Black smoke at idle after new head gasket

Laids · **Posted:** Thu Mar 20, 2014 7:26 pm

I decided to take the plunge and keep my CRD. I have owned since new but the last year I have been nursing it through a probable blown head gasket. I went to a recommended shop that works on a lot of diesel pick ups. I ordered all the parts through the advice of this forum, mostly ID Parts, timing belt kit, glow plugs, head gasket kit etc and ARP studs. The head was sent out and preasure tested, was ok so everything went back together.
Engine runs fine but when idling pours out black smoke. they sent out the injectors for testing, came back ok. I have been in contact with the shop but since it is about an hour and some away I am not seeing it myself. They tell me they have noticed the coolant resorvoir seems to build up pressure very quickly and shows steam. Also gets a lot of blow through the elephant hose pipe I have on. I know the egr is no good and I have had it unplugged for the last 3 years (lived with engine light on).
I think one possiblity is they didn't torque the ARP studs enough, I did give them the numbers that were on this forum.
Anyone have any thoughts what could be the problem? I don't even want to contemplate the amount I have into this project if there is something major wrong.

geordi · **Posted:** Thu Mar 20, 2014 7:58 pm

Pressure testing the head is a good first step, but did they also test to ensure the deck of the head was perfectly flat? A blown head gasket usually means that it had overheated (at least locally) and warped the head.

Also, did you measure the cylinder liner protrusion properly? There are 3 different sizes of gasket, and the differences are quite minor, but if the coolant bottle is immediately building pressure, then you have a massive problem from either the gasket size or warping.

Sorry that it hasn't worked out yet.

kissfan79 · **Posted:** Thu Mar 20, 2014 8:02 pm

Others with more knowledge will chime in but it is my understanding that if there is any kind of quick pressure build up in the coolant reservoir that it is an indication of a leaky head gasket. Considering you just had the job done....I wonder if one or more of the studs wasn't tightened done with enough torque.

Jim

kissfan79 · **Posted:** Thu Mar 20, 2014 8:03 pm

As I said...Geordi to the rescue! Sorry to hear about the issues after doing so much work and putting that amount of $$ into it.

Jim

Laids · **Posted:** Fri Mar 21, 2014 3:30 pm

I saw the head when it came back everything was good, 1 hole gasket was replaced with same. Too far down the road to turn back now.

Hexus · **Posted:** Fri Mar 21, 2014 3:47 pm

Laids wrote:

I saw the head when it came back everything was good, 1 hole gasket was replaced with same. Too far down the road to turn back now.

I think you just drove back to the beginning of the road and started over, to be honest.

flman · **Posted:** Fri Mar 21, 2014 4:42 pm

Laids wrote:

I saw the head when it came back everything was good, 1 hole gasket was replaced with same. Too far down the road to turn back now.

Sounds like you still have combustion leak by the way the pressure is building up?

But why would you have black smoke at idle, indicating a fuel rich condition? They say the injectors are OK? Could it be motor oil, although that should not cause black smoke? How about an air obstruction causing the rich mixture?

geordi · **Posted:** Fri Mar 21, 2014 8:33 pm

Black smoke is an obvious sign of loss of air somewhere. The pressure building in the coolant bottle is a BIG warning sign about the head gasket, it is possible they are two different problems however.

The black smoke could also be from a loose boost hose or from residual fuel in the cylinders from them trying to start it. That could take several minutes to burn off at idle.
But the pressure in the coolant bottle... Really can only be from the head gasket. Pressure / flow behind the CCV puck doesn't really indicate anything other than possibly valve blow-by from not sealing properly. The valve guides don't have any strong seals on them, so any normal cylinder pressure can leak past them if the valve seat isn't clean.

Sorry to say, despite your belief that you are "too far down the road" but you aren't. They didn't do something correctly on the job the first time, and they really need to take it ALL THE WAY back apart again and measure the liner protrusions - Did you or they order the correct gasket? If the liners weren't moved, the SAME gasket size (number of holes) could have been ordered, but measuring is the only way to be certain.

If the gasket is too thin, then the head might be impacting the top of the liners and the imperfections in clamping or iron-liner-to-aluminum-head differences in expansion could be causing the leak. If the gasket is too thick, the seal might be great... Until the combustion forces itself through the laminated layers of steel and you have a blown gasket again. This could (in theory) happen almost immediately, even on a cold engine.

Cylinder pressure is close to 500 psi BEFORE combustion, and peak cylinder pressure is LOTS more than that on every single cycle. If the gasket is compromised at all in any way... Pressure in the bottle / water leaks / water in the cylinder maybe / BENT RODS / blown engine...

It really is that simple. This needs to be completely re-done, or you are risking nothing less than the entire engine. Obviously something wasn't done to spec. There should NEVER NEVER be any pressure in the coolant bottle.

Sent from my iPad using Tapatalk HD

racertracer · **Posted:** Sat Mar 22, 2014 2:19 am

There is an old post about someone discovering a cylinder sleeve had moved, it slid. Can this really happen, can a sleeve slide up and down, or fail to stay secured in place becoming the cause of a leak?

Causes for exhaust gases into the cooling system are either a head gasket leak or a crack in a cylinder wall.

From a web search regarding causes for black smoke in a diesel engine:

Black smoke indicates poor and incomplete combustion of diesel fuel. There are many causes, including…

Incorrect timing

Dirty or worn injectors

Over-fueling

Faulty turbocharger (ie not enough air to match the fuel)

Incorrect valve clearance

Incorrect air/fuel ratio

Low cylinder compression (eg sticking piston rings or worn components)

Dirty air cleaner

Restricted induction system (eg system too small or kinked inlet piping)

Other engine tune factors

Poor quality fuel

Excessive carbon build up in combustion and exhaust spaces

Cool operating temperatures

flman · **Posted:** Sat Mar 22, 2014 8:40 am

X2, time to tear it back down and find what they did wrong or missed?

Black smoke at idle after new head gasket

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