Short Engine vs. Long Engine

My 2004 Mazda 3 (83K miles) has a hole in the 3rd cylinder. I took my car to the Mazda Dealership as I was still under extended warranty. They were able to get the extended warranty company to replace my short block (at first they only wanted to do the rings).

They tried to get Mazda to cover the rest of the engine but to no avail.

My question is should I only replace the short block or should I do the whole shebang. Total cost is 7K but I would be charged 2400 of that. I have heard with replacing the short engine and not the long engine you may run into troubles with pressures etc.


I would go for the long block if you can afford it. A complete new engine is always preferable to a partly new engine.

While it’s better to have a long block, I have trouble understanding how that would be an extra $2,400. As an alternative, have them do the short block and have the old head sent out for a valve job and inspection, that should be much less than $2,400. Only if a problem is found with that head would you need to replace it.

The only differance between a short block and a long block basically is the head… A short block is ONLY the lower end of the motor (Block, pistons, rings, crankshaft, oil pump, etc)… A long block is all of that plus new head, cam shaft, followers (on a OHC motor), timing chain (or belt depending on the motor), etc… Ask what it would cost to have your old head rebuilt, it should be much less (around $250-$350 depending what they do to it)…

Maybe. Getting a new short block put in and having the head doen is more labor than getting a new long block installed primarily because of setting up the valve timing and valvetrain. And then theres the added cost of the chain/belt, the sprockets, and misc. For someone having the work done, it may be better to just go with the long block.

I agree, TSMB, but $2,400? Wow!

Yeah, I agree on that point. That’s high.

Wait mountainbike, A short-block does require all the setup labor of a long. Just not the new parts. He already can get the short done. It makes no sense to say that it is a lot more setup and labor to do the long block. Reassembling a short block is just as much labor just missing the head check and a few new parts assuming the old parts are not fine for another 75k. Not being critical just puzzled. I find it nearly as much labor to put on the old heads and realign the valve timing. Popping in a couple of new pieces on the head is an hour maybe more labor on the top.

For reasons I don’t understand, dealer service departments do things differently than I would have them done. I had a 1990 Ford Aerostar with the 4.0 V-6 engine. I bought it from an independent dealer, but it still had factory warranty. The engine would run roughly for about 30 seconds when it was first started. The problem was determined by the Ford dealer to be a leaking head gasket. Both head gaskets were replaced and the valves were ground at 22,000 miles. A year later, the problem was back. The heads were removed and it was determined that one of the heads had a crack. The dealer claimed that enough coolant had leaked into one of the cylinders and had scored the cylinder wall. The engine block and the cracked cylinder head were replaced, but the other cylinder head was installed on the new short block. I would have thought that replacing the entire engine would have been easier. However, I had no trouble from that point on.

There’s a little fuzziness to this; at least to me. Is the 2400 what you will pay if a long block is installed or will you pay 2400 of the bill no matter if it’s a short or long block? Just wanted to clarify that before going off on a tangent. :slight_smile:

If the engine is trashed because of oil starvation then there would be some concern over the existing cylinder head as to damaged cam lobes or journals, damaged cam journal saddles in the head, etc, etc.
Of course if this is an oil starvation problem without being caused by a mechanical failure then one wonders why warranty is paying for any of it.

A hole in the 3rd cylinder, what is that? The piston has a hole in it? The cylinder is scored? A crack or hole is allowing water into the cylinder?

If there is no damage to the head(s) then a short block properly installed should last just as long as a long block. Either way stuff like AC compressor, alternator, power steering pump, intake manifolds, exhaust manifolds will all get transferred from your current engine onto your new engine. A long block would come with new head(s) installed along with all the camshafts and valve train.

Without knowing exactly what happened to your motor, it seems a “hole in a cylinder” should only involve the parts of the motor which a new short block would replace.

Mechanics and service managers at dealerships are often amazed at the details of warranty work. If I were going that deeply into the engine I would rebuild it myself. But having the old head cleaned up and the valves ground and sitting it on a factory short block seems acceptable to me. A shop mechanic can install the head and timing system as well as a technician in a rebuilding factory.

I’m also curious about the hole in a piston.

Your car is worth the investment of the long block. Having factory work done is better than having dealer work done.

That factory work comes with a warranty which puts the dealer on your side for warranty work. You don’t want them working against you. Remember the human side of things.

With only 83K on the engine I’d opt for the short block. If there’s a problem after the short block is installed let the extended warranty cover the cost to make it right.

Total cost is 7 K (parts and labor)
The extended warranty will cover 4600 (short block + labor)
I would have to pay the different to get the Long Block
Mazda won’t cover the long block because of the age of my car and that I am over 70K. I am working with them to see if I can get the 2400 lowered so I can just replace the whole engine.
When I took the car in, the oil was down 3.5 liters (It was leaking internally)

Eureale, you understood me backwards. I said a shortblock, combined with removing and sending the head out ofor machining and then rebukding it, requires more work than installing a longblock…

TSMB - that’s my thought, too, a lot simpler just to swap out the long block, so where the $2,400 coming from?

I don’t see where the dealer is planning to do any head work, just swap out the shortblock. I’m not sure, but doesn’t this engine have the cams directly on top of the valves, if so, I would really be concerned about oil starvation damaging the cam lobes and the tappets (buckets).

If those surfaces are damaged, or valves ground or replaced, then it is a time consuming job to adjust the valve lash. I think in this case a long block would be justified. If you end up just doing the shortblock, at least get a new timing belt.

Good point keith. I just assumed the head would be done. Replacing a short block on an engine with a holy cylinder (wherever the hole is) and just swapping the heads out just isn’t i my frame of reference. I can’t conceive of any shop doing that. I cannot imagine any scenerio wherein serious damage would be done to a cylinder and there’d not be a serious concern about the heads too.

In short, I guess I can’t conceive of anyone changing a short block and just swapping the heads over. I just ain’t right.

It ain’t right, but that don’t mean that it isn’t done.