Your Thoughts? Power Loss + White Exhaust

[Chester5000]

Summary

My mustang randomly has a huge loss in power, clunky acceleration, and rich white smoke from driver side exhaust.
White Exhaust

https://imgur.com/a/ZQlXUyp

I initially thought it was an injector, so I have injector cleaner in my gas tank. That's most likely why the right side is a little smokey. That, or it's the H pipe on the dual exhaust. I wish I could tell you whether or not it smells like super rich exhaust vs. exhaust with coolant, but I don't trust my nose there.

I recently had the radiator, thermostat, and hoses replaced. That came with a coolant flush and top up. Interestingly, leading up to this issue, I had a low coolant light come on (right after the replacement) leading me to think I was burning it. Unfortunately, I didn't visually see how much my reservoir had at the time of the radiator service, so I don't know where I started vs. where I was before adding more coolant when the light came on.

Considerations

• 
  
• Idle is "ok" even with slight acceleration in park, but when I took it for a half mile drive around the block, there was a cloud of white smoke behind me and the engine was chugging pretty bad.
• 
  
• Cylinder 5 piston has more gunk than the other 7 which are generally spotless. This is in line with the theory that bank 2 is where it's occurring (driver side exhaust). I inspected cylinders with a borescope during my leak-down tests.

What I've already tested/checked

• 
  
• Seafoam injector cleaner via gas tank
• New sparkplugs (while I was checking to see how the old ones looked - nothing too telling)
• Leak-down test (2x) - 85-90% pressure retained making me think it's not head gasket. I used a borescope to get all pistons to TDC before using a reputable leak down test kit. I was actually very surprised how well these tested... maybe too good? Did I do it wrong?
• Lower intake manifold gasket didn't appear to be the cause either, but I haven't installed the new one and put it back together yet. Up until this point, my theory was this gasket had a leak at the water jacket. See this video: Lower Intake Gasket Before Removal

  https://imgur.com/a/sU3jcU9

Theories

• "It can't be injectors since exhaust is white and not black."
• "it can't be head gasket because leak down test was good twice in a row."
• "It doesn't appear to be the lower intake manifold gasket due to it's in-tact appearance."

What do you think?
Thanks a ton in advance.

 

[RAU03MACH]

i would try a compression test on that side first one by one
do the other side after and compare
make sure the intake dose not have deep pits or gouges around water jackets and channels
it is posable you may have a seeping head gasket if it were overheating it would be a lot that is seeping on head gasket
on the intake it looks like someone put stop leak in it at one time

 

[RAU03MACH]

that brown lookin stuff looks like stop leak
i think your getting the plugs wet coolant on one or two plugs

 

[96blak54]

Cloud of white smoke and chugging?....thats not good. Dont drive the car anymore. Doing so will damage the piston rings and cylinder walls. It doesnt take long either.

Rau03mach said it best, seeping headgasket gasket. Could be a failed head bolt. Head could have developed a crack. The intake manifolds water channel could be weeping in one of the ports.

If it were me, id park the car and plan on at least a headgasket swap maybe with a machine shop head checkout.

 

[cobrajeff96]

If coolant is getting into the combustion chamber, you should be able to feel pressure on the palm of your hand when holding it just atop an open radiator or coolant reservoir, and the car does not need to warm up for this test either. You can cold start the car and check immediately for pulses. Another clue is if the tailpipes are continually wet even after the long drive. Tailpipes should normally be slightly black, sooty, and dry after engine fully warmed. And of course a loss of coolant is another symptom. If the spark plugs are excessively shiny due to essentially steam cleaning, there's a pretty good clue that coolant is being combusted.

 

[Chester5000]

If coolant is getting into the combustion chamber, you should be able to feel pressure on the palm of your hand when holding it just atop an open radiator or coolant reservoir, and the car does not need to warm up for this test either. You can cold start the car and check immediately for pulses. Another clue is if the tailpipes are continually wet even after the long drive. Tailpipes should normally be slightly black, sooty, and dry after engine fully warmed. And of course a loss of coolant is another symptom. If the spark plugs are excessively shiny due to essentially steam cleaning, there's a pretty good clue that coolant is being combusted.

While I didn't spend much time on the radiator cap or testing for pressure coming out of the reservoir loopback hose (whatever that's called), I drained all my coolant while removing the intake manifold and was surprised to see it's crystal clear and not muddy.

I do remember pulling that hose and waiting for bubbles and whatnot, but it's possible that the engine wasn't hot enough to get it moving maybe? I've really only idled it in my garage a few times since it happened, so it hasn't really been TESTED tested. I'm too afraid of killing the cats and other things like you mentioned.

Even on the old spark plugs, there was very little difference. Them being old and fairy sooty, I expected to see a visible difference from the "steam clean" effect.

Thanks for your help.

 

[Chester5000]

i would try a compression test on that side first one by one
do the other side after and compare
make sure the intake dose not have deep pits or gouges around water jackets and channels
it is posable you may have a seeping head gasket if it were overheating it would be a lot that is seeping on head gasket
on the intake it looks like someone put stop leak in it at one time

Dumb question - does the intake manifold need to be in place for a compression test?

Is there a test I should run on the lower manifold itself to look for liquid leaks?

I don't think it's overheating related as this only occured after a 1 mile drive to a gas station from home lol. The white cloud starts very quickly after initial acceleration.

RE: your stop leak comment - is that the rusty substance in the back you think? Another mechanic said it's very concerning for whatever reason.

 

[Chester5000]

Cloud of white smoke and chugging?....thats not good. Dont drive the car anymore. Doing so will damage the piston rings and cylinder walls. It doesnt take long either.

Rau03mach said it best, seeping headgasket gasket. Could be a failed head bolt. Head could have developed a crack. The intake manifolds water channel could be weeping in one of the ports.

If it were me, id park the car and plan on at least a headgasket swap maybe with a machine shop head checkout.

I assume just pulling it apart and looking for oddities around the heads would answer the bolt or crack question?

I really thought I would find a smoking gun with the lower manifold gasket but it looks totally fine to my non-mechanic eyes.

 

[RAU03MACH]

INTAKE dose not need to be in place
your doing the cylinders and heads with gasket

 

[RAU03MACH]

another way to test is a radiator pressurizer
test kit
you're filling the coolant jackets and all the jug/ head ports with air forcing coolant to enter those ports
it would force coolant in the head gasket if it were weak gasket
the coolant would really be coming out the tail pipes then

and to do that test you would need the intake on it