Overheating w123 - Page 5 - PeachParts Mercedes-Benz Forum

funola · #61 05-07-2013, 06:53 AM

Quote:

Originally Posted by whunter

........ ,..................

Testing the fan clutch by hand, with the engine off will only show if it has a good / bad bearing.
The fan clutch requires thermal load on the bi-metal face to fully lock-up.

This can be risky on a car:
I have very carefully used a heat gun for testing the fan clutch with the engine off, IMO it works better (lower risk of melted plastic) with the fan/clutch assembly removed from the car (with the base locked in a vice).

.

how long a job is it to remove the fan clutch and are special tools needed? if you fashion an elbow for the heat gun ( aluminum foil with a hose clamp?), can it be used safely with the fan clutch in the car?

funola · #62 05-07-2013, 07:11 AM

Quote:

Originally Posted by digieditny

Yes thermostat was replaced.

Well they were close to the same temperature. I didn't write it down since it was close enough. I'll have to recheck it.

Would lack of flow cause the problems I'm experiencing?

I don't own a heat gun. There goes that idea...

did you put in a new thermostat? what brand and temp? there's a recent thread on an aftermarket thermostat that would run consistently 10 degrees hotter than as marked.

did you test thermostat in boiling water before installing?

please describe differences in symptoms running with and without the thermostat.

use your ir thermometer to check different parts of the radiator. it should be hottest at the top and get cooler as coolant flows towards the bottom.

funola · #63 05-07-2013, 07:19 AM

Quote:

Originally Posted by ROLLGUY

I just talked with my neighbor that has the car that we just replaced the head gasket on. He is still having the exact same problem you are describing, and I do mean EXACT!.
Fortunately I removed the bad condenser the other day, as we are going to install a parallel flow condenser. He (Wade) was feeling the temperature of the radiator (no condenser in the way), and he noticed that one side was cold, and the other was hot. We both suspect that half of the radiator is clogged (the cold side). That would make sense, as at highway speeds it starts to get hot, but cools down when the heater is turned on. The heater core is stripping off the heat that the clogged part of the radiator is failing to do. I have an extra (actually 3) turbo radiator, and will replace it soon. I will let you know if that fixed it. If so, I would bet you have the same problem....Rich

so after all it wasn't the head gasket? wow! did the machine shop pressure test the head? hope this does not turn out to be a mystery like your oil pan thread!

whunter · #64 05-07-2013, 07:50 AM

Quote:

Originally Posted by funola

how long a job is it to remove the fan clutch and are special tools needed? if you fashion an elbow for the heat gun ( aluminum foil with a hose clamp?), can it be used safely with the fan clutch in the car?

10 MM wrench.

Remove three of the four bolts holding the base to the water pump.
Loosen the fourth bolt enough to tilt / dismount the assembly.
Cautious angle / blade motion will slip the assembly out, without removing anything else.

.

ROLLGUY · #65 05-07-2013, 09:47 AM

Quote:

Originally Posted by funola

so after all it wasn't the head gasket? wow! did the machine shop pressure test the head? hope this does not turn out to be a mystery like your oil pan thread!

The head gasket was actually bad. I believe the clogged radiator caused the gasket to fail....Rich

digieditny · #66 05-07-2013, 11:29 AM

I used wahler (116 33017 087). I remember reading that some thermostats run hotter. The wahler was the correct one no?

The car warms up much faster now. That's really the only difference I noticed.

So is removing the fan clutch a quick job? I can't be working on my car for hours on the street. If it take 30mins to remove, that's fine. Sounds like a quick job if it's only 4 bolts. Are these bolts likely to fail like the thermostat housing bolts?

I'm going to order the heat gun. Is it showing bad form if I just replace the fan clutch with a new one? Should it be just part of maintenance to change it?

I will drive the car around sometime today and test again with my ir gun and give you guys exact temps.

SD300 · #67 05-07-2013, 11:49 AM

merc does need the thermostat, reason as there is a shunt allows water to recirculate when cold and thermostat not open,
thats the reason our T has 2 pieces, it looks like a valve at the end, is to block water to re-circulate when hot.
another reason is your rad is plugged or semi,
sometimes feel your hand down the rad fins when eng is****** not running!!!!
u may feel some are is still cold , reason as hot water is not passing thru the whole rad, only passing on selected area.
u need a new rad or try reverse flush a bit.

Quote:

Originally Posted by digieditny

Thanks Funola! How's it going?

Barry. Good idea. Will do that.

Diesel911. Yes the Aux fan does come on when the AC is turned on. The car overheats with or without the Aux fan.

I took out the thermostat completely to see if it'll overheat and it still does. So it's not the thermostat. Anyway I checked the thermostat.

I'm assuming that the temp and gauge are fine since the readings are accurate according to my ir gun.

Yes Ive heard of disasters because of collant flush. Will leave that as very last resort.

w123fanman. I dunno. This is what the haynes manual says for w123 1976-1985.

ROLLGUY · #68 05-07-2013, 12:17 PM

Quote:

Originally Posted by digieditny

I will drive the car around sometime today and test again with my ir gun and give you guys exact temps.

Please do, and check both sides of the radiator. If SD300 and I are correct, you will see one side colder than the other....Rich

digieditny · #69 05-07-2013, 03:50 PM

Ok here are the radiator temps. The car was at 85c.

Top driver's side 53.3
Bottom driver's side 52.3
Top passenger side 61.3
Bottom passenger side 46.5

How are these temps?

ROLLGUY · #70 05-07-2013, 09:56 PM

Quote:

Originally Posted by digieditny

Ok here are the radiator temps. The car was at 85c.

Top driver's side 53.3
Bottom driver's side 52.3
Top passenger side 61.3
Bottom passenger side 46.5

How are these temps?

I am not sure if those numbers would be the same for a known good radiator, but someone with an IR meter could tell you. On a side note, I just got finished with replacing the radiator in my neighbors (Wade) car, and I think it fixed the problem. The radiator feels cold all across the bottom, and hot at the top. This is after a hard drive down the highway. The temp gauge hovered around 100, and went up and down from there. It went about half way between 100 and the red mark, and that is when I stopped and felt the radiator. The engine did not feel overly hot, and nothing like it was boiling over. I am almost positive the old radiator was partly plugged. I will replace the thermostat anyway, just for good measure. I believe you have a plugged radiator based on my experience because of the same symptoms the cars are/were having...Rich

funola · #71 05-08-2013, 11:50 AM

Quote:

Originally Posted by ROLLGUY

The head gasket was actually bad. I believe the clogged radiator caused the gasket to fail....Rich

Did the new radiator fix the run hot problems?

From all I've read, these 617 engines (cast iron head/block) can take a lot of abuse as far as overheating and still be ok. They supposedly can run up to before the red line on the coolant temp gauge and still survive. Did your friend severely overheat his engine? What if you replaced the radiator first before replacing the head gasket? Maybe the head gasket was not necessary? I guess we will never know.

funola · #72 05-08-2013, 12:00 PM

Quote:

Originally Posted by digieditny

Ok here are the radiator temps. The car was at 85c.

Top driver's side 53.3
Bottom driver's side 52.3
Top passenger side 61.3
Bottom passenger side 46.5

How are these temps?

I don't know for sure if those numbers are normal but I have a feeling they are on the low side. Do the test again with the engine fully warmed up to 85C (driven under high load for 15 minutes), take the measurements again. The top radiator hose on the engine end (engine running) should be very close to the temp gauge (85C), top hose at the radiator should be a few degrees cooler. The radiator should get progressively cooler from top to bottom. To check if this is so, shut the engine off use your hands.

Your car was not overheating last summer when I fixed your fuel problems? Did it one day start to overheat all by itself or were there some other related incidence? Did you run low on coolant? Is it currently losing coolant?

digieditny · #73 05-08-2013, 12:17 PM

Hey Funola. I have a dentist appointment today so I'll drive the car hard on the way home and check the temps again. Ya the car has had overheating problems for about 2 years. I just drove the car with the heat on high with only the passenger vent open and the windows down. Sweating like a maniac. The coolant level is always the same. Not low. I don't lose coolant. I can't remember when the car started overheating. It just suddenly one day started.

There's a thread somewhere where I suspected it was a bad temp sender. I bought one but the readings I was getting from it were extremely low. I drove the car a bit with it on. A car next to me at a red light said I was losing coolant all over the road. So I pulled over, refilled it, waited till the car cooled, and drove it straight home. I suspect that I left the cap loose since it was not on properly when I pulled over.