I'm making a new thread on engine diagnosis for my 2004 D2, since I probably confused everyone with my build thread in this subforum. I do appreciate the help from everyone who's posted.

Here's the basics:
The motor was overheated several times by the PO, the shop he was taking it to did head gaskets (HG), along with decking the heads. Then they replaced just about all of the coolant lines, then the dude overheated again and shop owner diagnosed as HG again and said there probably isn't enough material left on the heads to deck them again (but he didn't take apart). Please note I'm not sure how many miles were between the HG job and the last failure.

You can tell the HG are leaking, because I can see them bubbling on the outer edges between the block and head. Also, if you drive around enough to let the car warm up it will overheat. I think the overheating is from combustion pressure stopping coolant flow, but I'm not sure. The radiator also leaks a bit from the drivers side plastic end tanks.

It has the following MIL codes:
P1300
P0305 Cylinder 5 Misfire Detected
P0307 Cylinder 5 Misfire Detected

Pending codes (these were stored prior to me resetting them for another read):
P0300 Random/Multiple Cylinder Misfire Detected
P0305 and P0307 (these were showing twice the first time I saw them, now they are in stored and pending)

When I drive the car the CEL flashes.

Mechanically, it doesn't sound too bad. I think a lot of what is going on is misfires. There is a definite belt/pulley squeal that drowns out a lot. But I can't really hear anything that makes me super worried. There is a strong smell of fuel in the exhaust, but I suppose if it is misfiring, unburned fuel would definitely cause that. There's also a weird water sloshing sound under the dash, does this mean the heater core isn't filled? So bizarre.

As I wrote in my other thread, I'm going to try to fix the LR motor, unless it would be better to replace. Trying to do this cheaply, planning to do all work myself. I think the best bet at this point is to do the HG job along with whatever needs to be done with the HG.

Things I will replace in the first go around, assuming there are no show stoppers (such as warped heads):

1. HG kit
2. Head studs (if I do discover something terrible with this motor after these are installed, can I remove them and keep for use in another motor since ARP studs are reusable?)
3. Spark plugs and 8mm wires
4. Water pump
5. 180F "thermostat"
6. serpentine belt
7. Radiator (If I can confirm the radiator is leaking, I'm not 100% sure)

 

Make sure that the block has not slipped the #5 liner or have a crack in #5. I hate to say it, but #5 has been known to crack. I have heard it from people on this forum and my LR mechanic. On the upside though, I have not heard of an 04 slip a liner (I think they fixed it on 04). I may be wrong on that so someone please correct me. Get the block pressure tested.
Good luck.

 

Is it possible to pressure test the block if the HG are not intact? Is this something done after the heads are removed?

 

04's are just as prone to dropped sleeves and cracks in the block.

 

I have seen pressure tests done with the heads on. But that is usually to see if there is a leak somewhere other than the block/heads. Test the block by itself (no heads). If the liner has slipped or the block has cracked, the test will show the same results with the heads on. That is why in your specific case, you should test your engine block by itself.
But before you test the block, try changing the plug and wire with cylinder #1. If you get a misfire on cylinder #1, then your in luck. You might just need a gasket change with new plugs and wires. The overheating could be the leaking radiator too because when they get clogged, they start to leak (that is what happened to me).

 

Try squeezing the upper radiator hose closed between the intake manifold neck and the tee where it branches into the radiator and tstat. Doing so for a few moments when cold will force all the flow through the heater core. If the coolant level drops, add and repeat. You may be air locking.

 

I forgot about that. Rtonder has a good point; there might be air in the cooling system.