Smells like coolant
03-19-2015, 08:00 PM
#1
Registered User
Thread Starter
Smells like coolant
Like the topic says I've been having a coolant smell coming from my car ever sense I've change my radiator and fans. I have a Mishimoto 2 layer and slim fan radiator now. Filled the coolant system with new Honda OEM fluid. I've not been able to find any leaks or pooling of the coolant anywhere. The one thing I have noticed is once the car warms up to its normal operating temp the radiator starts to send fluid to the overflow can. Then when it shuts down it somehow sucks it back up because my overflow can levels area always good. Maybe its just me smelling things but should the fluid in the overflow can be that hot to where I can smell it when I get out of my car. Thinking maybe a radiator cap problem??? 
Let me know what your guys think.
Let me know what your guys think.
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Seafoam_green_s2k (08-31-2019)
03-19-2015, 08:17 PM
#2
the level in the over flow tank should rise as the car warms up and drop as the temp goes down so that's normal. u might just be smelling a little coolant residue or something. if you over fill the coolant overflow when the car is cold when the car warms up it will overflow out the tank could be smelling this
03-19-2015, 08:24 PM
#3
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Thread Starter
the level in the over flow tank should rise as the car warms up and drop as the temp goes down so that's normal. u might just be smelling a little coolant residue or something. if you over fill the coolant overflow when the car is cold when the car warms up it will overflow out the tank could be smelling this
I would say its a possible residue but this is about 6 months and 500 miles later I'm still getting the smell. Everything is working right it goes up on warm up and sucks it back up on cool down. When the engine is at normally temp and a hour drive the coolant is never above the full line on the overflow. So this has left me scratching my head
. Unless I have a super small leak somewhere only under pressure. I've yet to be able to find any powder rez left from dried up coolant. Is it possible that the new coolant gives off a more dominant smell in the over flow just because its new?
03-20-2015, 01:32 PM
#6
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Thread Starter
The temp seams fine. Runs at the normal AP1 3 bar. I've not logged anything with AEM may do that this weekend to see actual temps. Heater core possibly? hmmm seams like she will be going on stands this weekend and ill lay under her searching.
03-20-2015, 03:28 PM
#7
I hope that I don't confuse you with my reply, but I have been going through this for a long time.
My car has smelled like coolant for many, many, months and it would always bug me. I had changed the radiator a couple of times, and I changed all of the coolant hoses (big and small) in the past, along with regular coolant changes. I also did multiple cooling system bleeds. All of these procedures have caused fluid to spill in the engine bay. I could never find any leaks, and the water pump was not weeping coolant from what I could tell. It always smelled like coolant after the engine got hot, I could often smell it from outside of the vehicle. Some people recommended that I powerwash the engine bay to get rid of coolant traces, but I never got around to doing that.
I always thought the smell got stronger as the radiator fluid dumped into the oem overflow tank. The lid on the oem tank is fairly loose, so it can release odours if the fluid is really hot. With an aftermarket radiator and higher pressure rad cap the radiator will dump into the coolant tank at higher temperatures compared to the oem setup. Higher pressure means the fluid heats up to a higher level before being dumped into the coolant tank.
I went over all of the hose clamps to make sure they were all snug and the clamps were positioned at the right locations on the metal connectors/ pipes. I found some of the smaller hoses around the throttle body weren't overly tight, and the metal connector pipe around the idle air control valve had a bit of rust on the surfaces that connected to the smaller hoses. I took it apart and cleaned it up, and I put the hoses back on with new Honda clamps, just as a precaution.
I recently installed a Knight metal overflow tank that I bought from Moddiction. So far after driving the car a few times this spring the smell of coolant is almost non-existent, it seems like a big improvement.
The new overflow tank may be releasing less odours, overflow tanks can't be air-tight due to the way that they operate, but the new tank may be releasing less odours.
I don't know if this helps but that is just my experience thus far on the same issue.
My car has smelled like coolant for many, many, months and it would always bug me. I had changed the radiator a couple of times, and I changed all of the coolant hoses (big and small) in the past, along with regular coolant changes. I also did multiple cooling system bleeds. All of these procedures have caused fluid to spill in the engine bay. I could never find any leaks, and the water pump was not weeping coolant from what I could tell. It always smelled like coolant after the engine got hot, I could often smell it from outside of the vehicle. Some people recommended that I powerwash the engine bay to get rid of coolant traces, but I never got around to doing that.
I always thought the smell got stronger as the radiator fluid dumped into the oem overflow tank. The lid on the oem tank is fairly loose, so it can release odours if the fluid is really hot. With an aftermarket radiator and higher pressure rad cap the radiator will dump into the coolant tank at higher temperatures compared to the oem setup. Higher pressure means the fluid heats up to a higher level before being dumped into the coolant tank.
I went over all of the hose clamps to make sure they were all snug and the clamps were positioned at the right locations on the metal connectors/ pipes. I found some of the smaller hoses around the throttle body weren't overly tight, and the metal connector pipe around the idle air control valve had a bit of rust on the surfaces that connected to the smaller hoses. I took it apart and cleaned it up, and I put the hoses back on with new Honda clamps, just as a precaution.
I recently installed a Knight metal overflow tank that I bought from Moddiction. So far after driving the car a few times this spring the smell of coolant is almost non-existent, it seems like a big improvement.
The new overflow tank may be releasing less odours, overflow tanks can't be air-tight due to the way that they operate, but the new tank may be releasing less odours.
I don't know if this helps but that is just my experience thus far on the same issue.
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03-20-2015, 04:12 PM
#8
As J noted aftermarket radiator are capable of higher pressures (welded instead of brazed). As such after market radiator caps can vent at a higher pressure. Check whatever cap you have now vs. the OEM relief pressure. Increased vapor pressure, now of the overall cooling system, greatly improves thermal dissipation. This due to higher temp fluid being exposed to a greater surface area of radiator (core thickness, number of core passes, etc.). The overflow can is essentially an expansion chamber as J said. So we now have much hotter fluid venting into the unsealed expansion chamber. If you examine the plastic "fill plug" where the hose connects back to the filler neck of the radiator you will find you can unscrew the cap and the hose stays in one direction. This is the joint that leaks and releases the smell. Take a whiff. The loss is extremely minimal but the smell can be strong. When the car cools a vacuum is formed and the coolant gets sucked back into the closed cooling system. Note the overflow tank hose back to the radiator is below the fluid level (or should be ) in the overflow tank. So under vacuum created by cooling fluid is sucked from the base of the tank.
Utah
P.S. J- the reason aftermarket aluminum tanks smell less is you now have a welded immobile fitting on the overflow tank back to the radiator; and a much better tank cap seal (I.e. Rubber)
Utah
P.S. J- the reason aftermarket aluminum tanks smell less is you now have a welded immobile fitting on the overflow tank back to the radiator; and a much better tank cap seal (I.e. Rubber)
03-20-2015, 05:14 PM
#9
As J noted aftermarket radiator are capable of higher pressures (welded instead of brazed). As such after market radiator caps can vent at a higher pressure. Check whatever cap you have now vs. the OEM relief pressure. Increased vapor pressure, now of the overall cooling system, greatly improves thermal dissipation. This due to higher temp fluid being exposed to a greater surface area of radiator (core thickness, number of core passes, etc.). The overflow can is essentially an expansion chamber as J said. So we now have much hotter fluid venting into the unsealed expansion chamber. If you examine the plastic "fill plug" where the hose connects back to the filler neck of the radiator you will find you can unscrew the cap and the hose stays in one direction. This is the joint that leaks and releases the smell. Take a whiff. The loss is extremely minimal but the smell can be strong. When the car cools a vacuum is formed and the coolant gets sucked back into the closed cooling system. Note the overflow tank hose back to the radiator is below the fluid level (or should be ) in the overflow tank. So under vacuum created by cooling fluid is sucked from the base of the tank.
Utah
P.S. J- the reason aftermarket aluminum tanks smell less is you now have a welded immobile fitting on the overflow tank back to the radiator; and a much better tank cap seal (I.e. Rubber)
Utah
P.S. J- the reason aftermarket aluminum tanks smell less is you now have a welded immobile fitting on the overflow tank back to the radiator; and a much better tank cap seal (I.e. Rubber)
03-21-2015, 11:10 AM
#10
Registered User
Thread Starter
Thanks for the insight J and Utah. Think ill do one last good leak check tomorrow and then let her be if i find nothing. Just have to start walking