i changed my radiator to a mishimoto aluminum and samco silicon upper and lower radiator hoses. I bled the system and no bubbles. I always get a coolant smell everytime i drive the car. I have pressure tested the system and can no find any leaks. I have not had to top off the coolant in the past 6 months. I have hosed down the engine bay around the radiator and thermostat ends. Can not see any residue for left over or leaking coolant.

reason why i changed the radiator was cause my car has 140k and last track day i saw the gauge go up to 3/4ths and withing half a lap of cool down it went back to normal. it was not leaking or anything just that i figure its about time as i think the original one may crack soon. i did the hoses cause i was there. i reused the oem spring clamps and no leaks from the ends. Sensors and drain plug have no leaks as well.

 

I've had the same issue for about 2 seasons now, whenever I drive my car I get a coolant smell from under hood. I don't get the smell from the exhaust, and there are no leaks on my garage floor. My coolant level is pretty steady. All of my hoses are dry, my sensors are dry, manifold is dry, and radiator is dry, water pump dry. I don't have any engine coolant showing up in used oil analysis tests of my engine oil.

I first changed to a Mishimoto radiator and Samco hoses. Later on I got a killer deal on a Spoon radiator and I decided to swap it in place of the Mishimoto as the Spoon rad was a tad thinner and a better fitment with the oem air box.

With the rad and hose swaps I did dump a lot of fluid within the engine bay. I never washed the engine bay so I chocked up the smell as being from the coolant that spilled in the bay, and it becomes evident when the engine gets hot.

My only other suspicion is the Mishimoto radiator cap that I'm using. I don't know if it lets off pressure when I'm driving and if that causes the smell. It's the only part that has been consistent between the two radiators. I've actually got a Spoon radiator cap on order to see if maybe my cap has been causing the smells ?. I'm hoping to test it out this spring.

Mishimoto radiators are pretty decent pieces, but I know that they've had many issues with their radiator caps leaking. What radiator cap are you using ?.

 

The cap area is bone dry which kind of sucks cause i would think it's not leaking.

I was wondering if it's the samco hoses being slightly permeable which would allow coolant to soak into them

 

I've always wondered if the new rad is dumping fluid into the expansion tank at higher temps, since it operates under higher pressure. The odour of the hotter fluid may be more noticeable. The expansion tank isn't air-tight, when the aftermarket rads dump fluid it is at a higher temp due to operating pressure differences compared to oem rads. Just a guess

 

But you would think you would be able to see the difference in volume of the tank. Simple test would be to empty the tank and see if anything goes in

 

The hot volume of the overflow tank will be higher than the cold volume, the radiator will dump fluid into the tank on most trips, and then suck it back into the rad upon cooling.

The higher pressure rad cap opens later, so the fluid going into the overflow tank is hotter and under higher pressure compared to lower pressure rad caps like oem.

 

I think it's your silicone hoses that might be the cause, they have a much higher water permeation rate than rubber hoses.
This means you will lose coolant through the walls of the hoses over time.

http://www.youtube.com/watch?v=rSl0URba_ho

No I don't work for Gates

 

I thought it might be related