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My mechanic says a 6.5 never steams out the exhaust

I think its the air to fuel mixture ratio and combustion temperature (air going through gets hotter and stays hotter longer through the cycle). Idling very little fuel is burned and it pumps air through mostly heating it up some. Typically gas engines will condensate some moisture in tail pipe initially when starting cold but stays vapor when warmed up. I think a bit of H2O is a byproduct of combustion. The relatively fixed air to fuel ratio of gasoline systems just show the vapor more when temperatures and humidity are right.

In the winter time Diesel's will have some white smoke until temps rise some from cooler combustion might be some "steam" in there.
 
Yeah, would've helped to say that up front.
They will with a bad head gasket and coolant getting into the cylinder.

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That can happen also. It just depends on the exact failure.


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79jasper said:
That can happen also. It just depends on the exact failure.


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Click to expand...
Exactly. For the long division version...

They can, but dont usually progress to that point.

Usually compression will push the gases through the coolant system on a small crack area. The hot gases superheat the coolant not allowing the coolant to remove heat from the block and heads. Then the engine overheats.

During diagnostics the failure is easier to detect in a gasoline engine than diesel by the chemical test kit because the gasoline has a much quicker reaction with the test chemical along with the btu of gas vs diesel carried to the coolant through the gasses.

Also, most gas engines are less than 170 psi, while the 6.5 should be 380-400 psi. So remember that massive increase in pressure difference when trying to force gasses through the same size crack in comparison. A failure half the size in a diesel will transfer more than twice the heat to the coolant through the failure point.

When you get a larger crack or opening in the failure location the volume of coolant can be enough that during the 3 non compression strokes of the piston that there is a bit of coolant in the chamber that makes it's way out the exhaust.- so you need a "worse failure" to get steam out the exhaust than you do to push gases into the coolant. Also the intake stroke of a gas engine produces vacuum to assist sucking in the coolant during that stroke. Under turbo boost your 6.5 does not, there is always pressure in your system, not vacuum. The n/a 6.2 & 6.5 engines are more likely to steam when they have blown headgaskets.

Becasue of this the gas engine is more likely to have coolant make it way through a larger opening, fighting less cylinder pressure, to be turned into steam in the exhaust.

By the time you have enough coolant making its way into the exhaust system to be turned into steam, you dont have an engine that gets hot and overheats on its way to Grandmas house. It is overheated and puking coolant before you get to the freeway.

So it isn't that your mechanic is wrong in looking for other failure points first, he just hasn't seen it.
 
Probably should've started off saying you were told you have a head gasket leak or cracked head. Lol
I wouldn't use either of those. Fix it right.

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He's STILL beating that dead horse? Jeez, what does it take to understand that there is major damage and only one way to correct the problem and that way does NOT include magic tablets or miracle sealer cures?
 
People get leaks after r/r head gaskets! Engines use oil new from factory. GM used these tablets new from the factory. Machine shops over cut heads.... the 6.5 is not a holy relic that needs a red carpet treatment. My diesel guy who has a very successful bus in town says that the tablets work good. Mix in water add one or two at a time until it stops the leak. He reasoned. " Those work good he says." 4l80 e transmissions melt the cage that holds the overdrive roller clutch. Any reasonable stuff is worth playing with.
 
Neal, Its your truck -by all means try what you want.

But when you ask for opinions and options and the message yoh keep getting here is not doing it, dont be surprised when the 3rd time or more it's brought up someone responds sharply.

I have taken out rod, piston, lifter,pushrods, rocker on engines and turned 8 into 7 cylinders several times. Once turned a 351 windsor into a 5 cylinder. And they ran a long time after that- doesnt mean it was correct.
But it was the only $ option at the time.

If you are going to do it, please do. And please post all about it before, during, after so that the next person in the same boat can learn if thats the right call for them, good or bad results.

We just warned against what we have tried in the past and regretted, but by all means- brand y might be better than brand x I used. Give it a shot. If it works, great. If not, junkyard it- it is yours not ours. We just like to see more stay on the road the longest possible because we are a little on the fanatic side of these old things. And after posting here about the bandaid results if it doesnt work out, please dont go around bashing the 6.5 name any, thats all.
 
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