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04 s350 smokes under bonnet upon starting?

1K views 7 replies 4 participants last post by  636CBR 
#1 ·
Hi everyone: I have an 04 S350. Today when I started the car, white smokes started to come from under bonnet passenger side (not burning smell but smelled strange) with hissing noise (similar to noise from suspension) ! No malfunction however was indicated from screen and the engine temp was normal (~80-90c). However the ext. temp showed -38c (negative 38 degree celcius)! I quickly turned the car off and the smoking stopped. When it was re-started, no more smoke but the ext temp still showed negative temp. After 15 minutes of driving (nothing seemed unusual otherwise ), the ext temp returned to ~22c (normal). It hasn't happened again since. The air con is still working fine! Should I get it checked out? any ideas? Thanks
 
#2 ·
You should have someone check that out! Does it smell like wires burning or possible anti-freeze? You said not a burning smell as in OIL? Anti-freeze will give you a very unusual smell, maybe a small hole in hose or gasket somewhere? If it was a A-F leak you would have it all the time. have you checked you A-F level? what you explain with temp sounds like maybe a fried wire that could still have contact. i.e. burnt case. But for sure have it checked. do not wait until it becomes more serious.
 
#4 ·
Thankyou everyone for your advice. I better check out what my A-F level is firstly. The strange thing is it only happened once (Smoke or maybe steam + negative ext temp). Since then the car runs fine without any anormalies; even my ext. temp gauge functions orderly ! Still no malfunction was ever indicated ! My computer detection should still work as around X'mas, it showed malfunction as one of me fog lamp was gone, and I checked that it was. However 1 week later the bulb came alive again before I had he chance to change it and the malfunction signal subsided then.
I did a thorough search and it doesn't seem like anyone has had this smoke/steam problem before so I think I'll take it to the dealer to have a look and I'll keep you all posted.
 
#8 ·
The answer from the dealer was that there was a leak in one of the engine gasket, and another leak in the "tappet?!". Don't know about the negative temp. So a new gasket needed but aroung the tappet can only be re-sealed as otherwise a new tappet is needed.
Thanks everyone!
 
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