So far cooling system AOK, might hit 101F today though!! - PeachParts Mercedes-Benz Forum

Oldwolf · #1 06-24-2010, 01:13 PM

How are your cooling systems working so far? I replaced my viscous clutch last year and so far so good.

With the A/C off temp never goes above 87 or so no matter how high the temperature is outside.

With the A/C on, and after accelerating in city traffic or going up a hill with my foot mashed down the temp temporarily might hit 95. But then it settles back to 87 after a few minutes of less strenuous driving.

Today it is supposed to each 101F here in Raleigh, so I’m really interested to see how my cooling system works on the way home today.

Jeremy5848 · #2 06-24-2010, 04:03 PM

Coastal northern California has not seen much in the way of heat yet this summer -- for example, as I keyboard this at Noon local time it's only 75F outside.

When we finally get some hot weather, I want to try driving the '87 on the freeway to get the engine good and warm, then get into (or simulate) city stop-and-go traffic with heat boiling up off the asphalt and the a/c on full. That will be a good test of the cooling system and I'm curious to see what the temperature gauge will say. Maybe I will finally get the engine hot enough to turn the aux fan on in high speed.

Jeremy

Oldwolf · #3 06-24-2010, 06:51 PM

Cruising down the interstate at 65mph the ambient thermometer read 101-102 F.

I had the Climate control set to 65F and AUTO so the climate fan was on high the whole way.

When I got up to speed (65 mph+) the engine temperature went up to about 90C and then settled around 87C. Once I got off the highway and stuck in traffic the temperature went up to 97C-98C. Then after accelerating up to 45 mph the temperature came down to 85C, lower than when cruising at 65 mph.

So far I am thinking the cooling system seems to be doing OK.

Jeremy5848 · #4 06-24-2010, 08:17 PM

Sounds like you have no cause for complaint.

bobodaclown · #5 06-24-2010, 08:33 PM

I'm pretty much seeing the same thing on my 92. Life is good.

Crazy_Nate · #6 06-24-2010, 08:38 PM

Quote:

Originally Posted by Oldwolf

Cruising down the interstate at 65mph the ambient thermometer read 101-102 F.

I had the Climate control set to 65F and AUTO so the climate fan was on high the whole way.

When I got up to speed (65 mph+) the engine temperature went up to about 90C and then settled around 87C. Once I got off the highway and stuck in traffic the temperature went up to 97C-98C. Then after accelerating up to 45 mph the temperature came down to 85C, lower than when cruising at 65 mph.

So far I am thinking the cooling system seems to be doing OK.

It was about that around here when I went home. 100-101 (yuk). I decided to see if my aux fan would come on (of all the times that I would need it, it would be now). No dice.

87-90C on the highway with the AC on full blast (R134... I'm not particularly happy with whomever converted it for me

), at stop lights and with light acceleration up to about 100C. Stop and go had it about 105C, at which point I'm on defrost with the windows rolled down.

I don't particularly use the AC often...I guess I need to fix some things...

vstech · #7 06-24-2010, 08:42 PM

Quote:

Originally Posted by Crazy_Nate

It was about that around here when I went home. 100-101 (yuk). I decided to see if my aux fan would come on (of all the times that I would need it, it would be now). No dice.

87-90C on the highway with the AC on full blast (R134... I'm not particularly happy with whomever converted it for me

), at stop lights and with light acceleration up to about 100C. Stop and go had it about 105C, at which point I'm on defrost with the windows rolled down.

I don't particularly use the AC often...I guess I need to fix some things...

DON'T PUT IT IN DEFROST TO COOL YOUR MOTOR FASTEST!!!
defrost brings in the a/c, so you are running heat and a/c in defrost mode!!!
put it to heat, and set it to economy!!!

Crazy_Nate · #8 06-24-2010, 10:29 PM

Quote:

Originally Posted by vstech

DON'T PUT IT IN DEFROST TO COOL YOUR MOTOR FASTEST!!!
defrost brings in the a/c, so you are running heat and a/c in defrost mode!!!
put it to heat, and set it to economy!!!

Yep, I tried that...but barely luke warm air came out of the vents

The temps stabilized, but didn't drop.

I can roast things with it on defrost, though. With the defrost on and some forward motion of the vehicle, it quickly dropped to below 95.

I think I may need a podectomy (?)

It's really only when I have the AC on and idling or accelerating...if I'm just cruising, the car is fine. If the AC is off...well, I haven't seen it over 90C.

latitude500 · #9 06-25-2010, 11:42 AM

I had the same problem with my 87 300 SDL, it would start t over heat (go past 80C) when I was in stop in go traffic or turned the ac on.

It turned out to be a fan clutch. I replaced it, and know my car sets at just a hair over 80C. When me setting in traffic with the A/C on full blast. Or 70 on the highway.

Your coolant system should be steady all the time.

jdh122 · #10 06-25-2010, 12:24 PM

Here in Houston (with outside temps peaking at around 95F) my '83 300D stays between 82C and, say, 87C or so, with AC set to around 75F on auto. It only creeps up to ~87C when stopped at a light after a high-speed run (50+). After a few minutes of moving it will drop back down to 82C or so.

This is with a recently flushed (one year ago) coolant system running Zerex G5 (50/50), new radiator, water pump, hoses, thermostat, expansion tank and cap and upgraded MB 7-blade plastic fan.

BrianCostello · #11 06-25-2010, 12:32 PM

I gave my 87 a good test a few weeks ago. It was 95 out high humidity. I was on the hwy going up a steep hill (top of hill is 1500 feet). I put the ac on high and the throttle to the floor

Temp gauge went up to 90-92, and settled right back to 85 once I let off the fuel.

Last year I replaced the viscous clutch, and this spring I discovered I needed a new aux fan resistor.

I would say everything is working fine.

Oldwolf · #12 06-25-2010, 12:44 PM

Quote:

Originally Posted by latitude500

I had the same problem with my 87 300 SDL, it would start t over heat (go past 80C) when I was in stop in go traffic or turned the ac on.

It turned out to be a fan clutch. I replaced it, and know my car sets at just a hair over 80C. When me setting in traffic with the A/C on full blast. Or 70 on the highway.

Your coolant system should be steady all the time.

Do you mean steady as in never moves?

Modern vehicles with computer controlled instrumentation have low pass filters so that the needle stays rock solid at some designed location so that normal temperature fluctuations don't upset drivers. Only when the engine hits another predetermined high temperature will the gauge start to rise.

I myself have thought it funny how the temperature in my newer cars never move once the engine heats up. It can be summer or winter and the gauge never moves from the same spot!

My MB doesn't have the filtering so I get to enjoy watching the temperature move around as the engine does different levels of work.

Could your needle be stuck or something if it is steady all the time?