Everything you ever wanted to know about the Cummins 53 Block:
What is the "53" block?
The "53" comes from a casting number on the side of the block and is used to identify the problem blocks. Supposedly it affects about 100,000 blocks, but not only in Dodge Rams. Here is information regarding the castings from a thread on TDR:
1. Brazilian Blocks are cast by a company named "TUPY" and are marked such. They are identified with cast evolution numbers. #53's are TUPY's. #54 and later evolutions were improved to correct the block issues that the 53's had.
2. Mexican Blocks were made by "Teksid" these blocks to my knowledge never had a problem with cracking, as they are heavier duty by trait, but they did follow the evolutions and got thicker. These blocks do not have the 2 digit "cast number" embossed on the side, instead a series of numbers that are unidentifiable to me. The Mexican blocks were rumored to even be harder to machine do to a harder cast overall, basically better quality in my opinion.
Brazilian Tupys always seem to outnumber Mexican blocks during the ISB's production probably about 8 to 1. So basically if there is a pattern number its Brazilian, if there is a series of small numbers its Mexican.
The Mexican equivalent of a 56 pattern was the Heaviest ISB block of all. This means if you have a 2002 without a #56 on it and instead it has a series of numbers that are smaller and hard to identify, you got the the big boy!!!
Why the Worry?
Simply, the worry is that the block will crack. These blocks have thinner water jacket walls than other blocks so with coolant cavitation, corrosion, coolant pressure in the block, and torque, they may crack, spilling your coolant. I know from experience that it will not blow up the engine, but you will see that temp gauge rise more often than you'd like.
Who Should Worry?
Those owners of a
Cummins 24v ISB engine in a
1998-2001 model year vehicle. This does not only affect Dodge Rams. The 53 block was also used in medium duty trucks from different manufacturers, mobile homes, public school buses and mass transportation buses.
Recent information received from a 1998 12v owner says that some late 12v engines have "53" blocks. This owner knows because he HAS one. His truck has a build date of 11-97. He did say, however, that he has had no problems with his block, regularly pulling heavy trailers in the Rocky Mountains.
How Do I Find out?
If you want to see if your engine block could be one of these dreaded "53" blocks, crawl under the front, left side, and look up at the block on the front, directly under the injector pump (by the PS pump). You should see a large wiring harness mounted to the block. Directly below this, just above where the oil pan meets the block you will look for a "53" cast in the block. The numbers will be about 1 inch tall. I have heard of some cases where the "53" is elsewhere on the block, but I have not been able to verify any other locations or see them.
What Happens?
A crack develops on the right side of the engine, below the freeze plugs, right where the block bends back towards the inside of the block. It is a difficult area to see for auto transmission owners as it is directly behind the transmission heat exchanger. At first everything evaporates so there is no spot under the truck, but you may notice a coolant odor. The leak doesn't occur at idle in most cases because the crack is tight to get through, and doesn't leak until the RPMs of the engine are up, with the water pump causing higher pressure inside the engine block due to the restriction of the thermostat.
The crack will grow over time and you will go through coolant faster. I found that I lost coolant at a slower rate if I let the engine warm up for a while, so the thermostat opened and lessened the pressure inside the engine block.
When Might It Happen?
This crack begins when towing in most cases. I have seen modded trucks that did not leak until they were stressed from towing heavy loads in the mountains. These same trucks would put in several runs at the drag strip on a regular basis and never had a problem, even towing, until they towed in the mountains.
What Do I Do If I Have A Cracked Block?
This depends on a lot of things. In the first scenario, you have a stone-stock truck with less than 100K, and is less than 5 years old. In this case, just take it to the Dodge dealer and let them put a new short or long block in (they will decide which they put in), free of charge. If you don't have any other problems with the internals of your engine you might ask them if they will just replace the block with the latest design ISB block, the "Storm" design.
If you have no engine mods, but have added gauges or upgraded the transmission in a manner that is evident to the naked eye, you will likely get some flack from Dodge about your "mods", even though they don't really affect the engine's running or what caused the crack.
The dealer may try to tell you they have never seen a block crack. It's a bold faced LIE! Unless the dealer just opened it's doors or they don't have Dodge trucks in that area, someone there knows all about it, and the Dodge regional rep who must inspect the engine to approve warranty service on the block, due to its cost, knows all about it.
The Cummins engine is actually purchased from Cummins by Dodge with no warranty, and Dodge honors all warranty on the engine.
There is a current class action settlement that owners of these engines are entitled to participate in. Unfortunately, the settlement amount is only $500 per owner, hardly enough to replace the block! A company called 'locknstitch' has a method to repair these blocks that has proven somewhat successful:
LOCK-N-STITCH Inc. homepage: Cast iron crack repair, cast iron welding, thread repair inserts
The easiest way to remedy this problem however is to be aware that it exists and avoid trucks with a 53 block unless it's an extremely good deal.
