CC300newguy

Hello Everyone!!

Just got a 2008 C300 Luxury RWD as my new daily. Car is good shape for being 15 year old. And has only 65K miles on it. It obviously have some issues due its age but I am happy to have it.

I started with an oil change, air filter change, headlamp bulb replacement and aligment, new tires and a deep clean. Car came with new brakes

However I found some things that I need to work on.
1. Horn is not working. Fuse diagrams show the fuse number and relay to check, and they seem to be ok. However there are two 31A and31B slots, and the fuse is a 2 prone fuse. Have any of you guys work on this before? Does it need a three prone fuse? I will check the horn connections, but wanted to ask you guys first
2. The interior lights on the glove box and passenger footwell were not working, I replace the bulbs with some LED that I had from a previous car. However, the light in the foot well is always on while the vehicle is running. IS this a normal behavior? Is there any way to turn that off once we start driving it?
3. Have you guys used LED on the instead of the head lamp mini bulbs?
4. I have notice the temperature reading is always under 80 on the cluster, is this the normal temperature expected?
5. Have any of you use the pre assemble quick struts systems that are sold online? or go for the OEM type. While trying to save some money, I have considered the other option.


Next fixes / updates are the serpentine belt, new sparkplugs and will need urgently some front struts.

Thank you guys!
Cheers!

JettaRed

iTrader: (1)

1. Fuses only have two prongs. Are you referring to relays?
2. Get rid of the LED lights and install what is specified in the operator's manual (or elsewhere).
3. See #2. These cars are very sensitive to electronics.
4. Temp should run right around 200°F or right around 93°C. (Get a scanner)
5. Stay with OE, OEM, or genuine parts. FCP Euro, Pelican Parts, AutohausAZ, ECS Tuning, and RockAuto are good sources for parts.

Get yourself a Mercedes-specific scanner!!! My personal preference is LAUNCH Creader Elite BENZ, but iCarsoft MB V3.0 and Foxwell NT510 Elite are also good. Check Amazon.

TimC300

No its not normal for the interior lights to stay on. the led is probably not the correct voltage as the original bulb.

I only install the bulbs that are specified.




The Mercedes thermostat is rated for 100 degrees C/ 212 degrees F. Its even stamped 100 C right on it. You should see the temp get up to 100 C then stay there or go a little lower when the thermostat opens. If its stuck open it may not get up to temp. If you happen to need a new one the Mercedes thermostat is actually Wahler.





For replacement parts I would only install Mercedes or OEM parts. Mercedes front struts I believe are Sachs. I would not use no name brands. Ill look around and see if I can find some deals for your struts.

For serpentine belt the length should be in your operators manual in the back. Should list it in mm. I like to buy parts at eEuroparts or FCP.

CC300newguy

Thank you! will do that with the lamps.



This are the fuses I was refering too, a previous car had some like this. But I already check and there are no ATO fuses like this one.

JettaRed

iTrader: (1)

Well, I learned something new! Whoda thunk it? Well, some crazy engineer, I guess.

CC300newguy

I went to the auto parts, and got the bulbs and a multimeter. So, lamps are working fine now, and even the glove box one.
Was able to check fuse and relay and they do work, So, now need to check the horns.

CC300newguy

Hi there, I had the first long drive with the car today (around 22 miles). I started her up, and let her warm up for around 5 minutes while I got my stuff in the car and head to work. It took its time to get around the middle of the gauge but never went past that (80C is the number). The engine coolant was 150F on average (got my OBDII scan connected). It was until I got to the office and parked that it start climbing up until 210F, and then went back to 190F. I do think it got stuck open.

What type of coolant you guys recommend?

JettaRed

iTrader: (1)

Bookmark this page!

https://operatingfluids.mercedes-benz.com/

Did you get a Mercedes-specific scanner or are you using a generic OBDII scanner? If you are using a generic scanner, save it for your Honda. I can give misleading results. You NEED a specific scanner for Mercedes, like I listed above in my first response. They are all well under $200 and will save you money on your first trip to the dealer when the generic scanner can't read the correct module.

TimC300

I think 2008 should be the blue coolant. Double check by looking in your operators manual, it should say in the back under Fuels, coolants, lubricants etc. Mine says it uses MB 325.0 Anticorrosion/Antifreeze.

I use the Zerex G48 50/50 Blue coolant. It is 325.0 Mercedes approved right on the label. I find it on sale alot at Napa autoparts. I think the 50/50 is just easier to use, no mixing needed.




Do you plan on replacing the thermostat? Its very easy to do. I recently replaced a leaking oil filter housing gasket and removing the thermostat was part of it. I did not bother draining the coolant from the radiator, i just removed the thermostat and let it drain out there. It saves a step.

When I did that work I ended up buying 2 jugs of the coolant and had a little left over. Def needed more than 1.

TimC300

Ill add when removing the thermostat the secondary air pump is very close to the thermostats top bolt. Pelican parts says to remove the air pump out of the way. Instead I bought a 1/4" drive E10 socket and used my 1/4' extension and was able to reach and remove that top bolt. 3/8" is too big to fit.



The drive belt and idler pulley has to be removed to get at the thermostat so it may be a good time to replace the belt. I also replaced the pulley since mine sounded like a skateboard wheel. Make sure to torque all the bolts to spec when done. I have those specs if needed. Mark the direction the old belt goes, I keep the old one in my trunk if I ever need it again.

CC300newguy

hahaha! I know, generic scanners just give part of the information, but keep in mind that to sold the car in the US, some information should be in the OBDII port available for any scanner, pro or crappy. Should be able to read it due emission regulations... one of which is coolant temp. But yes, the specific Scanner is on the way

CC300newguy

Thank you!!! I will replace the belt, since it was part of the "I need to trust the car" repair list. Where did you find the torque specs?

TimC300

For the thermostat and the idler pulley below its 25nm.








I think the 35nm number below is if it were a new water pump and the bolt hole is not pre-threaded?. I followed the "follow-up operations" number of 25nm.

JettaRed

iTrader: (1)

OBDII is ONLY concerned about emissions-related faults. It will not detect door, wiper, trunk, brake, transmission, radio, moon/sun roof, lights, TPMS or anything else that doesn't affect emissions. That's why with these cars, generic OBD scanners are a waste of money.

CC300newguy

For all in this thread...

Thermostat is in, and working perfect.
Put new serpentine belt, air filters, air filter rubber seal, battery and spark plugs (the one in the vehicle had a gap twice the size), new sway bar links and a new horn. I did put a Liqui Moly injector cleaner on a fuel tank. Vehicle runs really nice now.... while it was not bad, you can tell a difference between nice and day.

Still need a work in progress but is nicer ride now...