Hi guys,

I recently bought a gorgeous '97 e420 and I love it. Recently i was stuck in a really huge backup on the road, stop & go for over 30 minutes with 100°F sunny weather...

My engine temperature got really high (near red) and when i restarted the car in the evening it said I had low coolant. I stopped at some random mechanic shop the next morning and the guy added some orange Prestone coolant in it. After reading this forum, it seems like it was not such a great idea.

He added maybe half a gallon from what I saw, maybe a little more. So I have 2 questions:

1-) Is that enough to cause damage? Should I get all the coolant flushed and replaced it with MB coolant?

2-) I did not check the coolant level when I bought the car, I am assuming it was low already... If not, what could cause losing coolant like this during heavy traffic in extreme heat, is that normal? Or is it an indication that something else is wrong, if so, what? I never found any leak where I usually park the car.

Thanks!

 

I would probably flush it. Even if the coolant added wasn't going to cause damage, the fact it overheated probably means you could use new coolant mixture anyway. Plus, it might react poorly or damage your water pump. Depending on where you are in Texas, you might do 60/40 water/coolant (this will absorb heat better but will also freeze easier) and some Redline Water Wetter.

You can use Zerex G05 from NAPA or O'Reillys instead of MB brand coolant, it is the same formulation. I would try that first and see if that fixes things.

 

Also replace the thermostat while you have all the coolant out. (Your current thermostat could also be gone...)

 

Found some Xerex G-05 at NAPA, I guess a 60/40 water/coolant ratio would be good here in Dallas.

Now about the thermostat, is that expensive to change?