scb71

Having a hard time trouble shooting an issue with my 2007 S550 and as the symptoms expand I figured I'd start a new thread instead of hijacking another that might be different. PLEASE share your thoughts and experience. Your input is highly appreciated here. I'll try to share the details:

Issue one-
The car started having a very short (2-3 second) growl sound upon startup. You can hear it clearly inside the car but it's a little more difficult to hear if you are outside with the hood popped. The sound might be considered a whirl sound but it is a deeper sound and not high pitched. It last for a very short moment and then is gone. Car drives fine and there are no ongoing sounds or noticeable symptoms. Because it is so short my MB indy is having a hard time committing to a diagnosis - and is somewhat reluctant to dig deep unless it lasted longer thinking that it might end up just being a guessing game until the noise gets worse or lasts long enough to pinpoint it. I am obviously not pleased with this recommendation. FYI - the noise happens if the car has been sitting for maybe 10-15 minutes. If you stop and restart immediately it does not happen again right then.

Symptom 2 - could be unrelated?
It also has a periodic slow start. The car sometimes starts just fine. Other times it takes a few seconds but so far it always does start. I am concerned this might not always be the case and don't want to be stranded or need a tow.
It doesn't matter if it is cold or just stopped and restarted. We were doing this in the lot at my indy mechanic this morning. Start car normally. Stop. Start normally. Stop. Start delay - turns over for maybe 3-5 seconds and then starts. Stop. Starts normally. Stop. Short delay starting. Etc, Etc.
I have read threads about the CPS which apparently goes bad often but those symptoms appear different. To date the car has never died on the road. Secondarily so far it has always started but is just delayed.
Could this be a starter or a started solenoid? Is that easily tested? Can I do it myself?
I asked the mechanic and he said they could load test the battery first and then move to replacing the starter. I don't want to just pay for a new starter without diagnosing it somehow but it almost sounds like he thinks that is the only way to do it. He is opining that there is no guarantee but it could be that the starter is weak and something is not retracting fast enough - which might also cause a noise???
Does any of that make sense?
I asked about testing and he did say they could test amperage but that might not tell them what they need to know.

FYI - last starter battery replacement was maybe 3 years ago. I bought the battery at the parts counter and installed myself. Can obviously do that again but would like to identify the real problem before just throwing money at it. I am beginning to lose faith in my car after many years of good service. Problem is that the car really isn't worth anything for trade these days (even with low miles at 70k) but it is still a great ride if not worried about the reliability...

Thanks for your help

alx

i would wait on both issues until they become worse and narrow down the usual suspects.

DaveW68

It's definitely not the starter battery or the alternator. The starter battery either works.....or it's completely dead. There is no in-between, such as the engine turning over slower when it's starting to go. You could have a completely normal start....and the next time you go to start the car, it is dead and needs replacement. If it is in fact a battery issue, it would be more likely related to the accessory battery as everything in the car except the starter runs off of it.


The worst thing you can do is start throwing a bunch of parts and money at the car. You could spend hundreds or thousands of dollars and not fix a darn thing as they try to figure out what the problem is.


IMO, you should take it to your local Benz dealer and let them diagnose it. They might be able to pull codes on their STAR system that your indy can't. Sure, you can save upwards of 25% with an indy, but what good is that if you're throwing money down the drain as they throw time and parts into trying to figure out the issues? I only use my indy for maintenance, not diagnosis of problems.

scb71

Appreciate the replies. Dave - I hear you but there are several Indy's here that all have STAR including the one in question. MB is all this shop works on and he has a very good long standing reputation with MB. With that said, I may not be feeling the same way myself at the moment but at least they know these specific cars.

I would absolutely take it straight to the dealer where I originally purchased it but believe it or not I have had very bad experiences with them on my S class and also a GL - both of which were purchased there by the way. I hate that but because of that I am likely very reluctant to buy another MB at all. My experience with service at the dealer was simply throwing parts at things as you say which worked fine other than frustration when they are under warranty but my S class is well out of warranty. Along this line of thinking I recently traded my GL for a Lexus LX and the GL was still under warranty. They had replaced the front air springs three times and it still had the same noises... I got rid of it a year before the warranty ran out simply b/c I did not want to deal with it any longer.
Point being I have no faith in the dealer. Really hope I don't have to go back to them again. Only good note is that I would have a a loaner car to drive.

DaveW68

Your car having no warranty makes it even more plausible to have a MB dealer address the issues if your indy can't figure it out. If you don't like the dealer you purchased the car at, then find another. I'm sure a Google search can help you find another that has a good record of customer service.


If that isn't working, then you should probably follow Alx's advice and wait until the issues become worse and more apparent.

Mike5215

My 10 had a slow start...starter motor cranked at a normal pace but sometimes took longer than usual to catch. Dealer diagnosed weak battery, replaced and no problem since. As for the noise, there's a lot of racket going on under the hood at start up. I think it's how the ECU gets all the juices flowing. Fifteen seconds later it's over and you just hear the idle.

I'd replace the starter battery (3 years is old enough to warrant replacement) and keep enjoying the car.

Gordon Cooke

wow I sure do hope you are able to respond after all these years. I am in the same exact spot. Car has been great up to this point but now with the Howell on start up and the occasional sluggish start I am getting worried about its reliability over 100k miles. This is the only thread I found that mentions both of these problems together. The howling came first for me but I am just recently noticing the sluggish start. I already have a new starter battery. What was the final solution with your car?

Arrie

Almost 100% sure it is the starter. If you are diy you can replace it for just a couple hundred $.

You didn’t mention how old your car is. My E550 was almost 10 years old and I already replaced starter in my 2013 S550.

BOTUS

guy in the UK described sluggish start - but it turned out its cranking at the normal speed - but sometimes has a long cranking phase - before firing

this is totally different info and you can't muddle such terms without taking people in the wrong direction

long cranking, the odd stall and a stutter at low rev - plus ultimately refusing to start when hot - can all be symptoms of a failing crank position sensor... these are known "service items on a Mercedes" and an easy DIY fix at home with few tools and cost less than $60 - if your is >50k miles and 8 years you should just fit one

nath_h

Slightly off the topic, but not sure how you guys find indy mechanics charging less than the dealer. I've stopped by 3 indy shops in Des Moines, Iowa to get quotes on changing the spark plugs and do a brake flush. 1 was very slightly cheaper than the dealer, one essentially the same, and one more expensive than the dealer. I went with the dealer. I should have changed the plugs myself--$30 per plug for the part--uggg. Is this a quirk of my area that all shops are near parity in cost?

BOTUS

in the UK a good ex merc independent is twice as knowledgable and 66% or more cheaper

however there are only about 5 such garages people believe worth using across England and only 1 that is any good

you'll find 20 merc brand experts in every town - these are just able to strip the drain plug

UK main dealer is $300 an hour and mostly employ sacked MacDonalds workers who's only experience of cars is from a PS5 !!!

Gordon Cooke

2008 with 98k miles. I did not know the starters commonly went on these. Could the starter be producing that growl on startup independent of the occasional sluggish start? I am DIY though time seems more and more limited these days...

BOTUS

needs the video / audio one man's growl, could be a chirp or a squeak to another