leaking. FYI, the leak doesn't have to be very big or even that obvious. My 1996 Mustang GT radiator developed a leak. Walked out to the car in a SLC hotel parking lot one morning and spotted a small puddle of coolant under the car. Well, the fact there was a leak was obvious, but where the leak was coming from was not. Long story short the local Ford dealer tech found the leak. Lucky for him and me it was a pinhole on the back side (engine side) of the radiator. The pinhole was dry, but there was a slight stain down the radiator from where the pinhole was suspected of being.

I think you are right. I just don't see any other place where it would be coming from. I now even recall times where I opened the frunk and got a whiff. I guess its time to replace them but I did have one question. Are there any negative effects of using the dye?

^^^ NO

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My 2nd hand info is the dye is harmless. (There are florescent dyes for engine oil leaks, A/C leaks, and cooling system leaks. My 1996 Mustang had the engine oil dye used to highlight an engine oil leak. Oh, the dye glows when a black light is used to "illuminate" the leak area.) A whiff of anti-freeze odor is a sign of a leak. When I caught a whiff of anti-freeze odor at the driver's side door of my 996 Turbo I immediately took the car over to the dealer and managed to get it on the lift for an inspection and the tech spotted signs of the water pump seal leaking. It had been leaking a while as there was the build up of anti-freeze residue. Might mention early in Jan. this year the Turbo's radiators were found to be leaking. Actually, I had spotted what was or had to be coolant puddles at each front corner of the car but believed the puddles were water from snow that had melted from the heat of the radiators. The car was outside at the hotel in mid-Missouri over a week or so of very cold temperatures -- down in the single digits -- and blowing snow and in the morning before heading out I'd spot some of this snow in the radiator ducts. Even though all 3 radiators were leaking and of course the puddles were coolant, I never smelled anti-freeze. Too damn cold, I guess. A few years prior I'd catch a whiff of antifreeze from the Boxster, around the rear of the car, sometimes after opening the rear trunk. At some point when the coolant level got low I id'd the cap as the leak source and replaced it. But still every once in a great while I'd catch a whiff of anti-freeze odor. Finally I did my (infamous?) hot pressure test and the coolant tank finally manifested the unmistakeable signs of leak. After the tank was replaced no more anti-freeze odor. This no odor of anti-freeze is not my imagination. The Porsche techs tell me with the older cars, our cars, one shouldn't smell anti-freeze. If you do there's a leak. With the newer cars that may not be the case. The difference in volume between the min fill mark and the max fill mark is so small now if the coolant level isn't just "so" the engines can somehow expel a bit of coolant at times -- through some overflow or pressure relief valve -- and the techs say sometimes one can catch a whiff of anti-freeze but the cooling system does not have a leak. And because the engine can expel a bit of coolant once in a while the coolant level has to be watched a bit closer. But avoid overfilling or the thing will just expel this excess coolant and there'll be the smell of anti-freeze or one will observe the level is down again and add more coolant and repeat...

Most auto parts stores have loaner pressure testers. Worst case just pay a shop for their labor to pressure test the system, then you can repair it.

Great, now I'm paranoid.

Nothing to be paranoid about really. My car has been amazing and even when the AOS blew and coolant went everywhere the car was fine. Some of our cars are just getting older and need a little TLC. Any other car would too. Plus, changing radiators (and even the water pump) isn't too difficult.

Done water pump already. Thought I got a whiff at driver front the other day. No coolant loss though.

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Well, that's a sign there is a leak. Monitoring coolant level on these cars can be a bit tricky. I hate to admit but I got fooled into thinking the level was ok when in fact I was just seeing the stain of the coolant on the tank. I tried to jiggle the car a bit, up and down a bit, to see if the coolant level line moved and I thought it did but in hindsight I think I was just not paying that close attention. I wanted the level to be ok so that is what I saw. Only when the warning light came on and I bothered to unscrew the cap -- after the engine had cooled down -- and removed the screen and peered down in the tank through the opening did I realize how low the level was and how stained the inside of the tank was and how I had been "fooled" by the stain into thinking the coolant level was ok. How do the radiator ducts look? Have you been keeping these clean of trash/litter?

Definitely use dye + yellow goggle + blacklight and remove the front bumper so you can visually check the radiators. I've used the traceline leak detection kit ($50 or so and it includes the light and goggle) and it works like a charm.

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This^^ http://www.nationaltoolwarehouse.com...FZMkgQodJ2cAUw

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Oh yeah, that's the exact kit I used.

I was about to start a new tread when I came across this, I also have the same problem, I can smell it only sometimes, but is not leaking anywhere. My temperature stays between 182' - 194' according to the electronic temperature Scan tool. I also noticed lately my fan is not coming on like it used to. Last month I checked the antifreeze for the 1st time since I got the car (8 months ago) and the antifreeze was low, it almost took a � of a gallon of antifreeze to fill it up. Any thoughts on this?

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Normally with a drop in coolant level I'd advise you to replace the coolant cap unless of course it is new. But with the smell of anti-freeze there's almost certainly a leak. I would still advise you to if the cap is original or has an old part number to replace the cap. But you need to get the car in the air and check for coolant leaks. If no leak sign is spotted you might have to have the system system pressurized and checked. Sometimes this pressurization works, other times it doesn't. It depends upon the characteristics of the leak. If the leak is via the water pump seal being this is under water (so to speak) and cold the air pressure may not be enough to cause this seal to leak. The same can be true for a small (aka pinhole) leak in one of the radiators. Get the car in the air. Help yourself and the tech by if possible having the car fully up to temperature -- do not have the AC system on to avoid having the radiator fans running all the time -- so the car is in the air with the cooling system at operating temperature and pressure and from the heat load in the engine this works to raise even more the temperature and pressure of the coolant which often helps one spot a leak he might not otherwise spot. At the same time the tech can check the radiator fans to see if they are functioning ok. They can outright quit working. This can be often is due to an electrical problem (a resister fails). The problem can be mechanical: In at least one case I know of, one of my cars, a radiator fan motor shaft snapped. In another case the fan was spinning but didn't work very well and the tech observed the fan motor drawing way more current that its counterpart on the other side of the car.

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Awesome thank you for the quick response, as a matter a fact yes the coolant cap is original, that will be on my list to replace. Also is 182'(open hwy) -196'(traffic) normal temp?

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Replace the cap but keep in mind there are always two problems, unless there is just one or 3 or more. The cap can be leaking. The original (at least older original cap) is notorious for letting vapor escape to the point the coolant level drops low enough the low coolant level warning comes on and one discovers it can take nearly a gallon of fluid to bring the level back. I have replaced the cap on both my Boxster and Turbo. Both caps were leaking. But I never smelled anti-freeze. The only times I have smelled anti-freeze and just a whiff or two of the odor -- have been times there was a leak. In the case of the Boxster it proved to be a leaking coolant tank that would only seep coolant when the car was parked with the engine fully up to temperature. As the car sat the heat load would increase and this would force a bit of coolant out of the tank split. The smell of anti-freeze was only present shortly after the car was parked. Many a time I parked the car -- still do -- hot and walk away and then do not return to the car until it has cooled down. There would no smell then. This coupled with the intermittent aspect of the leak due to the variability of the temperature of the coolant and engine heat load when I parked the car had me thinking I was imagining the leak (or hoping there was no leak) -- in spite of my understanding that if there is an odor of anti-freeze there is a leak -- until the tank finally let go with a gush of hot coolant when I did my shade tree cooling system pressure test. In the case of the Turbo the anti-freeze odor proved to be from a leaking water pump. Again I caught a whiff of anti-freeze odor when the engine was quite warm having been driven at a walking pace around a large parking lot then the engine shut off while I got out of the car to help my mother into the car. Replace the cap. But get the car inspected to find the leak that almost certainly exists. Oh, the temperature. What temperature the engine coolant settles at is dependent upon many things, to name a few of the biggies: ambient temperature; how the car is being used/driven; whether or not the A/C system is on. With my Boxster over the years I have observed a steady coolant temperature anywhere from 180F to 226F. 180F driving at 75mph in blistering cold. And 226F driving at 75mph in blazing heat (116F) with the A/C on, or off believe it or not when the A/C stopped working due I guess the extremely high ambient temperature. Even on milder days, I have observed the coolant temperature reach 226F when pushing the car hard in the mountain twisties. And under less extreme climatic and operating conditions at just about any temperature in between the low and high temperatures I listed above. Many is the times that on a mild day (mild enough to not require the A/C) I have heard/felt the Boxster radiator fans come on signaling -- based on experience from previously monitoring the coolant temperature in real time -- the coolant temperature had reached 212F. Based on my experience, and what I was told was straight from the factory when I put in a query about this coolant temperature business once before, is that as long as the coolant level remains good (the level doesn't drop over time), that one doesn't smell anti-freeze, and obviously doesn't see any leak sign nor find any leak sign inspecting the car on a lift, and if the low or overheating or engine compartment fan warning lights stay dark, the cooling system is fine.

The heater core can also be a source of "smells like coolant but doesn't seem to be leaking."

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Yes, the heater core can leak and a number of other things not mentioned. When a coolant leak is suspected the entire cooling system has to be suspect. Having a pro inspect the car is the best course of action as he will check *everywhere*. I would recommend this unless the leak is obvious and after repairs no further leak symptoms are present.

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Awesome once again thank you fot your help!!!!!