cthirtysizzle

So I've noticed a few things slightly change with my C43 in the past few months. My car doesn't seem to be the beast it used to be and that bothers me. : )

My C43 normally runs around 80-90 degrees, but now seems to run in the mid - upper 90's (never goes over 100, but get's close). Told my mechanic (who is awesome), and he checked everything out for me and we ended putting a new thermostat in, but that didn't seem to fix the problem.

Another thing is I was getting oil level lights about every 2-3k miles. I literally would carry a quart or two of Mobil 1 0W-40 in my trunk at all times because of this. Had my car checked for new leaks (had some fixed a while back), no major leaks although I do smell burning oil on start up sometimes, so we checked and checked and found a small valve seal leak (slight leak, like not even dripping), so I had that fixed, also replaced the oil level sensor, and just got another oil level light this past weekend. : /

I'm not really sure if I'm over analyzing, but I keep a close eye on my car and know it pretty well and I feel like something's up but I'm not exactly sure what. I feel like I don't have the same power I once had, and the temperature/oil burning things kinda bother me. Is there something I'm missing? Should I get a valve job? I'm not a total engine expert, but if someone can point me in the right direction would definitely appreciate it. Thanks.

RPB

Sounds like the issue I had on my C36 w/ the exception of oil loss, getting new water pump, thermostat, belt, and tensioner right now. Spark plugs too. Are you hearing any sounds, I could hear my water pump squealing but did not realize it was bad till we got into the 90's here in DC. Mine got up to about 102 at its peak, typically lower to mid 90's though. The loosing oil issue sounds unrelated to this, not sure. Best of luck!!

cthirtysizzle

No sounds, have a new water pump. Think it may be time for a valve job, gonna get it tested for oil leakage this week maybe.

503C43 ////AMG

any codes??

cthirtysizzle

idk. no lights have gone off, but I'm gonna take it to get checked out hopefully this week.

DRBC43AMG

How many miles do you have on the clock?
Upper 90's is definitely a bit too high
Could be several things, apart from the usual tuning items (plugs, wires, filters air and gas)
1. Check the water expansion tank cap checked. Mine was heating up a bit and after a change for a new cap (cheap from the dealer), no more problems again, with good pressure in the system
2. Clogged water radiator (get a good flush done)
3. Water passages clogging up with scale (specially if you live in a region with lots of limestone)
4. Head gasket(s) going
5. Valve guides worn and/or valve stem seals worn

Get the car on a Star and read the codes. That would be a first priority and good way to see if anything is wrong.
Good luck and keep us posted
PS Mine is also a bit sluggish and needs some new plugs etc. I'm getting close to needing a service

tri-star tech

Are you sure your oil level sensor isn't going bad?

C43AMG

Saaboteur

You said you were getting the oil level lights, but didn't say specifically if the oil level was actually low when checked. Was this the case?

Another thing to check are the PCV check valves. If these have failed, it could lead to some oil loss.

More comprehensive would be a leakdown test. Not just a compression test, but a leakdown - this will tell you specifically if there are any fundamental issues with the engine, and if it is going to be expensive (top end) or very expensive (bottom end) to fix. Ask specifically about the leakdown, not just a compression test. Some techs, surprisingly to me, don't know the difference.

cthirtysizzle

good stuff, thanks for all the great advice.

@DRBC43AMG - 137k miles, and I agree, upper 90's is definitely not normal for my car. Hopefully taking it into the shop tomorrow or maybe over the weekend and I'll check to see if any codes come up and post them here.

@Saaboteur - When I was getting lights, levels were low. I would check after letting the car sit for a bit and checking on level ground. Either way, replaced the sensor and fixed any visible leakage, but I'll definitely get the Compression & Leakdown tests.

ps. do any c43/c36 owners ever do meetups in l.a. anymore or is that a thing of the past?

MarcusF

Saab is right. If the valve guides or cylinders are leaking, a leakdown test will tell you what you want to know.

Three weeks ago there were several 202s owners and their cars at the OC meet. There were even a pair of W209 DTMs. Not fakes, mock ups, or conversions, but the real deal - A 200 MPH coupe and a 186 MPH cab.

cthirtysizzle

Quick update, finally had a day off to stop by my mechanic's shop. He did the compression and leakdown tests and said there was some oil getting by the valve rings, but not enough to warrant a valve job.

He also checked a few other things and said my Mass Air Flow Sensor was running "rich". He reset everything and my car drives like a beast again and the running temperature seems to have dropped as well. Crazy.

Seriously the best mechanic I've ever had hands down. Honest, trustworthy, and knows more about our cars than anyone I've ever talked to hands down. If you guys ever need a recommendation for a great mechanic/mbz specialist in l.a. let me know.

MarcusF

So who is the mechanic? MB Motors?

cthirtysizzle

Jim @ Mercedes Benz Transmissions in San Gabriel. Seriously the best mechanic I've ever had.