I just found out about the "53 block" and I have one. Does anyone know what the odds are that it will crack? It has 180,000 miles now and the person who had it before me used it to pull fifth wheel and goose neck trailers. It seems to have been well taken care of and is still fine. Should I be worried?

This will probably help you out a bunch, if you haven't already seen it. http://www.stamey.info/Truck/Cummins53BlockFAQ.htm I don't know what that link says but I know a lot of people say the 53 block has issues only with those trying to pull the moon closer to the earth. If you pull sane loads supposedly it is fine.

I know a little about expansion and contraction and turning your block heater on I think is about the best you can do. I would turn it on with a timer about 4 hr. before you start up in the morning. And if your worried about after a load, I would plug it in then also.If the block ever cracks your in big doo then. The BS about the lock -n- stich is just that. It can be welded,but there's not a shop I can think of that would take the time and do it right because if they did it wouldnt be worth fixin.I checked into this a while back, because you can find a ton of low mileage 53 blocks:lmao:

I thought I did enough research before I bought it, but I learn more all the time. Most of which is thanks to everyone here

As far as my reading goes, the 53 blocks crack at a higher rate than others... less than 1% of 8 million reportedly crack but it's more than others & always the same place. Some 53s have made very high HP & held up, while other stock trucks have cracked. One theory is uneven heating, thus the idea of warming up before applying load & gradual cool down. Apparently the blocks were used in random order over a number of years too.Eventually I got in the correct place underneath to read mine is a 56. Best wishes,Russ

I just found out about the "53 block" and I have one. Does anyone know what the odds are that it will crack? It has 180,000 miles now and the person who had it before me used it to pull fifth wheel and goose neck trailers. It seems to have been well taken care of and is still fine. Should I be worried?

Mine cracked at 425k pulling heavy loads(i bought the truck with 70k) cummins told me(for what is worth) was from vibration(ever feel a 24V,it's like ultra sound) anyway NEW block from frieghtliner $1500.

From what i know some never crack and leak coolant,even people who have 500 hp and beat on them.It is from thin casting.If it bothers you there companys that make a coolant bypass,the system acts as a pressure relief for the coolant.This may help maybe not but it is worth checking into.imho

From what i know some never crack and leak coolant,even people who have 500 hp and beat on them.It is from thin casting.If it bothers you there companys that make a coolant bypass,the system acts as a pressure relief for the coolant.This may help maybe not but it is worth checking into.imho

Where would I find info on the coolant bypass system?

I have a 53 block. I beat on it every day. I run it hot. I run it cold. I don't do anything special.

I bought mine used with 300k on the clock no cracks. still going strong another 75k later, and I know the prev couple owners put her through her paces long before I got her, she still drives like a dream.cummins did offer a 150k mile warranty on the block, which you are just a tad over on. but the claim rate was as posted earlier 1%

Where would I find info on the coolant bypass system?

http://www.puredieselpower.com/catalog/9402-cummins-cooling-kitimproves-coolant-flow-cylinder-p-1374.html This one is a factory cummins unit. http://www.dieselpowerproducts.com/p-5290-wicked-diesel-coolant-bypass-985-07-59l-dodge-cummins.aspx I dont know much about this one,you would have to research it. I have opies kit.