Slight smell of Coolant

2012 Base with 90,000 miles Just noticed a slight smell of coolant (intermittent). Checked level and it is a bit low, but don't know how low or for how long. I'm going to top up and start keeping track. Will probably replace the cap just to take that out of the equation. Anyone have any input on common locations for small leaks?

The water pump would be my first thought. Sent from my SM-S908U using Tapatalk

Thanks. Any recommendation metal vs. composite impeller? I will be adding UV dye when I top up.

Same issue here on my 987.2 . First thing to check is the coolant cap (by the engine), but that's more of an issue for 987.1 (that don't have the cap that ends in 04). $30 replacement. Last month, I did a cold pressure test (rented a pressure tester from my FLAPS for free) and confirmed a leak somewhere per the pressure drop. Still can't find it, but it'll show up. If you're not seeing pooling on the floor, or crusts of dried coolant anywhere, what may be happening is a very small leak -- that hits your hot engine -- and evaporates before it hits the ground. I bet that's where the leak is (not in the front of the car). Finally, you can do a powder test (spray affected areas with spray baby powder) and see what leaks. Cheering you on; let us know how you get on with this.

Regarding impellers, I would stay with OEM. I have read about the dreaded "impeller pieces can break and plug cooling channels" cautionary tales and although that could happen, the material is quite robust, I trust it. I replaced a Ford Escape pump with a composite impeller last year at 80K preventative maintenance, it was perfect, not so much as a scratch on the impeller or any imperfection.

After chasing a fuel leak on my diesel for month, I am now a believer in UV dye. Just ordered some of the Water based kind (I have oil based for the fuel) I am also thinking composite, just one less metal to add to the galvanic mix.

I replaced my water pump prophylactically at my 60k service (and belt and idler) - no leaks, and appeared in perfect condition (smooth bearings, no play, no erosion) with a Geba from FCPEuro .. which has a metal impeller. Galvanic action wasn't a big concern since the impeller is aluminum as is most of the cooling system. The shaft is steel - but so are the composite pump shafts. I based my choice on recommendations from several Porsche mechanics. It wasn't the cheapest by any means, but it came with a new belt-pully made from steel (the original is plastic). There is a concern with the pre-09 engines ( 987.1 cars) that if the bearing fails and the shaft starts moving around a metal impeller can grind out a pocket in the block where it mounts making a replacement pump much less efficient. That is NOT a concern on the '09 and newer engines - the pump mounts to a replaceable plate bolted to the engine. I will say it was hard to tell (had to scrape it with a knife) if the OE impeller was black anodized aluminum or molded plastic - it felt like aluminum, but scraping an edge with a knife revealed it's high-density plastic. I don't think the factory pump is ever going to lose an impeller. As usual - YMMV - and I don't know which one I'd choose today if I needed another.

just a observation, but if you are smelling it, then it's likely or maybe more likely that the leak is in front rather than behind you. I would look at the front radiators and the hoses.

Well, if the weekend is good, I might get it into my shop and start looking with the blacklight. I figure with the dye in for a week, it is time to start looking.

Another possibility is a leak at the rubber hose that leads to the metal tube running to the front of the car from the water pump housing. It has been known to leak at the joint. If significant, there will coolant on the garage floor under the car behind the driver door in front of the rear axle. Removal of the under panel will reveal the hose.

Also check the expansion tank. They are notorious for cracking at the seam, but not obviously. Coolant stains are the giveaway

No drips and have not noticed the smell the last few days. Guessing it is a very small leak. UV dye is my friend.

Hello Don. I am trying to decide between Porsche (composite impeller) vs Geba (metal impeller) water pumps for my 987.2 . I found a website for Geba and they say the impeller is cast iron. Does this change your thoughts on this at all? As you say the shaft is steel anyway.

Thanks for the quick response Don. I went with the Geba. LN Engineering use the Geba in their 987.2 / 997.2 water pump kit which is also a good sign.