I've got a 19 GLA45 and noticed the coolant is full (new from dealer) with coolant right up to the cap. This is odd as most vehicles I've owned only have it less than half full to allow for expansion. I'll check manual, but curious what other coolant reservoirs on these look like when serviced. Thanks.
Thanks for the reply. I had it towed to the dealer today thinking I may have a bad sensor or waterpump. I only started looking into it yesterday (60F US ambient) was just running errands and doing a couple speed runs for fun. Got home and noticed the fan stayed on a long time, maybe 5 min, which I thought was unusual for a cool day with plenty of cool down time before shutting off. Expansion tank full to the brim and I can hear what sounds like boiling water down by the radiator. Took it for a short run this morning of 5 miles to warm up (50F ambient) and it did the same thing. Fan shuts off and you can hear boiling from inside one of the front radiators for probably 15 min before it cools down. Definitely not getting proper circulation somewhere and it's repeatable. I've had thermostats go bad on other cars so it is something like that. I'm just not familiar with this vehicle yet. I'll be sure to post up what the solution is.If you're referring to the plastic coolant expansion tank then No, it should not be filled to the top but rather proper level as marked on its side. As you cite it's usually about halfway to allow for expansion and even when the engine is very hot it's not anywhere near the top.
Dealership service often overfills fluids. My last oil change was overfilled as well (which is actually worse than underfilled and I subsequently drained some).
Alas you have to be a watchful advocate for everything these days!
Yeah, he said they definitely shouldn't have filled to the top but did say they regularly will fill about an inch over to avoid sensitivity issues.If the expansion tank is already full where does hot coolant expand to? Pops the cover/hose and spatters into the engine bay (yeah, unlikely, but still...)?
I understand Benz service folks wanting to avoid a false positive but completely full is overkill imo.