Cranks but Doesn't start...

[mmaestrelli]

Hi all

First of all sorry if I'm posting it on the wrong section...

I need some help...

Going on holidays with my 2006 Pathfinder Diesel (yd25) same as D40 Navaras... Driving normally 100km/h ish and suddenly I heard a noise and I thought that would be the turbo pipe had disconnected from the turbo, drove another 2km in order to find a safe place to stop and fix it... (wife was on the driver seat) stopped on a servo and opened the hood, I saw the turbo pipes were connected but there was steam/ smoke coming from the left side... re started the engine and couldn't see anything wrong and the noise has gone away.. I jumped into the Driver's seat and wife pointed me the temp gauge was too high.. immediately turned off the engine and saw the radiator water was very low.... filled the radiator and saw there was a lick in the hose that's connected to the oil filter radiator... had to remove the wheel and the inner wheel wing to fix it... anyways got the hose fixed started the car and everything seemd good to go... went to the toiled to clean myself as I was covered in oil and dirty, went back and the car wouldn't start again.... spent about 2h trying to start it up, tried to pump / primer the diesel filter, tried some WD40 in the intake, checked all the fuses, tried to disconnect reconnect the battery, tried pump reset, checked the glow plugs etc.... and absolutely nothing!!!! It cranks up and there is normal smoke coming through the exhaust pipe so it's not a fuel system issue.... so decided to open the radiator cap and there was a lot o pressure on it..... closed it again had a few more cranks, opened it gain and pressure was built up.. let it opened and cranked it and I can see water jumping out of the radiator, the oild looks ok no signal of water either on the oil nor the radiator so I'm really suspecting the head gasket has gone, but lately she's been a bit hard to start anyways was thinking of re do the glow plugs but I did them about 3 years ago..... could someone confirm the blown head gasket symptoms or if there is something else I can try? Also any idea how much a gasket replacement would cost in Sydney?

 

[Old.Tony]

Certainly sounds like the head gasket is leaking out to the water jacket. There are a couple of things you can do to see if it is the gasket.

1) Dry compression test. You're looking for one cylinder to return a lower pressure than the others.

2) Wet compression test (same as dry, but you add a small amount (say 10ml) of oil to the cylinder before cranking). This test will identify a damaged bore or seized/damaged rings (which, if all of the cylinders provide similar pressures, means your head gasket is probably not damaged).

3) Test the coolant for the presence of exhaust gas contamination. This may cost some $ because the analysis equipment isn't cheap.

There are several possible fixes.

Cheapest: use an additive like Goss Chemiweld (silicate based) or Penrite Block & Cylinder Head Seal (ceramic fibre based). A slightly dearer (but cheaper than a mechanic) is Nulon Permanent Head Gasket Repair (kevlar based). I have NOT tried any of these, I chose to replace the head on my engine.

Middle-of-the-road: replace the head gasket and hope that was all it was. The heads are alloy, not iron, so they can (and do) crack.

Slightly Expensive: get an inexpensive replacement head. They even come fully assembled (with camshafts, valves and shims in place) and all the necessary other parts (gaskets, head bolts etc). This is the option I chose, it should cost around $1200-$1400 for the head, and maybe up to $2000 for the mechanic's efforts. Consider replacing timing chains and tensioners at this point. Note: my head was replaced about 30,000km ago and I have not had a single issue with it.

Donation to Makoto Uchida (CEO of Nissan): buy a genuine Nissan head (I think they were about $5K with no valves, shims, cams or even gaskets). Add maybe another $1000 (to Nissan) for the rest of the bits you need, then pay the mechanic as well. I am not certain of these figures, the conversation about this was a couple of years ago and we just recoiled at the prices they were asking.

Another option is a replacement motor. You'll find that most cars that are driving around on the roads and being written off aren't crashing because their engines had failed. If you can get a similar engine from a wreck you might save some $$, but remember to register the "new" fuel injectors in the ECU.