LOL what year do you live in?

__________________
CENSORED due to not family friendly words

Doesn’t really matter. Speed limit is the limit, slower traffic stays right.

Resistance is roughly cubic relationship, so the difference between 55 and 75 mph might be only 1.36x more speed, but 2.5x more power.

Diesels like to be heavier loaded, but it does relate to more time at temperature and more vibration instances that can fatigue or slowly loosen items.

NOT saying 55 should be the rule, unless perhaps the gearing of a 240d creates too much NVH. And the engines are designed for longer term at higher power.

But there’s something to be said for taking it easy too...

__________________
Current Diesels:
1981 240D (73K)
1982 300CD (169k)
1985 190D (169k)
1991 350SD (113k)
1991 350SD (206k)
1991 300D (228k)
1993 300SD (291k)
1993 300D 2.5T (338k)
1996 Dodge Ram CTD (442k)
1996 Dodge Ram CTD (265k)

Past Diesels:
1983 300D (228K)
1985 300D (233K)

It matters quite a bit when you're impeding traffic with your 55mph rolling road block and even semi trucks have to go around you. If your entitled piece of junk can't keep up with traffic it's time get off the road before you kill somebody. This isn't 1983.

ARTICLE 2. Other Speed Laws [22400 - 22413] ( Article 2 enacted by Stats. 1959, Ch. 3. )
22400.
(a) No person shall drive upon a highway at such a slow speed as to impede or block the normal and reasonable movement of traffic unless the reduced speed is necessary for safe operation because of a grade.

__________________
CENSORED due to not family friendly words

This is an old car with lots of miles, no service history and a driver with minimal mechanical skills. If making time is the goal, book an airline flight.

Will it make the trip at 80 MPH? No one can say for sure but the power train is more likely to suffer a failure at higher load / RPM.

Interstate and turnpike roads sometimes post a minimum speed. What is the min posted speed that you have seen? I've seen 55 for a 70 rated road.

As for keeping up with traffic. I've been on beltway / ring roads where the speed limit was 70 and cars are flying by at 90+ as they weave in and out across 4 lanes. Should I be keeping up with traffic at 90+ as well?

If the cars going 90+ were weaving through 4 lanes to stay at 90 mph, they are speeding. If all cars are going 90+, then that is the speed of traffic.

__________________
Milan Brown 1979 240D, rebuilt OM617.952 turbo diesel, rebuilt 722.315 transmission (my only daily driver)

Instagram: @maximed93

You know it’s funny. People often cite Europeans as having more requisite driver training and skill requirement, and as their cars and roads being the gold standard for speed.

Yet, go on those roads and amongst the fast cars and all that, is rapid speed limit onset and changes, and, caravans from Eastern Europe with limits of 60/80/100 km/h. These max speeds are clearly displayed by sticker on the rear bumper. And there’s no issue.

Yet here we chest thump about speed limits being too low and chest thump (here of all places) about low speed cars being unsafe.

SJW/EJWs making their stake by going the limit or lower in the left lane is an issue. It’s unsafe. Oblivious people getting passed on the right is an issue. People blasting past the flow of traffic, claiming it is too slow, is unsafe.

Staying right and within the posted limits (I’ve generally seen 40 min) is fine so long as they are alert and stay right. If the flow of traffic is 70-72, some statistically significant portion of travelers should be going 55-65. If the posted limit is 70, and the bulk of traffic is going 90, Id argue 30% over is a bit excessive, and they are not only on the hook for massively liability, but should expect to see trucks and governed vehicles, at least doing 72-73 max. And even that is unsafe.


Funny you state 1983 but cite a law from 1959. None of these concepts are new.

And if we’re talking entitled... pot, meet kettle. After all, you’re making the case to be entitled to go whatever speed you wish amidst a legally set limit.

__________________
Current Diesels:
1981 240D (73K)
1982 300CD (169k)
1985 190D (169k)
1991 350SD (113k)
1991 350SD (206k)
1991 300D (228k)
1993 300SD (291k)
1993 300D 2.5T (338k)
1996 Dodge Ram CTD (442k)
1996 Dodge Ram CTD (265k)

Past Diesels:
1983 300D (228K)
1985 300D (233K)

Taking it slow might be good within reason. Then again, I had no trouble driving my 1968 W110 200D fintail at 70-80 MPH for hours on end. It was happy to keep that speed range between Washington and Utah. And this is with an engine that had over half a million miles on it.

Now that I have a 1980 W116 300SD? Those speeds are nothing and I've even let it cruise at 100 MPH where the speed limit is 90 MPH and traffic is flowing faster.

Obviously, knowing your car is key, as is not being a cheapskate and waiting until parts fail to replace them. But, failures can still happen. It's a risk we all take. I won't hold up traffic unless everyone else is driving like a maniac and going well over the posted speed, then I move over to the right. Not because I don't want to stress my car, but I feel speed limits are there for a reason and I don't want to be driving 20+ MPH over just to appease everyone else's recklessness.

I always laugh when I see people driving their old diesel Mercedes super slow. I think, "The accelerator pedal moves down farther than you think!"

__________________
Stop paying for animal enslavement, cruelty, and slaughter. Save your health and the planet. Go vegan! I did 18 years ago. https://challenge22.com/

DON'T MESS WITH MY MERCEDES!


1967 W110 Universal Wagon, Euro, Turbo Diesel, Tail Fins, 4 Speed Manual Column Shift, A/C
1980 W116 300SD Turbo Diesel, DB479 Walnut Brown, Sunroof, Highly Optioned, 350,000+ Miles

Just drop in behind a semi and draft it, works great in the 240D.

If I ran 75 miles an hour in the 240D for more than an hour I would lose my mind. 7,700 miles would be nuts! AC on the comfy cruise speed is 63MPH, I hope the 300D has taller gears.

__________________
1981 240D Four on the floor, Orient Red over Parchment, bought with 154,000 but it's a daily driver and up to 180,000 miles, mostly original paint and all original interior.

I drove cross country in my 300D.

Car did very well . I had by that point done a lot of service on it. Though I had an issue where my brakes failed later that year.

Take a breath, have fun. Best car to drive in on long trips. If you're worried, get road side assistance so you can get towed to that Uhaul for a trailer and truck.

People saying to go slow don't drive in TN. I was passed while doing 80 in the 84SD. This is a car with an engine miss and rust but refurbished brakes and front suspension and cooling system. It will cruise all day at 80 mph and the temp gauge stays slightly above 80 C with air temps in the 90 F..

I check for fuel, oil and coolant leaks anytime the hood is up. There are none of significant size currently. I'll have it towed and get a rental car if it quits while on a trip. I only keep return line hose, belts & fuel filters. I don't consider belts necessary because They are kept relatively new but the old set get's dropped into the truck in case they are needed.

Go drive the car. A few Ben Franklins will fix any problem that comes up.

__________________
85SD 240K & stopped counting painted, putting bac together. 84SD 180,000. sold to a neighbor and member here but I forget his handle. The 84 is much improved from when I had it. 85TD beginning to repair to DD status. Lots of stuff to do.

I wonder if the OP planned out how many miles per day / how many driving hours.

That was pretty much my thinking. I love my 240D, and it scoots well. I’d drive it anywhere with confidence, but it would have to be slow. It’s just geared so it’s revving really high and thus fairly loud.

My 300cd has cruised at 75+ for hours. The 350SD obviously has no issues with anything, more modern engine and all

__________________
Current Diesels:
1981 240D (73K)
1982 300CD (169k)
1985 190D (169k)
1991 350SD (113k)
1991 350SD (206k)
1991 300D (228k)
1993 300SD (291k)
1993 300D 2.5T (338k)
1996 Dodge Ram CTD (442k)
1996 Dodge Ram CTD (265k)

Past Diesels:
1983 300D (228K)
1985 300D (233K)

I regularly take my 240 on 9 hour road trips at 75mph.
The only thing that’s ever stopped me was a small piece of plastic (clutch master cylinder pushrod) which I fixed with wire and gorilla tape.

__________________
1981 240D 4sp manual. Ivory White.

Ive been driving my 87 300d all over the place recently. From Sav to Chas twice a week. Clogged one fuel filter. Carry spares. You never know.

Interesting thread .

A Couple years ago I drove across Ameica in my 1982 240D, at that time the car had 300,000 + miles on it and #1 cylinder had maybe 200# compression due to a tulipped exhaust valve .

The tranny had never been rebuilt although I did keep it serviced and full of fresh ATF, it leaked a fair bit and I was adding "Trans-X" periodically .

It's an automatic so 60 ~ 65 MPH was the prudent speed, I used some oil and ATF but had a nice three week adventure that included some seriously steep hills in the Navajo Nation where I had to pin the throttle in first gear to keep it moving ~ it never got hot nor smoked one bit .

As mentioned, carry spare clear plastic fuel intake screens and always dose your fuel with fungus killer ! . if you keep on top of this, even getting a tank full of bad fuel won't spoil your trip nor cause any difficulties .

I tend to replace the v belts as soon as I see cracks in them and carry the spares in the trunk ~ the factory tool kit is comprehensive and I've used it to replace an alternator on the curb and adjust the other belts when I was 3,000 miles from home .

I imagine a four speed 240D would do 65 ~ 70 without over speeding the engine, every engine has it's sweet spot, find yours and stay in it, you'll do fine and have a nice comfortable and safe road trip .

Remember to check the spare for pressure and lack of visible belts ~ you never know how far you'll need to travel on the spare to lack of cracks and at least 35 PSI pressure is far more important than visible treads on an old, cracked & weather checked tire .

Make sure the jack works easily too .

__________________
-Nate
1982 240D 408,XXX miles
Ignorance is the mother of suspicion and fear is the father

I did then what I knew how to do ~ now that I know better I do better