Engine temperature and engine clicking....

[190D22]

My engine temp climed steadily when I was idling, it got over the 100C mark (the mark before the red/white 120C line). I turned the heat on all the way and it came down quickly, but I don't like this much fluxuation in my temperature. I have a brand new radiator and aux coolant pump (yes that climate control blows HOT!) But I am willing to bet it's the thermostat maybe? I have been wanting to put some water wetter in, but I won't if I have to change something out and drain the system ya know.

I also have a question about engine clicking, I notice while I was idling with the windows down and cd player off that there's a clicking that comes and goes, it does it when it's idling, it does it all the rpm's up to 1500 rpm and it goes away at 2000. It almost seems regular in pattern. Lifter out of adjustment maybe? Any thoughts? Greatly appreciated.


Thanks in advance guys.

[190D22]

Anyone please?

[The Warden]

Has the car done this while moving?

If not, I'd be willing to bet your fan clutch's dying...it ought to havbe engaged before then.

Just a thought...good luck! IMHO, the clacking does sound like a lifter...

[190D22]

The engine temperature goes down once I start driving. Someones it climbs up to that 100C mark... but only when I do a lot of stopping and going in the city.

Can I adjust the lifter myself or have an independant mechanic do it? What would it cost? Thanks.

[The Warden]

Are the 2.2l's lifters hydraulic? If so, I'm not sure anything can be done short of replacing 'em. If they're solid, it shouldn't be too horribly hard to adjust the valves yourself...

And the overheating definitely sounds like a bad fan clutch (I'm assuming the "main" fan's belt driven). You might want to try and turn the engine fan with the engine off...it should turn with some resistance; if it freewheels very easily, the clutch's definitely bad. Also, does the electric fan turn on when it's supposed to?

[190D22]

The big fan turns very easily, the wind blows it when I have the hood open if that gives you an idea of how easy it spins. The electric fan runs when the AC's on and when the engine gets hot. It's not overheating, it doesn't even come close to the danger zone, but I don't like this much fluxuation and I don't like it to climb that high at idle.

I have no idea about the lifters. The engine runs great, and it doesn't click all the time, and it's only at idle speed and anywhere between to 1500 from time to time... So I don't know.

Are fan clutches expensive? Is it a job I can do myself or w/ someone else that is mechanically inclined?

Thanks for the help.

[The Warden]

On a Benz, I'm not sure. A buddy of mine has an '89 Ford Bronco; I helped him do it himself; it was a pretty easy job.

I'll bet you money your fan clutch's dead. If it's spinning that easily...it should feel like you're trying to spin it but a fairly thick oil's keeping it from going (which is actually just about how the clutch works; as it gets warmer the fluid gets more viscous and makes the fan connect better to the shaft).

On the lifters, again, I'm not 100% sure...probably better for someone with more direct experience with these engines to step in here. But if the valves are adjustable, I'd start there...if they're hydraulic, it's probably okay to leave it at that unless the clicking gets noticeably worse...

Just some thoughts...good luck! Again, I don't know on Benzes, but on my Ford diesels, the fan clutch bolts are a left hand thread. I guess they were worried about the engine spinning the fan so fast as to make the bolts undo themselves...kinda like quite a few older vehicles that have left hand threads on the driver's side tire lugs...in fact, my van has left hand threads on the driver's side rear wheel...

[JimSmith]

190D22,

You may have an electric clutch on your car, which gets its signal from one of the thermostat housing sensors. If the sensor dies the fan clutch never gets a signal to engage. Or the clutch itself can go bad.

The fact that the temperature goes down when air runs through the radiator (highway speeds make enough ram air go through the radiator that the fan is not necessary to pull air through) is an indication the rest of the system is working ok. So, you most likely have a bad clutch or thermal sensor. How do the electrically driven fans work? They also run off sensors in the thermostat housing. They should come on around 105 degrees Celsius.

Hope some of this helps, but I know from reading threads here that changes in operating temperature trends can be frunstrating to fix. Good luck, Jim

[190D22]

The electric fan on the front of the radiator works fine, comes on around 105 and cycles w/ the AC running as it should. I have never once seen or heard the big fan run. But I either have the windows down or that AC running on max with the music up loud enough to be heard clearly, so I wouldn't probably hear it if it were indeed working. Is there a way to test to see if it works? Such as applying voltage to a switch on the fan. Where would you start to trouble shoot with this?

[JimSmith]

190D22,

If you have an electrically operated clutch for the main fan, the fan will spin freely when the clutch is disengaged, and then it will spin in direct proportion to engine speed.

If you notice the electric fan turning on at about 105 degrees Celsius then you should try popping the hood and looking to see if the main fan is roaring. It engages and disengages on my 1986 190E 2.3-16 with an audible click. And the fan makes a significant roar from beating the air as it draws it across the radiator.

On my 190E 2.3-16 it is "normal" and the car has always exhibited this tendency, to heat up at idle. It used to scare me as my older Diesels never flinched on the temperature gage - 175 degrees Fahrenheit on the old 220D, and 80 degrees Celsius on the 240D's, regardless of load, ambient temperature, city, stop and go, highway driving, etc.

I can look up the specs on the temperature sensors on my car, but you should confirm what kind of clutch you have and how it is activated. Maybe someone reading these posts knows for sure what the clutch mechanism is for your car. A viscous clutch will have some drag so it rotates at something like 1200 rpm max (varies with engine speed somewhat) until the clutch engages. Then the fan speed varies with engine speed to about 3200 rpm max, when the clutch basically can no longer handle the torque load of the fan and the fan speed tops out regardless of how much higher the engine turns.

Well, good luck and I hope some of this helps. Jim

edited for clarity

[190D22]

Hmm, so maybe the fan clutch isn't dead after all? If I do have an electronically controlled one. Is there a way I can force it to engage to make sure it does work fine? If it does, could it be a faulty sensor?

[JimSmith]

190D22,

If your engine is a 601 series, it appears from my W124 manual (note this is not a W201 manual, and it does not specifically address the 2.2 liter 4 cylinder Diesel in your car, but it says it covers 601 series engines, in specific the 2.5 liter turbocharged units for these cars) that it has an electrically controlled magnetic clutch. It is normal for these to spin freely. At 100 degrees C a thermostat housing sensor, called S25/1, that has two electrical connections on it, sends a signal to the fan housing via a plug off the top of the water pump bearing housing. I think you can force it to engage by either unplugging it, or by unplugging it and shorting out the two connectors in the plug, as the switch inside is either on or off and it can be send the signal by either connecting the two or not.

Hope this helps, Jim

[190D22]

Hey thanks. I will mess with it tomorrow and see. yeah my engine is the 601. The 2.5 liter turbo is the 603, and the non turbo 5 cylinder I believe is the 602. The 60x series are the newer breed which I prefer.

[JimSmith]

190D22,

I just read my previous post, and want to make it clear you should pull the plug off the S25/1 sensor and that will either make the clutch engage, or you short the two plug sockets together with a piece of wire to give it the opposite signal. One of those two should make it run. Good luck, Jim

[190D22]

Yeah I got that. Thanks again!