Hi guys,

I just joined here last night. Thanks to everybody, especially the Techs that put all your valuable time in helping out. I know it can be frustrating at times.

Anyway, I searched and searched last night, learned a lot, but I still have some questions. My Sis's 1992 190E 260. I haven't seen the aux cooling fans kick on yet. The gauge stays just above 80 until stop and go traffic or extended idling. Gauge goes way up then, however it's never gotten in the red. Manual says expect that. I read several threads last night arguing for that and against it.

I checked the temp with an infrared gun. It was 230deg F on the top of the tstat housing and 190deg F in the recovery bottle. I turned on the A/C and nothing changed. Same when I turned heater on. I'm going to work on it today.12V straight to fans to verify they are in working order, then go back up the connecting wires to see what I can find.

Is there somewhere I can view the engineers operating theory on how this cooling system was designed to work? I could use some help too with any diagrams somebody could share that show temp switches, wiring color codes, voltages,amps, etc., on this cooling system.

Is thata temp switch I saw in the coolant recovery bottle or just a coolant level sensor? If so does it turn the aux fans on when the coolant hits 200deg F? Like I said, 190deg F was the highest I saw in the bottle. (Was this a stupid question?)

I read a postthat somebody had given one of the moderators a drawing diagram of the vacuum system, hoses, etc., on a 190E. I would really be appreciative if somebody could email me that file too.

I was impressed with the member that wired up his own system, bypassing everything and making the aux fans turn on when the ign switch was turned on. He says his temp stays at 80 now.

Thanks in advance for any help,ideas,diagrams,pictures.

Johnrude
atcskeet@aol.com

 

Hi John, welcome.

The aux cooling fans are turned on by th following:
1) When the AC is switched on.
2) When the temp sensor on the cyl head closes contact

The sensor in the reservoir is for coolant level.

Also, because the fans are "motors" and pull largeramps, the actual current to the fans is switched on by ahigh Amp "fan relay". The fan relay is triggered by a small signal from the cyl head temp switch. So check the "fan relay" operation as well.

Also, a problem that happens to mine occasionally, is that air can get trapped in the cyl head, and basically allow the coolant temp sensor to be reading an air pocket instead of moving coolant. There is actually a bleeder/burp screw on top of the thermostadt housing for releasing this air. You start the engine, allow it warm, then slightly loosen the screw, allowing the air to escape until collant begins to bleed out, then retighten the screw.

Blue

 

Hi Blue,

Thanks for the reply. I got the problemfigured outearlier this evening. The first thing I did was unplug the starboard aux fanand put 12v straight to the motor. It came on immediately. So I plugged it back up and started looking for the temp switch on the head. I unhooked the one wire switch first, fired the motor up and hooked up an ohm meter to the switch and to a ground point. As the motor warmed up the ohms gradually decreased. So I figured it was working correctly, checked the dash and sure enough the temp gauge was sitting on zero. I plugged the switch back up and temp gauge jumped to 80....eliminated that one.

The next switch was closer to the front of the motor, about in the midddle of the head. It had two wires hooked to it. I tried checking the resistance on both terminals. The readings were all over the place and the port terminal was either way higher or lower, can't remember. I had the A/C running the entire time and by now the Tstat housing was reading 100c according to my temp gun. The temp at the two terminal switch was around 100c also.

Next thing I did was run a jumper wire from the port terminal on the switch straight to ground. The result sounded wonderful. Both fanskicked on WFO. I don't remember if anything happened when I grounded the starboard terminal on the switch.

Anyway, I've got to round up one of these temp switches and I'll have the aux fans back working. Can I get one of these switches at AutoZone,Advance,Napa, or any of these type stores, or do I have to get it from one of the advertisers on this site or Mercedez?

While I'm hot I may as well try to fix the cruise control and the tripometer. The cruise control doesn't work at all. Any ideas on where to start?

The tripometer is set to all zeros, and the numbers don't budge. What is the usual culprit for this and can it be fixed.

I ain't skeered of taking the dash apart. I love tearing into something to see how it works, then putting everything back together. The way I look at it, every man puts his pants on one leg ata time, just like me. If somebody else can do it, so can I. I'm even studying Jethro's book on how to become a brain surgeon.

It's all just like cooking. If you can read and you have the tools and ingredients, you can cook!

Once again Blue, thanks for the help, and if you have that diagram of the vacuum schematics that member made for you, I sure would like to have a copy of it.

Disregard the cruise control and tripometer questions. I just did a search and found enough info to get me started on both. This site is turning out to be very helpful.

I still would like to have the vacuum schematic though

Johnrude

 

>It's all just like cooking. If you can read and you have the tools and ingredients, you can cook!

You sound very capable. And your statement above signals, in my opinion, the only real difficulty in repairing these cars, which is gettinginformation. Most manuals simply scratch the surface, and its likely due to the small market size of capable MB do-it-yourselfers. I wish someone would study and write about why people like us choose to buy, keep, and repair ourselves, these cars. Maybe because we can? What we as 190 owners need to do, is group together in clubs like this one, and help keep each other's cars alive.
I believe NOW, is the time to buy a 190, and I believe shortly they will become one of the most sought after collecter's cars MB has ever produced.Blue

ps I'll get that drawing for you soon; right now I'm supposed to be working on a Law project due tomorrow. Blue

Post some pics of your car!

 

Hi Blue,

My sister stole this 190E about a year ago for $3000. She has a 2000 Maxima she uses as her daily driver. I borrowed the 190E about a month ago for an errand. That was when I noticed all the problems. The first thing I had to do was replace all the front wheel bearings. They were roaring pretty good, especially the left front outer bearing.

That bearing was about ready to come apart. The race was eaten up too.....boy was it fun getting it out. It had gotten so hot it was welded in place.

Just replacing the front bearings made it sound and feel like a new car...almost. I can hear the 185k miles on the rear end differential now. It has a good while longer before it will need tending too. I've never done a rear end before, so I'll be taking it to my buddys foreign car repair shop so he can hold my hand on that job...plus he's got a lift.

You have a great point on forming a 190 owner's club. It would make keeping one up to snuff a breeze.

I belong to Dieselstop.com also. I have an 03 F350 truck with a 6.0l turbodiesel. There is a special section on that board for 6.0l owners. I haven't had to post a question yet. The archives have every Q/A already there. It is truly great.

I'm all in if you want to start up a 190 group. I'll try to post some pics tomorrow.

Thanks,

Johnrude

 

Okay,

Aux fans working like they are supposed too now, thanks for the help. Now I need help with the cruise control. I have searched and searched this site and others, but I can't find where or what I'm looking for. The CC switch moves fine. I need a starting point.

All help would be appreciated.

Johnrude



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