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Hello Everyone!

I’ll be on the road driving for a 10 hour block of time in mostly 100-105F heat. Can’t do the drive at night. Recent service done and I have AAA. The drive will mostly be remote mountain country. Is there anything that I should do to the van to prepare? Will this drive have a significant impact on the life of my van? Can it take it? It only has 10k on it. I’ll only be stopping for gas and occasional pullovers to pee. I’ve got it set up as a cheapo campervan. So, I won’t have to interact with the world, except for gas pumps. Sorry if these are stupid questions.

thanks, La
 

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You don't need to do a thing. If you were hauling a heavy load on long grades in 105 might get higher coolant temps. What happens is your coolant control valve or thermostat will flow more coolant when it's hot.
 

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I hear you Lala. I am taking forever to insulate my van and I hate working the A/C so hard. I think highway cruising at that temperature is not a problem.

You might want to monitor your typical "base" temperature sensor reading --- mine centers around 90 C, pretty regardless of conditions. I never drive it very hard. Sometimes fast though ;)
 
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I live in southern Arizona and regularly drive my 2016 long stretches above 100 degrees with no problems. I have the standard AC and it has worked efficiently
 

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Discussion Starter · #5 ·
Thanks! You guys have me feeling more comfortable with this trip now. I normally plug my inergy kodiak aux battery system into the 12v outlet to power the fridge etc, but I won’t stress the system this time. There is plenty of power in the kodiak to keep things going for ~4days. So, I’ll just let it do its thing without the alternator keeping it charged.
 

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You should have nothing to worry about. I regularly tow 3500-4500lbs with my van. Up hill and down. In moderate to high heat, and occasionally in freezing temps. I watch my coolant temps like a hawk. I have never seen it budge past 90C. I do feel it get a tad sluggish in the heat with fans and full A/C, but nothing concerning and it still pulls the trailer fine. You should do just fine.
 

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Unlike most companies these days, Mercedes has the decency to include a real temperature gage. The gauge on most automobiles is designed to demonstrate that it is operating within perceived parameters within quite a range; the gauge on the mattress is actually an accurate temperature gage.

I have no reason to believe that your van will have any problems with the trip you are proposing. However the only advice that I would give that is unique to the situation is to keep an eye on that gauge. I don’t see any problem with you providing additional draw from the electrical system; this is a Mercedes-Benz not a Toyota. The vehicle is designed to operate within a wide range of
Conditions, the one you described being well within the parameters it’s designed for.
 

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I live in Phoenix and I've driven the van in 118F degree weather.
No issues!
A/C worked very well.
Just make sure you have plenty of coolant in your tank. I recently had to add some to mine.
 

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Hello Everyone!

I’ll be on the road driving for a 10 hour block of time in mostly 100-105F heat. Can’t do the drive at night. Recent service done and I have AAA. The drive will mostly be remote mountain country. Is there anything that I should do to the van to prepare? Will this drive have a significant impact on the life of my van? Can it take it? It only has 10k on it. I’ll only be stopping for gas and occasional pullovers to pee. I’ve got it set up as a cheapo campervan. So, I won’t have to interact with the world, except for gas pumps. Sorry if these are stupid questions.

thanks, La
No Metris experience but I have driven a number of cars in similar heat. In fact even higher from 107F to 111F to 116F even in one case 119F. I keep my cars in good condition. Generally before a long drive I have the engine oil changed and the car given a road worthiness inspection.

This inspection is a good idea, The tech checks under the car for any sign of a fluid leak and checks brake condition and tires. One time tech reported rear tires at wear bars and recommended I replace these before heading out. But I had a price quote for new tires at a dealer 2K miles away -- at my destination -- and I declined. Not but a few hundred miles away a rear tire picked up something and developed a leak. Took me two days and nearly 1K mile of extra driving to find a dealer with suitable tires. (Porsche 996 Turbo and one can't just fit any old tires on these cars.)

You do not want to set out with a "minor" coolant leak or a slow tire leak. The coolant resists boiling at temperatures above 212F -- in the case of one car in 116F ambient temperature the coolant temperature reached 226F and stayed there until I drove an hour or more and got out from the high ambient temperature area -- and a minor coolant leak can let pressure escape -- in one case this was a leaking coolant tank cap -- and the coolant can boil which can result in serious trouble.

The other thing you need to be aware of is on remote mountain roads there can be rock fall on the road. On one drive on 50 to Ely NV encountered small TV set sized rocks in the other lane. Hit one of those and you are stranded a long way from help.

The other thing to watch out for is animals. Open range can have livestock on the road. But a bad fence can have for instance horses on the road. Encountered a number of horses on the road on a drive to New Orleans.

Once in Wisconsin a bear ran out in front of my car. But most often a deer is what you'll see. And you do not want to hit one. On that drive on 50 just west of Ely a mule deer darted out from behind a guard rail. That impact ended my road trip. Also, turned out I was out of cell phone coverage. Finally got another driver to stop and he managed to call in the accident with 1 bar on his phone. Tow truck operator said he carries 3 different cell phones with the idea at least one has enough coverage.

Start with the vehicle in tip top shape. Carry extra oil, extra water both for engine (just in case) and for you to drink. Carry a good flashlight or 3. Out in the boonies the dark is amazing. A bright flash light in town turns into a flickering candle of light when used out in the boonies.

Carry snacks. And be equipped to spend hours, maybe over night, on the road if you have a break down. And at some times of the year it can get quite cold in the mountains.
 

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I have never understood the odd combination of pointless maintenance (changing oil before a long trip) and letting tires get to the wear bars (if you see the wear bars on tires, get to the next tire shop you come to and drop it off until they can order the tires- you should have changed them thousands of miles ago!).

Mercedes states thatthe temperature of their engine should not be of concern below 248F (120C). I’d guess that to be the boiling temperature of the antifreeze MB uses. A minor leak in the coolant system will NOT cause a major increase in temperature. That kind of temperature change that you are talking about applies to a rapid depressurization of the coolant system (that is, catastrophic failure). That sucks, but it also generally speaking doesn’t happen, and if it does it will not be the result of a minor leak already present.

The advice you are giving all applies to older cars with non-synthetic oil, direct fill radiators, and similar things that don’t generally exist any more. Actually the only overheating I have ever had on a MB product was the result of a failure of the auxiliary cooling fan, and that only effected the Car when it was sitting in traffic- open road even at 105 was fine.

This whole behavior dates back to when Ford and GM built cars that were equipped in base form with tires, cooling systems, suspensions, and other such that’s that weren’t actually fit for the purpose the car was likely to be used for. Not even GM does that anymore.
 

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You are misinformed.

The advice is good advice for any vehicle of any age really.

Not saying the oil should be changed when it is not due to be changed. Generally it just so happens when I venture out on a long road trip it just happens to be when the oil is due to be changed or right after. If it is due I get it changed before I leave. I have no desire to mid trip have to stop and get the car serviced.

A few times I have left town with the oil about half "gone" but when it was time -- based on miles -- to change the oil had it done mid trip. Once I tried to get it changed in Bend OR but the dealership had no techs they were out on vacation and training. So I drove south -- I was heading that way anyhow -- had the oil changed in Sacramento.

I can't recall doing this but if the oil is close to be due to be changed I'd do it "early" to avoid having to interrupt my trip to have the car serviced during the trip.

The tires just happened to be at the wear bars. I didn't purposely get them there before the trip. I knew from experience that when worn the tires wear slower and 2K miles was really doable. Plus as long as the weather was dry -- no rain -- the tires would be ok. But I overlooked the fact worn tires are more likely to pick up something which is what happened.

Really I should have listened to the tech and got new tires installed before I left.

The boiling point of coolant is not affected by anti-freeze. That is only responsible for well keeping the coolant from freezing (and its additives to prolonging the life of water pump seals and helping keep corrosion under control). The boiling point of coolant at sea level and at atmospheric pressure is 212F which of course is the boiling point of water which makes up half the coolant.

248F is a "safe" temperature, at least in the case of M-B vehicles because the cooling system can still maintain pressure at that temperature. It is pressure which raises the boiling point of coolant. I have seen 226F coolant temperature with one car and higher than that -- but not 248F -- with another car. Neither one suffered any from the elevated temperature.

But it is important -- and I stress this -- the system be pressure tight even when the coolant is very hot, over 212F. A good "test" of the cooling system is to ensure the coolant level is good -- but not too full or too low -- and then with the A/C off drive the vehicle around town until the coolant gets hot enough to trigger the radiator fan to run. Back home raise the RPMs to say 1K and hold until the radiator fan comes on. Then turn off the engine. The heat load of the engine will raise the temperature of the coolant even higher and this also causes the pressure in the cooling system to go up. If there is a leak even a small one it will make itself known.

If there is a pressure leak this can let hot coolant boil, flash to steam at the hotter areas of the engine. This boiling forms a steam pocket or bubble which blocks coolant flow over the hot surface which cause the steam bubble to form.

For what I'm talking about you can view this on the stove with a pan of water. Heat the water. As it gets hotter tiny bubbles form on the bottom of the pan. You can gently move the pan about and the movement of the water will dislodge the bubbles. But as the water gets hotter the bubbles form faster and get bigger. The pan needs to be moved with more vigor to dislodge the bubbles. At some point the pan must be moved quite vigorously to keep the water from boiling.

The same thing happens in the cooling system if the pressure is not maintained. The bubbles form and at first can be removed by the coolant flowing past. But at some point the bubbles form too fast become too big. Coolant is blocked.

This is an insidious problem as the coolant does not pick up the heat and thus does not reflect that localized overheating is taking place. Engine damage will result if this is not caught in time. The best way to "catch" this is to ensure it doesn't happen. Which is why I stress the cooling system must be pressure tight even when the coolant is at the maximum temperature the vehicle maker allows. In the case of M-B at least for some vehicles this is 248F.
 

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The boiling point of coolant is not affected by anti-freeze. That is only responsible for well keeping the coolant from freezing (and its additives to prolonging the life of water pump seals and helping keep corrosion under control). The boiling point of coolant at sea level and at atmospheric pressure is 212F which of course is the boiling point of water which makes up half the coolant.

Umm, no.
18018
 

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The chart shows the boiling point of coolant with a 50/50 mix is barely above 212F. The coolant will still boil and form the steam pockets that I mentioned if the pressure is not maintained. To get to say 248F boiling point the coolant would have to be a mix of 75% antifreeze and 25% water.
 

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I travel all over the country in my van. Here's all you need to do. Make sure your coolant is correct level, you can go over a little on your oil change, make sure you have enough. "I drove from SC to California last November and didn't check oil or anything else. Make sure your tires are inflated and have decent tread. That's about it...takes 5 minutes. Long distance travel is much easier on your van/car than city driving many times over. I'm heading to Colorado in two weeks. I just make sure my motorcycle is secure, and I have my scotch packed. That's about it.
 

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I travel all over the country in my van. Here's all you need to do. Make sure your coolant is correct level, you can go over a little on your oil change, make sure you have enough. "I drove from SC to California last November and didn't check oil or anything else. Make sure your tires are inflated and have decent tread. That's about it...takes 5 minutes. Long distance travel is much easier on your van/car than city driving many times over. I'm heading to Colorado in two weeks. I just make sure my motorcycle is secure, and I have my scotch packed. That's about it.
While you use your van a lot and on the highway not everyone gives his van the same usage.

The issue with heading out on a long trip with a van is the van may have spent considerable time running around town.

While the oil level looks good it is very possible the oil level is "good" because the oil has collected some water. In my experience with another vehicle after around 4K miles of usage -- some consisting of highway miles but in the dead of a MO winter -- the oil upon analyzing had 7% water. With the engine's total oil capacity at just over 9 quarts of oil the water represented around 1/2 quart of oil.

And no this was not coolant but water that had accumulated in the oil from the engine running.

So the scenario is the unsuspecting vehicle owner sets out on a long road trip. The engine and engine oil get hot enough to boil this water out of the oil. Now the oil level instead of being good could be low. Of course probably not low enough to trigger a low oil level warning. But the problem is the oil level is low. If the engine oil level was low to begin with but not low enough to prompt the owner to add oil, the oil level after this water boils away can be quite low.

There is some risk from running the oil level low even if the oil warning light doesn't come on.

So if the owner fails to check the oil level during the trip he makes the trip with the engine low on oil.

This is not good.

My recommendation is check the oil level -- all vital fluid levels -- before starting out on a trip. Then what I do is after every stop for fuel check the oil level after having filled the fuel tank. This check is done with the oil hot but the engine has been off long enough for the oil to return to the oil pan. Some car makers specifically recommend checking the oil after a fuel stop for the reason the oil is hot but will have time to have returned to the pan and the vehicle is pretty level when parked next to a gas pump.

I can't recall any specific time I found the oil level low but engines vary in their use of oil. Just because my experience with my vehicles is they do not use oil on a long drive -- provided I'm "cool" with the throttle -- doesn't mean everyone can expect this same outcome.

Also I advise before leaving the hotel to give the car a walk around. I did this once and spotted a small puddle of coolant. Turned out to be from a pinhole in the radiator.

Another time I stopped -- in the middle of the night -- at a rest stop for a rest. Afterwards I got out to walk and check the car. Spotted a low tire. (This before TPMS.) The tire had been low as when I felt the tread the edges had belt material exposed. The car had not manifested any signs of a low tire but I might have been too tired to really notice. At any rate hH\ad I not found this the tire could have suffered a blow out at freeway speed.

Long road trips are a lot of fun. One gets to see the country and I find the time on the road very relaxing. But to help ensure a trip free of bad events giving the vehicle a pre-drive check is pretty important. This should include checking the oil during the trip. An ounce of prevention...
 

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I know I can be snarky but I try not to be mean, but @Rockster are you some kind of idiot? I don’t check my car before long road trips because I check my car before ALL drives. The tires don’t go from acceptable tread to wear bars like badda Bing badda boom.

Wear bars aren’t a “it’s a good time to think about new tires” indicator, it is a “these tires should be replaced using a Delorean because it shoulda been done a long bloody time ago”. Tires should be replaced thousands of miles before you see the damned wear bars. To not do so is being dangerous- if you get in a wreck and your tires are that worn that would qualify as negligence.

Ethylene Glycol (aka antifreeze) extends the liquid state range of coolant substantially in both directions. It lowers freezing point and increases boiling point, which is, by the by, irrelevant. The reason you don’t want to drive your car with a coolant temperature much above 100C is that temperatures above that range imply combustion chamber heat soak potential that can warp the engines aluminum head, which believe me, is a lot more annoying than a bit of steam from your radiator.
 

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I know I can be snarky but I try not to be mean, but @Rockster are you some kind of idiot? I don’t check my car before long road trips because I check my car before ALL drives. The tires don’t go from acceptable tread to wear bars like badda Bing badda boom.

Wear bars aren’t a “it’s a good time to think about new tires” indicator, it is a “these tires should be replaced using a Delorean because it shoulda been done a long bloody time ago”. Tires should be replaced thousands of miles before you see the damned wear bars. To not do so is being dangerous- if you get in a wreck and your tires are that worn that would qualify as negligence.

Ethylene Glycol (aka antifreeze) extends the liquid state range of coolant substantially in both directions. It lowers freezing point and increases boiling point, which is, by the by, irrelevant. The reason you don’t want to drive your car with a coolant temperature much above 100C is that temperatures above that range imply combustion chamber heat soak potential that can warp the engines aluminum head, which believe me, is a lot more annoying than a bit of steam from your radiator.
Who's being the idiot? You check your vehicle all the time. And I likewise, on a trip or just using the vehicle around town. But not everyone does. And even if they check the oil level before the start of the trip that is no guarantee the oil level won't change.

My advice is intended to provide someone the least amount of risk of having an in this context a low oil level "event" during a trip. If someone reads my advice to check the oil level during the trip and decides that he doesn't need to bother with oil level checks during his trip that's his decision.

I've already admitted to a lapse in good judgement regarding the rear tires. While prior to that I managed to "nurse" worn tires some extra miles and got away with this time my luck ran out.

The rear tires on my Porsche cars lasted around 20K miles. They were fine -- barring the odd nail or two -- right down the bars. Of course I had a second car, sometimes another Porsche, with better tires that I drove when it rained. To replace these tires "thousands of miles" before I see the wear bars is an absurd bit of advice. In the dry the tires actually gripped even better worn -- nearly worn out -- than when new. Less tread to squirm when cornering.

And your knowledge of engine behavior at coolant temperatures "much above 212F" is severely wrong. With around 1 million miles of driving (a number of vehicles) over the years I have driven a number of cars with the engine coolant temperature above 212F and for hundreds of miles with no issues.

In fact it is rather a frequent event to park the car and shut off the engine with the coolant temperature above 212F, sometimes quite a bit higher, 216F or even higher still. Never had any issues from doing this. Given I keep the cooling system in good operating condition I wouldn't expect any.

As I stated the risk of engine damage from a cooling issue is present if the system fails to hold pressure. And this then can have the hot coolant (>212F) flash to steam at the hottest places in the engine, which is the head and more specifically around the exhaust port. If the coolant flashes to steam this can block coolant contact with the hot spot and localized overheating can occur. This can result in head warp or cracking or head gasket failure.
 

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Coolant does not flash to steam at 212F. It just doesn’t. Water does that, but not coolant. In fact the reason for antifreeze being standard in cars (it wasn’t prior to the advent of catalytic converters) is to accommodate modern engine temperatures on the high side.

Perhaps the biggest problem in this country today are ignorant people ejaculating their ignorance and then insisting upon it in places it doesn’t belong. You don’t know what the **** you are talking about; you run the risk of misinforming and endangering others. Kindly take your brand of horse picky and peddle it elsewhere.
 

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Coolant does not flash to steam at 212F. It just doesn’t. Water does that, but not coolant. In fact the reason for antifreeze being standard in cars (it wasn’t prior to the advent of catalytic converters) is to accommodate modern engine temperatures on the high side.

Perhaps the biggest problem in this country today are ignorant people ejaculating their ignorance and then insisting upon it in places it doesn’t belong. You don’t know what the **** you are talking about; you run the risk of misinforming and endangering others. Kindly take your brand of horse picky and peddle it elsewhere.
As your chart indicates coolant in a 50/50 blend ups the boiling point to a bit above 100C call it 105C and coolant will still boil if not under pressure. Granted not 100C but close enough. If the coolant is not 50/50 but something less as can be the case as the driver has added water to bring the level up then the boiling point is lower.

Do you really think that if the coolant temperature gauge is reading 212F that this temperature is uniform through out the engine and its cooling system? The areas around the exhaust valves/ports are much hotter. It is pressure that keeps the coolant that flows over these hotter spots and being subjected to much higher temperature from flashing to steam.
 

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Not all coolants are exactly the same, but this chart is for Ethylene Glycol, a common anti-freeze.

The lines represent the vapor pressure, i.e., the pressure at which the solution will boil at a given temperature (= the temperature at which it will boil at a given pressure).

The top line represents pure water which freezes at 0C and at 760 mmHg (14.5 psi, sea level) boils at 100C. At lower pressures (10,000 ft, ~10psi, 500 mmHg) it boils at 89.8C (Charles Darwin complained that at high altitude potatoes could boil all night but remained hard). The standard pressure cooker pressure of 15 psi gauge was determined by the United States Department of Agriculture in 1917. The internal pressure rises to about 30psi absolute (1550mmHg) so the boiling point is about 120C. The Metris pressure cap is about 20psig so ~35psia (1800mmHg) so the boiling point would be 125C for pure water with a good rad cap.

Adding 50% ethylene glycol shifts the curve down (or to the right) so at 1800mmHg the boiling temperature is elevated about 7C to about 132C. At the same time, the freezing point is lowered off the scale (<-30C).

So yes, adding ethylene glycol does both raise the boiling point and lower the freezing point, but it has a much greater effect on the freezing point (so we call it anti-freeze). What if we added more ethylene glycol, say 95%? Boiling point would now be off the chart (>150C) but strangely, the freezing point is now up to ~-20. Looks like 70% might be really good, but if the cooling system (thermostat) is regulating at 110C(?) there’s not much point. The thermal diffusivity does go up which would improve cooling, but the viscosity goes up even more so it’s harder to pump through the engine. (Prandtl Number at 100C for water ~2, 50% eth-gly ~7, 70% eth-gly 10.)

All great in theory, but the engineers appear to have worked it out over the years so just go by their recommendation. It’s still fun to try to see if we agree with them...
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