Yes I have the dreaded "53 block". Although I don't plan on doing major modifications I am curious to know if any precautions should be taken. It would make sense that if you keep these motors running cooler you should have a better chance of not having the failure. I'm thinking a 160 degree fail safe thermostat. What else could I do to help keep it from cracking?

 

actually from what Ive read its not the tempature per say that causes them to crack. its the rapid heating of a cold block that can cause 53 blocks to crack. best way to keep them from cracking is to let the motor come up to operating temps prior to hauling heavy or driving hard with it, EX: not start it up and go driving down the road at 30 lbs of boost and full throttle.

Im not sure if having a colder t-stat will help it or not. I dont see it hurting anything either.
However, despite their reputation, less than 1 % of all 53 blocks crack. matter of fact, I have 3 "53" block trucks in my family, not one has cracked and 2 of them are modifiedto a good extent past stock levels

 

what were the years for the 53 blocks?

 

The best advice I can offer is don't warm the engine up too quickly as said above. The 53 block is mostly found in '98 and '99 24 valve engines, I've heard rumors they have been found in '00 and '01 trucks as well. Try google searching "Cummins 53 block"

 

53 Block FAQ and Information

keep in mind, there were several casting numbers, best way to find out yours is to do what the article says and located the casting number, its an inch tall, not hard to find

 

if it is a 53 block it will be staring right at you on the bottom drivers side of the block, but there are 98-00 trucks that dont have the 53 block. the 53 block came from south america but there are 2 others 54 55 blocks that were made in mexico during the same time. and they do not have a casting number on the block. the 53 was the only one with a casting number. keep in mind though that the 54 55 blocks are very rare in the 98-99 trucks but they are out there.

 

Thanks guys, I understand I should not warm it up too quick, not add too many mods, nor get it too hot. But there is one constant variable that is bothering me and that is pulling heavy trailers up hill. So what can I do to keep coolant pressure low even under a load?

 

I think it's a hit and miss with the 53 casting. I got one out of a school bus with 300k on it with no cracks. I have another buddy who has one and beats the crap out of it! he just turns the key and drives off with his foot to the floor. He has 260k on his and no cracks. I've seen a lot of 53's with high K's and no cracks.

I've only seen one with a crack.

 

mods dont seem to affect the 53 block in terms of cracking, ive seen heavily modified 53 blocks pushing 800 hp and no cracks, I personally have only seen one 53 block crack, it was in a stock truck at it did so at 85,000 miles. if its gonna crack, most will crack before 100,000. if you want to put ur mind at ease, pull the freeze plug between cylinders 3 and 4 and use a digital dial caliper to measure the block thickness, according to research, only those with .253 thickness and thinner crack, .254 and its good to go.

 

As the post said above with the 53 blocks only having it casted in the block my 02 has inch tall 55 casted on the passenger side of block so i think 55 blocks have it casted on there also but i wanted to see what mine was after seeing this thread so i went and looked and it was there..