ZicZachZo

Ok, I have had it up to here with this car. It will run forever, but not without overhauling every part in the car.

Now, there are even more problems with my car. Not only does it have a wonderful rattle in the catalytic converter that won't go away... It also is now over heating around town. Nothing seems to be not working. All fans are going. Fluids are all fine. The temp dramatically rises to about 110 degrees celcius around town and above 60 it just settles back down to below 80. Any idea what that might be? The temp just shoots down on the freeway and then goes straight back up in town. I have no clue what it is because everything is working fine. Annnnd, I dont really know if it is overheating or not because it doesn't sound like it does when it really is really really hot.

Now, onto the next thing... There is a boiling sound coming from the top of my dash board tonight when i got out of the car. The heater had been on for about 30 minutes. I got scared and looked to see outside if anything was leaking from the car, but not a thing.

So, if any of you mb guys in the know can help out this poor pitiful soul, it would be greatly appreciated! THanks!

shadowgriffen

Have you checked for a soda can or anything metalic stuck to your converter? Sounds stupid I know, but I'm dead serious.

As far as overheating is concerned, how is your thermostat? Could very well be the culprit.

ZicZachZo

yes i checked the thermostat and it was fine. Nothing seemed to be wrong with it. I even bought a new one to see if it was crap and it was working better than the one I bought...

How do I go about checking to see what is in my cat??

yhliem

Could be a couple of causes for this:

1) Catalytic converters are surrounded by a heat shield that is 2 halves of very light gauge steel that are usually just crimped together. It's not inconceivable that the joints between the 2 halves have partially let go. (This has happened to mine) A couple of really large gearadjusted hose clamps works wonders.

2) As previously suggested (sort of) the rattle could be coming from one of the other heat shields (or something else) having somehow gotten bent or out of position and resting lightly against the exhaust somewhere.

3) An *internal* rattle could also indicate that the inner core of the cat has started to break down. There is no fix for this, just replace the cat.

In all cases, get the car up on a lift or jackstands and arm yourself witha flashlight and a light rubber mallet. Spend the time to inspect your exhaust system from header/manifold to tailpipe and determin exactly where the rattle is coming from. you'd be surprised how often a "rattle from the cat" is not from the cat at all.

You didn't specify which engine you have in your car, so the numbers that follow may not be exact for your car, but they'll be close enough. 110 is not overheating. it's running warm, for sure, but not overheating. Don't start panicking until your coolant temp needle starts hanging out in the red zone (~120 degrees Celcius)

Things to check in the cooling system:
1) thermostat - popping a replacement one into the thermostat housing and then running the car is not the greatest test in the world because you can't see what the thermostat is actually doing. I've gotten faulty t-stats out of the box before.

Best way to test is to submerge the t-stat into a bowl/pot of boiling water. You should be able to see it open fully. (The t-stat should start opening @ around 80 degrees C and be fully open @ around 87degrees C IIRC.) Otherwise you're just assuming that the replacement is good...and you know what happens when you assume...

2) temps that fans engage at - the engine fan should start at roughly 105 degrees and shut off when it gets to approx 95 degrees. the auxilliary fan should engage at about 115 degrees. If these conditions are not occurring you'll need to check your temperature sensors, circuit continuity (including fuses), and fan clutch operation.

3) condition of coolant - make sure the coolant is correct and in the correct ratio. If you are uncertain, then you'd be well advised to have the cooling system flushed and refilled. you should change the coolant every year in any case. If you had the coolant changed recently it's possible that there could be air trapped in the system. Where there is air, there isn't coolant and therefore there isn't cooling.

Something else that affects the engine temerature is the car's general state of tune. if the engine has to work harder it will heat up faster. Also, if the cat is clogged because it's falling apart internally this can, among other things, lead to higher operating temps.

incidentally, on an engine like the M102.983 (2.3-16v) the temperature regularly goes up to 105 in traffic. Mind you, this particular engine is designed to run a little on the warm side.

hmmmm...well...i've never come across this before so what follows are my best guesses. But first a little science:

The heating system draws its heat from the heated coolant via the heater core. The coolant mix combines the cooling properties of water with the high boiling point of (in most cases) glycol in order to deal with the levels of heat it is exposed to.

As the coolant draws heat from the engine it expands (basic thermodynamics). Because the cooling system is sealed, the expanding coolant is forced to maintain the same volume and actually preventing the liquid from boiling and effectively raising the boiling point even further.

Boilover occurs when the system can't shed the heat fast enough and the pressure that accumulates in the system exceeds the pressurization limits of the system. Usually the rad cap lets go at this point.

The bottom line is that the coolant boils (converts to a vapor) only if there's enough volume to allow it to: 1) because there's air trapped somewhere in the engine or 2) there's a leak in the system.

From your description, all I can think of is that maybe there is some air trapped in the heater core. This could have occured when the coolant was last replaced if the heater was not turned on with the fan set to high while new coolant was being filled into the engine.

ZicZachZo

First of all, wow I am so grateful for your plethora of information. It's almost too much to take in, so thank you so much.

I need to specify that my car is a 2.6L

My car has always been running at just below the 80 mark for as long as I can remember. Is that actually below meaning it's running in a sense cold?

yhliem

No problem. That's what we're all here for.

Well...it *is* possible (though unlikely, but stranger things have happened) that the gauge or the temp sensor (or both) could be faulty or inaccurate. Contrary to popular opinion the dashboard instrumentation in a car is not really intended to be super precise, but rather to serve as a reference for the operator so that he can monitor changes in the instrumentation rather than actual quantities.

As I said earlier, if you haven't changed your coolant in the last year of two, get it changed and have your cooling system flushed while you do. Also, havea look at the old coolant and make note of it's colour and if there are any impurities in it.

Have you noticed the smell of coolant in your car at all? Or that the windows seem to be fogging up faster/more than usual? Or perhaps that the low coolant light has been coming on lately?

There's a valve located under the leaf tray at the base of the windshield (it's ironically called the heater valve :p) that's made of plastic and has been known to fail on the W201s. It's not very expensive and pretty easy to re&re. You may want to look into the possibility that the heater valve is stuck and restricting the flow of coolant. This should not affect the operating temp, but you never know.

Based on your description of the symptoms I'm leaning towards vapor lock in the cooling system or an, as yet, undetected leak.

mctwin2kman

Could be a bad cap on the coolant tank. If it is not sealing properly and allowing air in you will get higher temps. The boiling sound leads me to this. You also need to Burp all the air out of the system on these cars, if there is air then you get boiling. The gurgling leads me to this one. Also is there fluid in the car, heater core going out....

yhliem

That's what I said. LOL

mctwin2kman

LOL! Mine was shorter though!

On a side note, my temp shot up to 115 the other day for some unknown reason, I went to pull over and turn off the engine and by the time I was to the side of the road my wife noticed the temp drop back down to 90. Damn T-Stat must have stuck closed and it is only 2 years old. No leaks or any of that crap either. I am not driving her as much since my wife lost her license and I get to finally drive the W203 so I am thinking since it sat for about a week that it just stuck. Oh well they are only 30 bucks or so, so I will have to get a new one. She must be pissed at me since she is running so good I have not had to wrench on her in a while. Temperamental b!tch.

yhliem

Well, I haven't got that much to say on the Rev anymore so I have to find somewhere else to be loquatious.

kepla

Most guys like to make the opposite boast !

I guess that if she has lost her license then you can expect her to be a little upset !
As regards the overheating problem, then it sounds like possibly a 'hidden' leak or an airlock in the system. If the car had been without a corrosion inhibitor in the coolant for a few years (it does happen !) then it is possible that the impeller blades in the water pump might have corroded so much that they no longer pump the water. Bear in mind that the youngest 190 is now over 12 years old, and the oldest over a quarter of a century !

mctwin2kman

New water pump, no air as I know how to burp it, and new radiator as well. New coolant with radiator change. It was a sticky thermostat as when it opened it cooled right back down quickly.

And the she in that post was the car not the wife. And yes the wife is upset but she got off easy for her stupidity and learned from the stupid *** mistake she made.

yhliem

Am I the only one who thinks that some elaboration/explanation is required?

mctwin2kman

Just something I have always done with machines. Boats, bikes, cars. Normally done when a woman is around to be a wise ***. 'She is one sexy beast! And the chick is not bad either!'

Probably not the best example but hopefully you get the drift. Not to mention cars are a lot like women, especially older ones(cars), they can be very temperamental and have quick mood swings!

yhliem

LMAO

I wasn't referring to your choice of pronoun, THAT I understand. I was interested in findinbg out what your wife had done. LOL

mctwin2kman

DUI! Funny part is we had a ride home and were there and fine. Then one of her dumbass friends calls cause her BF got a DUI and she had not had a drink in over 5 hours, we were at a Wine Tasting Festival. She thought she was fine and even I felt fine but she drove. We picked the friend up at the State Police Station and went back home to wait for the BF to be processed. About an hour or so. Then we went back to pick him up and it was dark and she went to turn in to the Station. Well being so dark and the signs that said do not enter being set way back she did not notice until the head lights hit then and just proceeded to enter anyhow since it would have looked much worse to swerve out and hit the actual entrance. Well she was getting a ticket for that when another officer walked by and said he smelled booze, even though she was talking to the one for quite a while and he smelled nothing. Well she was above the .8 legal limit barely and got busted. Funny part is that the friend who called originally was now below the limit and drove us all home anyway because her BAC was under .8. Sucks but lesson learned. All in all they toss the charges if you go through a bunch of stuff in PA and spend lots of money in fines and classes.