Well a new, but somewhat old problem has re-surfaced with my 300SD. I couple weeks ago i thought i noticed a week coolant smell inside my car after driving for about 25-30 minutes, so i pulled over and looked for any obvious leaks etc, and found none. I did notice that the car was low on coolant however, so later that night i topped it off. That did drop my engine temp a couple degrees (about 81 now, used to be about 85). Today the smell came back after about 15 minutes, and it was worse. When i picked up my girlfriend, i asked her if anything smelled funny as she gave a weird expression when the car started, and she said "yea, what is that". I told her i didnt know, but it probably wasn't good. I then got the "eye" and told her not to worry, we werent gonna get stranded, lol. Anyway, i looked under the hood again tonight, it has lost a little bit of coolant, and there is no puddles anywhere to be seen. If i do have leak somewhere how do i start to look for it? The smell isn't affected by whether i run a/c on full or heat on full, but it is coming in through the air ducts. I can't smell anything under the hood, but i doubt i could smell a small leak anyway, even considering how picky i am. any thoughts appreciated, i plan on just driving it for a while and monitoring my temp guage a little closer at the moment. Temp stays between 80-95 depending on traffic, a/c, time of day etc. In other words, it's not overheating. No coolant in oil, oil in coolant. I am NOT using MB coolant, the radiator was replaced last year, with both the top and bottem radiator hoses( NAPA hoses though.... Nissen radiator)
thanks
Ryan

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83 300SD.......sold
96 integra SE....sold
99 a4 quattro....sold
2001 IS300.......sold
2002 330i.........current.
2004 highlander limited....current.

Looks like you have a minor coolant leak under the hood, and it is evaporating on the motor before it gets a chance to drip on the ground.

Check all the hoses, if all are OK I would replace the water pump, it's an easy job, and about $35.. it can't hurt. It is probably the pump as the bearing is just beginning to fail, soon it will gush out and leave you stranded.

Ryan,
You might also have a leak in the heater core. A leak here will sometimes drain through the AC condensate drains or under the carpet on the passenger side. If you are in the neighborhood sometime you can drop by and borrow my cooling system pressure tester. It makes finding leaks much eaiser.

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Bob D.
Parrish, FL
1 SDL, 1 D, 1 TD, 1 Mog

It is most likely the heater core. A very small leak will not show liquid, it makes a mist which is blown into the cabin producing the smell.

Good luck,

how expensive/hard to replace is the heater core. Where is the heater core in these cars?
thanks
Ryan

__________________
83 300SD.......sold
96 integra SE....sold
99 a4 quattro....sold
2001 IS300.......sold
2002 330i.........current.
2004 highlander limited....current.