I have just started my love affair with a 1991 190e 2.6 and in the first month, having never worked on a car at all, I've done a head gasket replacement and all sorts of things and will be putting up some diy video and stuff soon for those that are interested.

So having scoured every forum and page I could find as I worked along, several simple questions were hard to find answers to, and often strange debates erupted. I thought for noobs like me it would be nice to have answers to the silly basics in one place and I'll ask harder questions on other threads. So here they are:

Temperature gauge - what is the unnumbered line between 80 and 120? Is it 90 or is it 100?

Normal operating temperature - it really seems like this should be an easy question, but it always starts a lot of debate. It's my understanding that all cars operate at fluctuating temperatures, higher under heavy load or hill climbing, and highest when idling still with little air blowing by. Most cars don't have an actual temperature gauge, just something that suddenly says it's too hot if that happens. In a car like that you wouldn't know what's happening with the engine temp and just live your life unless it heated up and a warning went off. In a 190e you have an actual temperature gauge, and those of us with OCD can think of little else. My car seems to stay around that line between 80 and 120. Prior to doing a head gasket replacement, flushing the entire cooling system, new thermostat, 50/50 zerex g0-5, all new fuses and other stuff it would heat up a little faster but I can let it idle for about 20 minutes (at least here where it's 60 outside but I will soon be in hot Southern California) before it gets hot enough for the auxiliary fans to kick on.

Cool harnesses - or whatever you want to call them, where you put in a modification that makes your auxiliary fans kick on at 92 instead of the normal 110 I believe - is this a good idea? Based on your feedback on the above question I guess we will see - if the car should normally operate at a variety of temperatures between 80 and 110 before the auxiliary fans come on then everyone is worried about nothing right? Or if our cars should just be hanging out around 80 I think most of us may have a running temperature issue.

Dots on speedometer - there is a single dot at around 35, a double dot at 60 and s triple dot at around 95. What are these? Are they shift marks? They seem to be pretty high rpm shifting suggestions if they are.

Speedometer - out of nowhere my speedometer only comes to life when I hit about 20, otherwise I have to tap in front of the speedometer to get it to climb before it gets to 20 mph. What's up with that?

Coolant - MB or Zerex G-05 only, correct? Mixed 50/50 with distilled water?

Oil - I actually got all the records for my car and it has always had mobil1 0-W30 and a matching premium mobil1 oil filter, so I stuck with it. Is that a good thing?

Gas - only the premium high octane.

Other fluids and maintenance - since history is better than the owners manual, is there a schedule that should be compiled of what to flush and or refill with what specifically for brake fluid, power steering fluid, transmission, etc? My car has 120k original miles on it and I had to do a head gasket replacement right off the bat and several forums mentioned that 120k is about when you should expect to do that. MB definitely doesn't tell you that! So I just wondered if there is a kind of reality based comprehensive maintenance schedule or if we should create one. Just a thought, any input appreciated.

I'll leave something that will entertain you from the mistakes I've made working on this car at the end of each post:

I was furious with the guy who filled my car with gas and didn't get the lid on all the way and now my fuel filler door was stuck and couldn't be opened. A few of us looked at it, pried at it, did everything to open it to no avail. Then someone said, "unlock the car." And of course it would now open, nobody had done anything wrong, it locks with the rest of the car as a security feature.

 

If you need any assistance with your DIY work you can check out our tech articles here.

-Luccia

 

I've actually used your tech articles several times over the last month, good stuff.

By the way gang, on the engine operating temp question above, in doing some more reading I find several other people saying their 190e 2.6 tends to just stay at about 80 degrees - how is this possible?

 

Really quiet in here.

 

Just got an 88 190e w201...looking for a copy of the owner's/operator's manual/guide......the climate controls and some odd buttons are perplexing.

 

I've owned my 93' 190E 2.6 for about 2 years now. Done a few things to it such as head gasket, new radiator "Nissens", all tune-up parts e.g. OEM PARTS ONLY, spark plugs,wires,distributor etc... My 190e is always running just a hair above 80 degrees temp. Probably due to new radiator, thermostat, Mercedes blue coolant and of course a coolant flush. Love my my 190e and got it for $1250 bucks! Learned one thing about these Benz. Use OEM parts and the car will not let you down. Guess I'm just old fashion but I always use OEM parts.

My next project. Just started to have hard start up in the morning. Takes about 4-5 cranks on the ignition key to start. Then idles terrible, rpms seem to low until it warms up then runs normal??

 

I did all the same things - super flush, head gasket, thermostat, nissens radiator, all tuneup parts, and a lot more. It runs awesome, but it always stays near 100 - is that the line between 80 and 120?

 

What brand and degree is your thermostat? I use a Behr OEM - Thermostat; 87 Degree C.
Yes, I believe the line mark between 80 & 120 is 100.

Today I found my 10 AMP fuse on my OVP relay blown! My rpms are a lot better and engine runs smoother but still a little rough starting up cold in the morning. I think the culprit might be the cold start valve but not really sure yet. I will work on that next weekend.

 

Temperature gauge - what is the unnumbered line between 80 and 120? Is it 90 or is it 100?
I believe it is 100.

Normal operating temperature My car seems to stay around that line between 80 and 120.
That is normal operating temp - around 100C.

Prior to doing a head gasket replacement, flushing the entire cooling system, new thermostat, 50/50 zerex g0-5, all new fuses and other stuff it would heat up a little faster but I can let it idle for about 20 minutes (at least here where it's 60 outside but I will soon be in hot Southern California) before it gets hot enough for the auxiliary fans to kick on.
Aux fans will rarely kick on, unless A/C is running. Normal.


Cool harnesses
I don't know what that is.

Dots on speedometer - there is a single dot at around 35, a double dot at 60 and s triple dot at around 95.
Since they are yellow, like the Kilometer scale, I am guessing that they are possibly common speed limits in Europe. ???

Speedometer - out of nowhere my speedometer only comes to life when I hit about 20, otherwise I have to tap in front of the speedometer to get it to climb before it gets to 20 mph. What's up with that?
Could be speedo, could be cable is worn. Hard to say.

Coolant - MB or Zerex G-05 only, correct? Mixed 50/50 with distilled water?
There are many coolant options available. Most are cheaper than MB!

Oil - I actually got all the records for my car and it has always had mobil1 0-W30 and a matching premium mobil1 oil filter, so I stuck with it. Is that a good thing?
Mobil 1 is OK, if it is the RIGHT Mobil 1. Should be "Formula M 0W-40", per the MB Site that lists which products are "MB Approved" for the car. In this case, it is Standard 229.5, which shows which M1 oils are approved. Look here https://bevo.mercedes-benz.com/bevolisten/229.5_en.html
Might be able to find the approved Coolant types also.
I use Amsoil 5W-40 Full SAPS on mine (also approved on the Bevo site above): http://www.amsoil.com/shop/by-produc...?code=EFMQT-EA

The M1 filter is a very good quality filter. Other good options are Mann and Mahle.

Other fluids and maintenance - So I just wondered if there is a kind of reality based comprehensive maintenance schedule or if we should create one. Just a thought, any input appreciated.

Flush brake lines. I used Amsoil DOT-4 Synthetic fluid.

Flush and filter change on Power Steering Fluid. Easy DIY. I used Amsoil PS fuid, and a Mann H-85 PS filter.

Hope that helps.