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Discussion Starter #1
Hi all. Ive read about the 1975 cat converters in the engine compartment causing vapor lock but is it really a problem? How much trouble / expense is it to have it relocated? Anyone done this?
 

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450slc5.0cab 280sl5sp 280se4.5 500se+500slAMG +250seStkW108 350sl4spdX3 500secEuro
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You would need to replace the exhaust manifolds. If you don’t already have them, assume you’d be in for a $500-$2000 expense since you probably need to modify the down pipes too.

If you don’t mind vapor lock, you might be fine leaving it as is.
 

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The issue is frequently over dramatized in my experience. I have had a 1976 450 slc for over 10 years, driven 30k miles, both in town and highway in southern Missouri. Only had vapor lock a few times. Mine is in excellent mechanical shape and only run ethanol free fuel. My vehicle does run on the hot side, though.

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450slc5.0cab 280sl5sp 280se4.5 500se+500slAMG +250seStkW108 350sl4spdX3 500secEuro
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The issue is frequently over dramatized in my experience. I have had a 1976 450 slc for over 10 years, driven 30k miles, both in town and highway in southern Missouri. Only had vapor lock a few times. Mine is in excellent mechanical shape and only run ethanol free fuel. My vehicle does run on the hot side, though.

Sent from my SM-G960U using Tapatalk
75 is a d-jet, and d-jets without the cats can experience vapor lock. So I imagine it’s much worse with the cats in the engine bay. Think 25-30 psi vs 80 psi, and you can see how fuel will vaporize at 25-30 psi much faster.
 

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Discussion Starter #5
Thanks for the replies......which brings me to another question....was there even an official recall or advisory by MB to relocate the cat under the car or was this something that some people did on their own to alleviate the problem?
 
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