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Marty, Mercedes Technician
Category: Mercedes
Satisfied Customers: 53016
Experience:  Bosch Certified Master Tech. Over 35 years experience.
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I own a 1991 Mercedes 560 SEC. This is a weekend car and is

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I own a 1991 Mercedes 560 SEC. This is a weekend car and is in really good shape - but it needs a few things down to it. It has a rough start but then smooths out. When I took it in here is what my local shop told me after performing a fuel leakdown test:

Hi Scott, the work he is recommending is very normal for this car. The only thing I would question is the fuel filter and fitted fuel hose pricing. I would combine that repair with the accumulator repair. All of the items are in the same area and he should be able to save you a little on the labor if all are done together. Do you know if you're getting new spark plugs in the tune up? The accumulator will only fix a hot restart problem. If you're having other starting problems there could be something else wrong. Let me know if you have any questions. I'll be happy to help.



Customer: replied 7 years ago.

OK thanks Marty. When the car is warmed up the start seems fine - so this is more of a cold start issue. Maybe they have misdignosed it?


Did you think 4k for head gaskets is right? I know it's less than $200.00 in actual gaskets but it is a very labor intensive job to disassmeble the engine.


Also, I can ask about spark plugs - as that may be a good idea to make sure they are in top shape.




They've definitely misdiagnosed it if it's a cold start problem. The accumulator will not affect cold start. I would avoid the head gasket repair if at all possible. The price is about right but only if it includes a complete valve job. Is it poor starting cold or poor running cold or both?
Customer: replied 7 years ago.
Sometimes it fires right up - other times I have to give it some gas right after start - to which it will idle up rough and then settle down. Once the engine is warm - it runs smooth as a top. Again, I would say intermittenly I have this problem.
If the shop is seeing a loss of fuel pressure and they've diagnosed it as being the accumulator by removing the bleed hose at the accumulator and checking for leakage from the unit when the car is running then I would let them replace it but it won't fix the problem. If they only think it's the accumulator then don't replace it just yet. Your intermittent cold start and what sounds like a misfire problem could be due to oil fouling on a plug due to bad valve stem seals or an injector that leaks down or many other things. If they haven't duplicated the problem then they have more work to do before it's fixed.
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Customer: replied 7 years ago.

This is exactly what they were seeing - as I went into his shop and he had the hose clamped off and that's how they made the determination. Sounds like we'll need to do this at a minimum - but may not fix the problem.


Thanks - your answers were very helpful.

That's the correct thing to do. Then retest the system. Good luck with it!


And thank you for the bonus!



Customer: replied 7 years ago.

OK thanks!