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Trooper Head Gasket Problem?

369 Views 12 Replies 2 Participants Last post by  truisuzu, 
T
Well... looks like my luck ran out.

I rebuilt my Trooper engine and all went well with first startup and break-in. It started immediately and had no codes or CEL, etc. The only visible issue was a very small coolant leak in the hidden valley between the heads.

When the common chamber is in place, you can only see down into the valley in one small area (see attached image). When looking down there, it showed as moisture around the only visible bolt head of the thermostat top pipe flange. The thermostat top pipe flange has a raised edge about 1/8" high. If there was any leak on the top of this flange... it would have to fill to a depth of 1/8" before it would run down into the valley. Every time I looked at this flange top, there was no coolant pooled... only moisture there.

As I use the Trooper (700+ miles so far) and then check down there, I see pooled coolant in the bottom of the visible valley section about 1/8" deep (there are raised dividers which separate the sections of the valley so coolant would have to fill up the section - about 1" deep - before it would spill over into the next section.). Because of the common chamber, I can't see what's happening in the rest of the valley. No hoses or pipes are leaking (that I can see) and there is no visible leaking on the outside of the engine or on the ground. I have been soaking up the pooled coolant that I can see with paper towels until I can remove the common chamber and get to the zone.

Today I went to town (about 35 miles away) and while there, the engine started running rough and the CEL came on flashing. Shortly after this, I could detect a smell. I checked under the hood and there were no visible leaks (except for the small leak in the valley). The engine was visibly running rough. I started to drive the Trooper home and as I accelerated up to speed, lots of whiteish smoke was coming out the tailpipe. I drove about 55-65 mph on the way and made it home.

Clearly, at least one of the head gaskets is leaking and coolant is being burned in the cylinders. The coolant leak in the valley may have been leaking from the outside of a head. My assembly was very clean and I used Fel-Pro head gaskets and the proper torqing procedure, etc. If I remove the common chamber, I don't know if I will be able to visibly detect where the leak is coming from and I don't know exactly how I will determine which head has the head gasket leak.

Any ideas are welcome!

Thanks very much!

Gas Circle Auto part Metal Fashion accessory
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T
I should also note that I watch the oil pressure and engine temp like a hawk and the engine has not ever overheated since I rebuilt the engine.

I have not re-torqued the head bolts since the engine re-assembly. Could they have loosened enough to allow coolant to leak past the head gasket?

Thanks!
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S
Did you inspect the heads and block decking during assembly?

Did you reuse the bolts or replace?

To identify what cylinder is burning coolant, you only need to look at the spark plugs. You will know it when you see the plug.
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T
Thanks very much for the ideas!

The block and heads were worked by the same machinist and I'll have to ask again what he did to the surfaces. But I'm sure he would have done whatever was required if they weren't true as I told him to do whatever it needed. I used new head bolts. I'll check the plugs tomorrow.

Thanks again.
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S
Did the machinist remove enough decking that you would need to use a extra thick head gasket?
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T
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I don't know about the amount removed during machining... haven't spoken with machinist yet. I didn't know you could get an extra thick gasket. The gasket used was a blue, Fel-Pro gasket... seemed thick enough. (I also have a set of black ITM head gaskets I didn't use).


OK, so I pulled out the plugs and they seemed fine except for cylinder #4. Plug was soaking wet and it smells like fuel. Did a comparison and smelled all the plugs and #4 reeks of fuel. I stuck my inspection camera into the cylinders and all looked normal except #4 which has a pool of liquid on top of the cylinder.

So I have a coolant leak in the valley and a pool of liquid in cylinder #4 which smells like fuel.

Is there some situation where fuel would end up pooled on top of the cylinder? Injector working but spark plug not firing?

Maybe I don't have a blown head gasket?

Thanks!

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T
Here's a pic of the heads before installation.

Thanks!
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truisuzu said:
I don't know about the amount removed during machining... haven't spoken with machinist yet. I didn't know you could get an extra thick gasket. The gasket used was a blue, Fel-Pro gasket... seemed thick enough. (I also have a set of black ITM head gaskets I didn't use).


OK, so I pulled out the plugs and they seemed fine except for cylinder #4. Plug was soaking wet and it smells like fuel. Did a comparison and smelled all the plugs and #4 reeks of fuel. I stuck my inspection camera into the cylinders and all looked normal except #4 which has a pool of liquid on top of the cylinder.

So I have a coolant leak in the valley and a pool of liquid in cylinder #4 which smells like fuel.

Is there some situation where fuel would end up pooled on top of the cylinder? Injector working but spark plug not firing?

Maybe I don't have a blown head gasket?

Thanks!

View attachment 129855

View attachment 129856
Click to expand...

Appears there is no evidence of a faulty head gasket at this time.
A compression test will verify this.

Fuel pooling in the cylinder can be caused by a ignition misfire, over fueling injector & low compression. First thing to do is check your oil level. excessive fuel finds its way into the oil pan raises the oil, dilutes your oil. causing your oil not to lubricate your engine.

Check for faulty injector by performing a injector drop test.
Check for low compression by performing a compression test.
If results are low, perform a leak down test to pin point the source of the loss.

The coolant in the valley can come from many location, Slim slim slim chance from a head gasket.
Pressureize the cooling system, grab a flash light, inspection mirror and have a look. You will spot the source.
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T
Thanks VERY much for the info!

Thankfully, the head gasket is not blown and the compression tested out at 135-140 psi across all cylinders. I will move on to the other tests and look for the valley leak.

Thanks again.
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T
OK, I have verified that the #4 cylinder coilpack and spark plug are sparking just fine. The coilpack 1-3 contacts show .2 ohms which is the same as the other coilpacks. When a spark plug is in the coilpack and the engine is spun with the starter... the spark plug sparks as it should.

Isn't the #4 fuel injector being faulty the only likely culprit for flooding the cylinder at this point? I haven't done the drop test yet as I am currently waiting on tools.

In my digital service manual... I can't find a specific section detailing the replacement of a fuel injector. Does the entire fuel rail and other injectors need to be lifted off of the common chamber to replace a single injector or is it possible to get a single injector out without disturbing the rail/other injectors?

Thanks!
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T
OK, I can see by looking at the top of the fuel injector that the rail must lift up at least a 1/2" for the top of the injector to be out of the rail so I guess all the injectors and the rail must be lifted up/out in order to replace a single injector.

Thanks!
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All injectors on that side of the engine needs to be lifest out of the intake manifold. Only the injector that is being replaced needs to be removed from the fuel rail. Some will remove all 6 injectors from the fuel rail to replace all the seals... some wont.
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T
Thanks for the info!

All the injectors are new with new seals (including the problem #4 injector). Sounds like lifting one side of injectors out of the intake won't disturb the other side too much.

As an aside, when I assembled... I didn't like the dirtyness I saw inside the fuel rail itself. At each injector location, I could see a small glimpse of the inside of the tube. There were black carbon-like deposits visible on some of the junctions. I cleaned, scraped, flushed, etc. I run o.nly premium gas in the Trooper so I was a bit surprised by this.

I inspected the electrical connection on the problem #4 injector and all looks pristine.

On the coolant leak, I was able to jam my inspection camera under the intake from the rear and get a fairly good view of the zone while I ran the engine only for a minute. This wasn't long enough for the engine to properly heat up but there was no sign of leaking at the pipe insertions or the two rubber hose connections during this short time. Still waiting on tools for a proper pressurization. We'll see where that leads.

Thanks again.
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