Injectors replaced and now a cracked head. Related?

[phonga]

Hi Guys,

I'm driving (was driving) an '06 D40 STX with about 170k on the clock. I was having serious problems with my truck going into Limp mode every couple of days. After taking it to 3 different places I was told it was either the fuel rail or the injectors and that it was impossible to tell which part was causing the problem.

After much deliberation I decided to spend the $3500 and replace the injectors.

The truck was running beautifully after the replacement. I'd forgotten how much power it had. I did have a slight problem in the mornings with it seeming hard to start and once it did kick over it spat some smoke for about 60secs each day. I called back the Diesel Mechanic and he said it was normal and the smoke was just excess fuel being burnt off. He said there was nothing to worry about but bring it in if I was worried. I thought I'd get through Xmas and take it back in Jan if I still had the problem.

Unfortunately, I don't have that option now as the engine overheated yesterday and left me stranded on the side of the Pacific Hwy. The temp gauge went through the roof and the coolant overflow tank was spitting all sorts of fluid.

My local NRMA guy came to save me and he said that I have definitely blown a gasket and with the amount of pressure build up in the overflow tank he would put money on a cracked head. He told me I might be better off replacing the engine. He said I'm looking at an $8000 - $10000 bill to get my truck back on the road (which I don't have!).

My question to all you guys out there is do you think the injectors being replaced incorrectly could lead to a blown gasket and possible cracked head? AND seeing as my existing engine has new injectors, am I better off replacing the engine or getting the existing one fixed?

I love my truck but after replacing the clutch, doing a uni joint, replacing the injectors and now needing a new engine the love affair is wearing thin. Great truck but I'm not sure I can afford to keep the thing on the road anymore.

 

[Old.Tony]

Welcome to the forum.

Sounds like a bad run of luck, but let's not go replacing the motor straight away. First things first - take some of the coolant from the radiator and have it tested for the presence of combustion gases. The NRMA guy might be right, but the test will either give you a positive diagnosis or point to a different problem (eg sticking thermostat, which is much cheaper to repair than a full rebuild!).

I wouldn't have thought that the injectors would cause a problem with the head gasket. Replacing the injectors + rail is simply following Nissan procedure, there are less expensive ways of doing that, just like you can pull the head down and replace the gasket yourself for much less $ than the shop's going to ask.

It may just be coincidence (if the head gasket HAS blown) that it's gone now, but the relatively inexpensive coolant testing will tell you which way you have to go next.

 

[phonga]

Thanks Old.Tony

I'll give it a go and see what happens. My father-in-law thinks he can replace the gasket if needed but I don't think he hasn't ever worked on such a modern engine. Are there any really tricky things we should be aware of?

I'm getting a bit ahead of myself, but now I've had time to get over the shock I'm looking forward to the idea of doing some of the work myself.

 

[Old.Tony]

Just make sure the timing chains and cams are marked for reassembly.

Oh, wait - actually, if you are going to rip the head off, there's a couple of things you can do to a motor this old (yes it costs a bit but it will be good for the motor):

1) Visit yd25.com.au, call them up and ask for Paul. Ask him for his replacement timing chain and fit that when it arrives.

2) Examine the glow plugs and seriously consider replacing them. Cheaper-than-dealer genuine equipment can be purchased through www.nizzbits.com.au (known on this forum as "Nizzbits" - you can send them a PM and ask directly).

You could take the opportunity to photograph the intake manifold and intake ports for people's education here too. Once you find the black gunk inside, you might contemplate doing two more modifications: EGR blank and catch can. Doing both will remove the source of that black gunk.

 

[nathand22]

The reason it was hard to start in the morning and then blew smoke was most likely due to water entering the cylinders.
I would not imagine it has anything to do with the injectors or there replacement.

Im sure you could replace the head and gasket for allot less the 8k.

As Tony said i would look into replacing the Timing chain while its apart, or at the very least do a thorough inspection of the chain and tensioners.

 

[phonga]

That makes a lot of sense. I was reading on here that Nissan charge a small fortune to replace timing chains. I'll start with the coolant test and go from there. I'll post the results tonight. Thanks so far guys.

 

[montana]

before you take the head or anything off block off both sides of the egr water cooler and try it, a few have leaked coolant and pressurised from exhaust.

 

[kevinm1962]

if you can do the job yourself it will be peanuts to fix but be prepared if your coolant comes back with chambers gasses at a guess the head will be cracked so new head as tony said do the timing chain catch can egr block about 3 grand max. nrma bloke is quoting Nissan prices jeez they quoted me 514 dollars to change front brake pads and machine discs.morons

 

[phonga]

So I took the advice and took a sample of coolant down to the local Natrad. They told me they needed the truck to be running to be able to do any tests. If it was running I wouldn't need a test. What to do now? I live in woolgoolga, about 25kms north of Coffs Harbour. Does anyone know where to get my coolant tested?

 

[Old.Tony]

I'll give the local radiator experts in Newcastle a call and talk to them about it. I smell bullshit from Natrad - if you have a read of this page (just the first result from Google, there were more) there are over-the-counter solutions for the test.

Interestingly, on that page they mention that the introduction of exhaust gas into the coolant changes the pH of the coolant. That means it's dead easy to test for.

Grab some identical coolant that would be in your radiator and using a digital pH meter, check its pH. Then check yours. If yours is more acidic it's contaminated.

I learned something new today. Today is a good day!

 

[tanz]

The thread you link to Old.Tony, and in particular the picture of the product in the third post, requires the vehicle running to draw the gasses out of the cooling system as suggested by the Natrad shop. I have the same product in our workshop, and it's a clear container containing the dye with a one way vent that you fit over the outlet on the cooling system whilst the engine is running (simplified explaination).

I read with interest about shops being able to carry out tests on coolant samples and have no doubt it can be done, but most workshops won't have the test equipment, as in reality they are in business to fix vehicles, not just diagnose the fault. Out of curiosity, I will check with our suppliers and see what test equipment is out there.

Cheers.

 

[phonga]

Thanks Old Tony I'll definitely give that a go. It's hard to know where to start sometimes