Engine Coolant Odor Present

G

GTCX9WantOneBAD

Member
I have an 08 GT CX-9 with 2,200 miles on it. I recently starting noticing engine coolant odor coming from under the hood when the car is running at normal operating temp according to the Temp Gauge (at normal ops temp it reads slightly to the bottom half of the halfway hash mark). In my experience with cars, I've never smelled coolant odor unless the car was overheating. However, I've never seen the temp gauge go above the halfway hash mark. This leads me to suspect that either the gauge is giving me a false reading or my Radiator Cap pressure spring is weaker than it's suppose to be and allowing coolant to overflow into the coolant overflow container. Has anyone had any experience with their CX-9 and smelling radiator coolant coming from under the Hood?

Thanks in advance....
 
Actually I have noticed this as well. When I pick up mail from community mailbox area I can smell it and occasionally after parking in garage shorlty after. I have looked for leaks and found none. Nor have I seen any drippings. I do believe the temp is normal as well as both gauge and engine compartment seem normal. Perhaps the overflow bottle is not well sealed.
 
Thanks for the reply. Yes, it is the job of the anti-freeze overflow container to catch boil overs...however, in my experience, the engine should never boil over into the overflow unless it is overheating or the radiator cap is faulty. In other cars you never smell it until they overheat and overflow into the container.

Does anyone else have this problem?
 
YES--I have noticed this too, especially after I park it in my garage.

I have an appointment for a LOF Thursday, and I'm going to mention this. Plus the grinding sound I'm getting from my brakes.
 
Thanks for the MSB...my VIN is not listed in the range, but I will still check the tank lot number to see if it matches any on the MSB list.

Thanks....
 
Force-1 said:
YES--I have noticed this too, especially after I park it in my garage.

I have an appointment for a LOF Thursday, and I'm going to mention this. Plus the grinding sound I'm getting from my brakes.
Click to expand...

Got my CX-9 back from the dealer. They did a full coolant leak and pressure test--no leaks. They called Mazda and were told this coolant smell is normal since so much plastic, aluminum, etc., is used in the engine area.

They also ordered me new brake pads to try and fix the grinding sound I'm getting. Apparently others have complained about this, so there's a TSB on it.
 
coolant odor present

Hi all,

Hope this gets to you after you've gotten your CX9 to "not" continue to offer up that smell. I have a 2008 AWD GT and it has for a year now continued to smell from time to time (almost random) and the dealer -after three specific visits did not find or fix the problem. They state the last time that the problem was a lower radiator hose and added a clamp, yes, it still is doing the odor thing.

it is a rediculous problem, Friday of this week, i am going in there to give them a copy of comments from this page and get them to pressure test and replace that tank. It makes sense that it is coming from the coolant tank/reserve. The tank is suppose to allow expansion and contraction of fluid from the radiator on a continual basis. The engine rpm primarily dictates it when the water pump is speeding up and slowing down all the time, based on throttle imputs. If you've ever had the cap off and hit the throttle, the rush of fluid is forced through the engine block. (I have noticed this mostly from experience with my race car when breaking in a new engine.) So, the reserve tank is filling and draining whenever the pressured radiator cap opens and closes.

The excuse of "plastic and other materials around the engine" is pure crap, there is no reason for it to happen other than a faulty design. I strongly believe that the radiator reserve tank is the culprit, especially when the dealer pressure tests the whole system without testing the reserve tank separately. I think a series of 2007 tanks were put into the 2008 lot on the beginning of that run (I could be wrong)

Please respond back if anyone has found the culprit and if my rant here is correct.

thanks,

DSherwood
 
DSherwood:
The coolant tank(also known as a degas bottle) is part of the main cooling system and is pressure tested at the same time,as the rad cap is on the coolant tank.There is not a separate recovery tank.I work at a Ford dealership(my wife won the CX-9).We add a floresent coolant dye,have the customer drive the vehicle for a month or 2 and then check for coolant leaks using a black light.Hopefully your dealership has access to this method.

bronco1
 
thanks Bronco1, I spoke with the general manager and the service manager today, i am just tired of the car's odor. I just want it fixed. I'll ask them about the dye, it makes perfect sense. I thought they might have just put the pressure tester on the rad cap, thus removing the coolant tank from the system. thanks for giving me accurate data.

anybody gets theirs fixed, please pass it on, this is very annoying on such a great overall car.
 
got my car back from the mazda shop, when I got there, I put up the hood, the service manager came out and I took my finger and reached under the lower coolant hose to the overflow tank, and sure enough there was fluid on the bottom of it, end of story. Yes, mine is a 2008, and they pressure tested it at previous trips and wow amazing, no smell on the way home from installing a new tank! I have everyone to thank for responding to this as I printed it out, left the documentation on the dash for them to read (don't know if they did or not) the main point is, I got resolve and definitely know it smells like leather in the car, not a sweet hint of antifreeze. Now if we could get a blizzard to try out these new blizzak winter tires. Anyone using stock tires in ice conditions, well they deserve three season traction.

Thanks again,

DSherwood
 
Well, to no avail, the problem is still there, new coolant tank, pressure tested cap and it is coming out because the pressure is more than the 16 psi cap. the 48 hours of no smell was good, and back to mazda we go.

What would cause it besides something pressurizing the system beyond the norm (doubtful its a head gasket)

Bronco1, please if you have any suggestions, I'd certainly be happy to hear back.

DS
 
Any suggestions as to why the pressure is too great for the cap, they replaced the tank and sealed that up, it is something to do with the overall closed system, it pushes fluid out, when I slow down (25-30mph) the cabin fills with the smell of coolant. We know it is coming out the short hose at the pressure cap.
 
First off,make sure the cooling system is not over filled hot,then proceed to step 1.(1) An air line pressure regulator and an accurate pressure gauge should be tapped into the cooling system.(2)The cooling system should then be pressurized slowly until the rad cap bleeds off pressure and note what the release pressure of the cap is.If it is lower than the specifications for the cap,then replace the cap and recheck,once this is ok then continue on with step 3.If there is leakage between the cap and the degas bottle,then lightly sand the sealing surface smooth and recheck,if it still leaks under the cap,then replace the cap-once any leakage from under the cap is stopped,then proceed to step 3.(3)If the cap is with-in specification or has been replaced,remove the pressure regulator and leave the pressure gauge hooked up and go for a road test.If the pressure exceeds the release pressure of the rad cap,the cooling fan operation needs to be checked,if this is ok then proceed to step 4.(4)Check the cooling system for the presence of combustion gases with a cooling system combustion gas tester.I don't know if Mazda has a tech hotline for the tech's to contact,but if they do,they should be contacting them for some additional factory engineer assistance.This is the proceedure that i would use in trying to find the cause of the coolant loss.Of course this would be after dye had been added to the cooling system and the vehicle driven until the coolant smell was evident and a black light was used to determine that the coolant was leaking from the cap vent hose.

Good luck; bronco1
 
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could it be as simple as the fans are not coming on when slow in traffic? I never hear them come on.

Have appt on Monday, oh so tired of this.
thanks Bronco1,

It amazes me that people are willing (on here) to offer realistic advice when the troubleshooters should be the ones at the dealer. They have been acting like their doing me a great favor.

DS
 
it looks like the dealer has fixed the car, they kept it for four days, pressure tested it from dusk to dawn and it went down from 20 or so to 6 pounds. It ended up being the upper radiator hose, replaced it with a real clamp. I drove a new acadia, wow a good vehicle but felt like a tahoe and couldn't wait to get back in the '9. I sure missed the personality that the mazda has. nothing bad on the gmc, just lacking when compared to how the mazda feels.

DS
 
what is your vin, i am almost positive yoru vehicle is covered under the coolant sub tank recall, you should of had them check for open recalls first
 
Boy I wish that was it, they already replaced it, this one has Mazda stumped at the moment.

No sign of coolant loss, it did leak at the sub tank, but no more, now just when the speed is right (relatively slow, traffic...)the odor is drawn into the fresh air by the w-shield, or if I have the window open, hit the recirculate, the odor goes away. Or if it has leaked when in the garage and upon start up the odor is present. Love the car, great in the snow (with real winter tires) and fun to toss around on curves, former mazda racer here.

thanks for the reponse.

D
 
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