95 degrees C cruising on freeway w/ AC on - PeachParts Mercedes-Benz Forum

OlBrenner · #1 04-15-2008, 12:53 AM

This will be my first AZ summer with my 82 300D. Today was about 95 degrees F and cruising at 70 mph I notice I'm getting quite close to 100 degrees C on the temp gauge, I'd say 95 C. I usually hang out around 85-90. Keep in mind this is with my A/C cranking on high.

Those of you in the southwest, do you notice your cruising temps start to climb a hold a bit higher than usual in these temps? Should I start troubleshooting my cooling system now and avoid an overheat when it starts to really get hot?

Knightrider966 · #2 04-15-2008, 01:05 AM

Quote:

Originally Posted by OlBrenner

This will be my first AZ summer with my 82 300D. Today was about 95 degrees F and cruising at 70 mph I notice I'm getting quite close to 100 degrees C on the temp gauge, I'd say 95 C. I usually hang out around 85-90. Keep in mind this is with my A/C cranking on high.

Those of you in the southwest, do you notice your cruising temps start to climb a hold a bit higher than usual in these temps? Should I start troubleshooting my cooling system now and avoid an overheat when it starts to really get hot?

I drove to Cave Creek today and noticed my engine doing about 95* with the AC on full blast. I think your ok here. My car has never overheated on me and I just carry a couple jugs of water/coolant premix in the trunk for keeping the system topped off.

Today's high was 98*. I don't think this is a problem, really. Just make sure your hoses are in good shape and your fluids are full, especially now when it gets hot. Your engine will need all the care you can give it for our summers!

bustedbenz · #3 04-15-2008, 01:09 AM

Quote:

Originally Posted by Knightrider966

I drove to Cave Creek today and noticed my engine doing about 95* with the AC on full blast. I think your ok here. My car has never overheated on me and I just carry a couple jugs of water/coolant premix in the trunk for keeping the system topped off.

Today's high was 98*. I don't think this is a problem, really. Just make sure your hoses are in good shape and your fluids are full, especially now when it gets hot. Your engine will need all the care you can give it for our summers!

I agree, not likely to be a big problem. In addition to checking hoses and fluids, check your fan clutch.

I am fully aware that this not an issue when the car is moving through the air at 70 mph.

However, it WILL become an issue when you are stuck in traffic or sitting at lights or drive-thrus on these hot 100+ days.

Spin the fan with the engine off, but hot, on a hot day. If the fan free-wheels, your clutch is bad and will allow the car to overheat anytime it's sitting still. If the fan feels stiff to turn, and stops after a revolution or two, then it's working properly.

Knightrider966 · #4 04-15-2008, 01:11 AM

Quote:

Originally Posted by bustedbenz

I agree, not likely to be a big problem. In addition to checking hoses and fluids, check your fan clutch.

I am fully aware that this not an issue when the car is moving through the air at 70 mph.

However, it WILL become an issue when you are stuck in traffic or sitting at lights or drive-thrus on these hot 100+ days.

Spin the fan with the engine off, but hot, on a hot day. If the fan free-wheels, your clutch is bad and will allow the car to overheat anytime it's sitting still. If the fan feels stiff to turn, and stops after a revolution or two, then it's working properly.

Good point, I didn't think to mention the fan clutch! It's a good thing we have electric fans on these cars too, were going to need them from now untill Halloween!

bustedbenz · #5 04-15-2008, 01:17 AM

Quote:

Originally Posted by Knightrider966

Good point, I didn't think to mention the fan clutch! It's a good thing we have electric fans on these cars too, were going to need them from now untill Halloween!

I've never quite trusted the electric fan... seems like it's on the wrong side of the radiator to really be capable of moving air where air needs to be moved. Nonetheless, we rebuilt the motor in it last summer (replaced something that wore out in there, the brushes were fine but the bearing went out I think) - and it's ready to come in if the mechanical fan can't hold it. If I had to pick one or the other, I'd bet on the properly clutched (or solidly mounted) engine fan.

Knightrider966 · #6 04-15-2008, 01:21 AM

Quote:

Originally Posted by bustedbenz

I've never quite trusted the electric fan... seems like it's on the wrong side of the radiator to really be capable of moving air where air needs to be moved. Nonetheless, we rebuilt the motor in it last summer (replaced something that wore out in there, the brushes were fine but the bearing went out I think) - and it's ready to come in if the mechanical fan can't hold it. If I had to pick one or the other, I'd bet on the properly clutched (or solidly mounted) engine fan.

Oh me too, but it's nice to have this in there! I have a spare just in case!

jkoebel · #7 04-15-2008, 08:31 AM

I wish mine would sit at 95C with the A/C on during freeway driving. Mine sits at 105-110C with no A/C on the freeway, close to 115C with it on.

I've ordered a new radiator, we'll see how that helps.

OlBrenner · #8 04-15-2008, 10:24 PM

Quote:

Originally Posted by jkoebel

I wish mine would sit at 95C with the A/C on during freeway driving. Mine sits at 105-110C with no A/C on the freeway, close to 115C with it on.

I've ordered a new radiator, we'll see how that helps.

That doesn't sound good at all...

Bob Albrecht · #9 04-15-2008, 10:33 PM

Quote:

Originally Posted by jkoebel

I wish mine would sit at 95C with the A/C on during freeway driving. Mine sits at 105-110C with no A/C on the freeway, close to 115C with it on.

I've ordered a new radiator, we'll see how that helps.

It does sound like you needed a radiator. When this happened to me I also needed two electric fans.

Knightrider966 · #10 04-15-2008, 11:44 PM

I might remove my thermostate and see what happens. That is if I get bored enough!

jkoebel · #11 04-15-2008, 11:46 PM

Quote:

Originally Posted by Knightrider966

I might remove my thermostate and see what happens. That is if I get bored enough!

Won't help much...these cars use a bypass thermostat type design. Taking the thermostat out will not force all coolant through the radiator, best you might get is a random mix, worst is it won't cool anything quite correctly.

Thermostat installed and closed = all coolant through recirulation into engine block again. Open thermostat = all coolant into radiator. Or some fraction in between. With it out...you get "in between" at best.

vstech · #12 04-15-2008, 11:48 PM

Quote:

Originally Posted by Knightrider966

I might remove my thermostate and see what happens. That is if I get bored enough!

um, don't do that... the car needs it to properly circulate coolant...

Knightrider966 · #13 04-15-2008, 11:54 PM

Quote:

Originally Posted by Knightrider966

I might remove my thermostate and see what happens. That is if I get bored enough!

Just kidding! I'm not this bored!

OlBrenner · #14 04-15-2008, 11:55 PM

I won't remove it but I might want drill a few holes though it...

http://www.dieselgiant.com/thermostatreplacementandmodif.htm

rg2098 · #15 04-16-2008, 12:36 AM

Right before I put mine away for the winter, I took a long trip from Michigan to Kansas. On the way down I noticed the temp up to 100 / 105. Nothing seemed to change it (slowing down, speeding up, A/C, no A/C). For some reason it would randomly, literally drop right back down, and flutter a bit. I think my sensor is acting funny, and not the actual engine temp. You may have a similar issue.