Hello all, my car search finally came to an end after looking a a ton of cars.

I found a 1991 190E 2.6 in great condition. It has 104K on the odometer, interior and paint look great, and nearly everything works good.

However, I did have a few questions and am hoping you experts can steer me in the right direction.

1. The ac works and blows somewhat cold, however I would like it to be colder. It has already been converted to 134A, so can I just buy a can of the stuff and recharge it?

2. The air and heat blow almost completely out of the two middle vents. The far left and far right vents are VERY weak or don't blow at all. What could be the cause of this? If I shut the middle vents the side ones do blow, just not when they are all open.

3. I let the car sit and idle for like 5 min and noticed that the electric fan came on. Is this a normal occurrence? (It was about 90 degrees today and it was after an hour long drive)

4. I noticed that as it was idling, the outside temp. gauge kept climbing up, eventually reaching about 104 degrees. However, It was not nearly that hot outside. Once it was driving it was displaying a good reading, just not idling. What could be the cause of that?

5. The car seems to look and run great, but it didn't come with any maintenance records. Is there anything I should do right away, or the near future, to the car?

6. As a Mercedes and 190E newbie, what would you guys recommend for oil change intervals? How about the type and weight of oil?

Thanks for any advice you all can give. Here are a few pics:

Dustin, congratulations on your recent purchase. Appears to be a well-maintained MB automobile.

Regarding Item 5: recommend changing all fluids (brake fluid, coolant, oil, differential, power steering and transmission fluid) and filters (oil, power steering and transmission). Be sure to use either MB coolant or Zerex G-05 at a 50/50 mix.

Regarding Item 6: There is a chart in your Owner's Manual that provides guidance for oil weight, and the Maintenance Booklet likely recommends oil/filter changes every 7,500 miles. Factory fill for that vintage engine was 15W40 mineral oil or you can switch to Mobil 1 15W50 ... that's what I run in our engines of that vintage. Mobil 1 has swell agents to prevent gasket/seal leakage so disregard the horror stories about Mobil 1 causing leaks in older engines that previously used only mineral oil.

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Fred Hoelzle

3+4: You need to figure out if its a flow or pressure problem. First check coolant level, then replace thermostat....go from there.

6: Use Diesel grade oil -- 15-40 Rotella-T is the usual favorite and can be had cheap. Change intervals are debated too, but the more often you change the better -- period. I personally do 3k no more than 4k between changes as I'm planning on keeping both my cars until the day they give up.

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2016 Monsoon Gray Audi Allroad - 21k
2008 Black Mercedes E350 4Matic Sport - 131k
2014 Jeep Wranger Unlimited Sahara - 62k
2003 Gray Mercedes ML350 - 122k

1. The ac works and blows somewhat cold, however I would like it to be colder. It has already been converted to 134A, so can I just buy a can of the stuff and recharge it?

Have the system inspected, both for system pressure, leaks, consider a system refresh with a new drier.

2. The air and heat blow almost completely out of the two middle vents. The far left and far right vents are VERY weak or don't blow at all. What could be the cause of this? If I shut the middle vents the side ones do blow, just not when they are all open.

You may have an issue with the hvac system, since you should not be getting any heated air through the center vents. Mercedes during this period didn't think it was a good idea to have heated air from the center, only the sides, footwell and upper dash vents get air heated by the heater core. The center vents only get ambient temp and air conditioned.

The flow to the outer and lower vents are controlled by vacuum powered "doors" which open or shut depending on your push button selection. A faulty vacuum connection (unlikely) or a worn out vacuum valve (more likely) will cause a door to stick open or shut.

Bad news . . the whole dash and center console has to come off to access the vacuum valves.

3. I let the car sit and idle for like 5 min and noticed that the electric fan came on. Is this a normal occurrence? (It was about 90 degrees today and it was after an hour long drive)

Your engine uses a viscous coupling clutch to activate the fans, unlike early 4 cylinder engined models that used a temp sensor activated fan clutch. So long as the fans come on to keep the engine temp at a reasonable temp (lower than 110-112C) it's likely working okay.

4. I noticed that as it was idling, the outside temp. gauge kept climbing up, eventually reaching about 104 degrees. However, It was not nearly that hot outside. Once it was driving it was displaying a good reading, just not idling. What could be the cause of that?

The outside temp/ambient temp LCD uses a license plate holder mounted sensor, because the sensor is designed to warn a driver of road temps that are near freezing and the ice hazard. It could be that the temp was reading properly for the area, or the sensor is defective.

5. The car seems to look and run great, but it didn't come with any maintenance records. Is there anything I should do right away, or the near future, to the car?

The M103 six is somewhat notorious for head gasket leaking, so watch out for oil sludge in your coolant. Without records, consider starting service to create a baseline date for all fluids, including the ps fluid, brake fluid, differential lubrication, coolant, trans fluid . . . also the sunroof grease.

4. normal, no air flow over temp sensor when you are not moving.

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85 300 SD ~ 115K
82 500 SEC Euro ??K
78 450SL 164K

Thanks for the replies.

What is the advantage of using oil meant for a diesel?

After playing around with the climate control today, I noticed that cold air is only coming out of the center vents, while the heat doesn't seem to work at all. Any ideas as to what to check for that?

The air is decently cool when driving down the highway, however when I stop the car at a light, or at idle, it warms up considerably. I'd like it to be ICE COLD even at idle.

In an effort to fix this, I went to the auto parts store and bought a can of coolant, but when I hooked it up to the system, the gauge told me it was already at max pressure.

So, is there anything else I can check myself as to why the air isn't too cold? I don't want to take it to a shop unless I absolutely have to because of the expense.

[QUOTE=Dustin.;2700865]

I found a 1991 190E 2.6 in great condition. It has 104K on the odometer, interior and paint look great, and nearly everything works good.[QUOTE]

Congratulations on a great buy. I once owned a 190e 2.6 and later sorry I sold it.

R134 into a system that was originally designed for R12 is a compromise and will never be as cold as original. Also I.M.H.O. M.B. spent a lot of money on designing the W201 series, perhaps not much of it on the air con system - those of us with high summer temperatures seem to find this.

Heat generated by the heater doesn't come from the centre vents however A.C. cooled air does. If you find heated air coming out of the centre vents then the inside core and components may require to have insulation repaired (a big job)

Normal operation. You will find that in traffic and or with the AC in operation the engine temperature rises and falls. Before the electric fan operates you should be able to hear the viscous fan come into operation. I.M.H.O. '80's Benz's destined for countries with hotter ambient summer temperatures should have had a more generous engine cooling system.

Sometimes hot air escapes forward from underneath the car from the radiator or engine pies and creates a false reading on the outside temp sensor.