I have a 1992 300 TE that develops a whistle sound (like a teapot) when the engine warms up to 80C. The waterpump has been ruled out as it was recently replaced. The whistle sound does not increase with acceleration. Any hints?

It could be a vaccum leak or a seal that is squeaking.

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Benzmac:
Donnie Drummonds
1992 500E (very soon I hope
1981 280GE SWB
ASE CERTIFIED MASTER AUTO TECHNICIAN
SERVICE MANAGER FOR 14 BAY FACILITY
MERCEDES SPECIALIST 8 YRS
PARTNER IN MERCEDESSHOP.COM

Could it be a leaking radiator cap?

Thanks for responding. I have checked the radiator cap, but the sound appears to emit from somewhere near the front right side of the engine. I thought it might be a vacuum leak, but this confused me why it wasn't making the noise all the time. The noise is emitted when the negine tep reaches 80C. Can vacuum leaks become more prominent with pressure or is the sound more likely from a seal that would certainly be pressure sensitive?

Possibly a vacuum leak from a temp controlled valve. Look around the thermostat housing for a "tree" of vacuum lines and connections. That might explain why it only whistles after reaching operating temp.

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Mike Tangas
73 280 SEL 4.5

check the small breather hose on side of
valve cover,about the size of your index finger,they split down the side.
p/n 103 094 00 82-- only a few bucks.


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Michael Haven CMAT,CMM,L1
MPH Automotive Services
16510 Park Row
Houston, Texas, 77084
281-579-8885

The whistling teapot sound has gone away, YEA! Why?, I have no idea. I brought the car back to my independent mechanic, we reviewed the comments from everyone, looked around for the noise for about an hour and continued to scratch our heads. I made an appointment to bring the car back in within the next week with the plan to take it apart. The noise had been present for over a month and I drove the car everyday. Then two days before the scheduled appoitment the noise completely disappeared! I can only guess that it was a seal that eventually sealed itself up. It's either that explanation or the fact that it overheard my wife that if the car didn't improve she was determined to sell it.

It might be worth checking your intake manifold bolts.
Harvey