Bad Engine Block?

[budbud7]

I thought I had a problem with my oil pressure sender. While researching the net on that issue, I found something that, in my opinion, will make that oil sensor a minor thing. Have anyone here heard about "#53" cast into the 5.9 engine blocks? What I read was that if your block had that number your block was made in Brazil and it had a flaw in the block. Part of the block was too thin in certain areas and will develop a crack which will eventually totally fail. Well today I found that number on my block!

I have own that bus about 3 years and have topped off the coolant about 3 times but I have not found a leak anywhere. I looked the best I could today and didn't find a crack. Have any skoolie on here had to deal with that problem?

[SolomonEagle]

I had a Dodge with a 53 block. After driving the crap out of it, my buddy put the engine in a different truck and has been running around town for over 10 years with no problem. If its cracked enough to lose oil pressure you would likely know about it in my opinion. There are some different theories on how to fix it. I personally would just drive it until it drops, which it might never do, and just address the problem at that time. A different problem..I know that in the Dodge trucks the lift pump was inadequate and would often fail eventually wiping out the injection pump. An aftermarket unit and fuel pressure gauge or warning light is highly recommended and those trucks, I don't know buses have the same problem.

[o1marc]

Originally Posted by budbud7

I thought I had a problem with my oil pressure sender. While researching the net on that issue, I found something that, in my opinion, will make that oil sensor a minor thing. Have anyone here heard about "#53" cast into the 5.9 engine blocks? What I read was that if your block had that number your block was made in Brazil and it had a flaw in the block. Part of the block was too thin in certain areas and will develop a crack which will eventually totally fail. Well today I found that number on my block!

I have own that bus about 3 years and have topped off the coolant about 3 times but I have not found a leak anywhere. I looked the best I could today and didn't find a crack. Have any skoolie on here had to deal with that problem?

As I undertsnd it it is not a devastating failure. Some use sealers to keep it from leaking until a proper repair can be made. They crack right under the freeze plug under the horizontal sharp edge.

Cummins' Fatal Flaws - Diesel Power Magazine

[budbud7]

I don't have any service info on the bus nor do I know the actual miles. the odometer shows 37K miles and my guess its actually 137K miles. I don't have unlimited funds so I will kinda rethink on my plans on a full conversion. I really want an 8.3 RE Thomas. Perhaps I can wait until I find one and really do the conversion I want. I could replace the 5.9 with a 8.3 but I think that will bankrupt me. Perhaps its best to buy a bus.

Doom and gloom might not be in my future. The 5.9 might not ever fail.

[budbud7]

Originally Posted by o1marc

As I undertsnd it it is not a devastating failure. Some use sealers to keep it from leaking until a proper repair can be made. They crack right under the freeze plug under the horizontal sharp edge.

Cummins' Fatal Flaws - Diesel Power Magazine

That's one of the pictures that I saw. Some say any fix is only temporary, the block will fail.

[SolomonEagle]

If it cracks, any fix will likelly be temporary, agreed. It may run perfect for another 500k and never crack though too. Just sayin'!)

[Booyah45828]

"53" blocks aren't an issue in school bus service. Pickup trucks have the engine mounts on the side of the block, which with repeated flexing will cause the crack to form above it. Most medium duty units have a different design mounting system where the mounts are off the front of the engine and the flywheel housing, so no flexing and no cracking.

The only repair of a 53 block crack that I saw that lasted is the lock-n-stitch method. Google it if you want more info.

The lift pump on the trucks is the same on the buses, and is even more inadequate in bus service due to the tank location. Luckily though, if the pump fails to run, the pcm will sense low amperage on the circuit and activate the check engine light. That's a nice little feature that isn't available on the pickups. It doesn't show low fuel pressure though from a weak lift pump, which can trash the injection pump just as quickly.

Best bet is to upgrade the fuel pump to a better design and add in a fuel pressure gauge.

[2kool4skool]

208,000mi. on our 53 block,all's well.

[budbud7]

Originally Posted by Booyah45828

"53" blocks aren't an issue in school bus service. Pickup trucks have the engine mounts on the side of the block, which with repeated flexing will cause the crack to form above it. Most medium duty units have a different design mounting system where the mounts are off the front of the engine and the flywheel housing, so no flexing and no cracking.

The only repair of a 53 block crack that I saw that lasted is the lock-n-stitch method. Google it if you want more info.

The lift pump on the trucks is the same on the buses, and is even more inadequate in bus service due to the tank location. Luckily though, if the pump fails to run, the pcm will sense low amperage on the circuit and activate the check engine light. That's a nice little feature that isn't available on the pickups. It doesn't show low fuel pressure though from a weak lift pump, which can trash the injection pump just as quickly.

Best bet is to upgrade the fuel pump to a better design and add in a fuel pressure gauge.

Is the lift pump located in the fuel tank or on the frame rail?

[Booyah45828]

Neither place. On 98-02 they were located on the drivers side of the engine block above the starter motor.