Dealer says Low Compression Cylinder 8

[ice445]

You're right. But I think it's safe to say that the relative compression test show there's something wrong there? They also switched around the plugs and the issue stayed at 8.

Definitely asking for a leak down test tomorrow. Do you know what the possible outcomes of that can be?

Yes, relative compression/power balance is a very accurate test, and coupled with the persistent misfire you definitely have a problem there. But a leak down test and a borescope camera are two non invasive (nothing needs disassembled) ways to find out if it's the bottom end or the heads. If the heads are okay they can be re-used to save money.

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[moses19]

Yes, relative compression/power balance is a very accurate test, and coupled with the persistent misfire you definitely have a problem there. But a leak down test and a borescope camera are two non invasive (nothing needs disassembled) ways to find out if it's the bottom end or the heads. If the heads are okay they can be re-used to save money.

Thanks man, I'll do that tomorrow and post updates when I get them!

 

[Smunczen]

Hmmm you think they would help with anything? Not sure it was because of their tune. Never had any problems and always used 93 octane.

I think it’s worth try.

 

[Cobra Jet]

He can also call The Ford 800# and ask a Regional CSR if they too would be able to help with the cost of repairs.

https://www.mustang6g.com/forums/threads/the-ford-800-info-for-those-needing-it.111571/

if it were me - I'd go directly for the long block. I know it's costly, but if you're going to keep the car long term, it's better getting the entire assembly, rather than putting a band-aid on it and hoping nothing else comes up later down the road.

How far out of the warranty are you?

Powertrain is 5 years or 60k miles. If you're not that far beyond, Ford may offer some assistance.

 

[DivineStrike]

Hey guys looking for some advice here. Yesterday car threw a Cylinder 8 Misfire and Misfire on Startup code. Took the car into the dealer and they said cylinder 8 has low compression(see pictures). I was hoping that at worst it would be the Intake Manifold issue thats pretty common, but it doesnt seem to be.

They gave me 2 options. Order a longblock and be done with it or do a teardown and see what potentially might be wrong. Car has the Ford Performance Power Pack 2 and exhaust, that is it. Only symptoms were a slight rumble at idle and a weird start up. Also, I am out of warranty so unfortunately im going to have to eat the cost. Any advice? Any specific questions I should ask them? What would you guys do? Thanks.

how much did this test run you out of curiosity?

 

[moses19]

He can also call The Ford 800# and ask a Regional CSR if they too would be able to help with the cost of repairs.

https://www.mustang6g.com/forums/threads/the-ford-800-info-for-those-needing-it.111571/

if it were me - I'd go directly for the long block. I know it's costly, but if you're going to keep the car long term, it's better getting the entire assembly, rather than putting a band-aid on it and hoping nothing else comes up later down the road.

How far out of the warranty are you?

Powertrain is 5 years or 60k miles. If you're not that far beyond, Ford may offer some assistance.

I'll try calling a Ford CSR rep. Yeah I decided to go long block because I would not have the peace of mind ever again if my engine were torn down.

It's a 2015 so by about a year. And I'm at 55k miles.

 

[moses19]

Sell that thing to a E-car company and buy a new one. That would be the most cost effective option if the car still runs and drives well.

Seriously considered this, but it's noticeable when you drive so I think they'd offer me less for it. That along with car prices right now would put me in a similar position financially if I were simply to try to sell and get into another Mustang.

 

[moses19]

how much did this test run you out of curiosity?

$165, an hours labor, but they waived it when they gave me the bad news lol

 

[DivineStrike]

$165, an hours labor, but they waived it when they gave me the bad news lol

Ah well uh I suppose that’s a win.... sorta

 

[IPOGT]

If really just depends on what they offer and the cost of a new engine. If it’s 5k(no) it’s a toss up. Anything over that and you could trade up pretty easy. At 10k dunk it and get a new one.

Its a tough spot either way though. Best of luck with it.

You could always get an FP crate coyote at a forum discount and have the dealer install it. Or, there’s always good engines from a failed car show vs. GT episode to be had.

 

[Robert3487]

I have a 17 with 45k and im also replacing the long block. I took it to another mechanic for a second opinion and leakdown test. They’re installing the new engine as we speak its about $9,600 for a new engine installed. I couldn’t find used engines for less than $8,500 and those had 60k miles on them.

 

[IPOGT]

I have a 17 with 45k and im also replacing the long block. I took it to another mechanic for a second opinion and leakdown test. They’re installing the new engine as we speak its about $9,600 for a new engine installed. I couldn’t find used engines for less than $8,500 and those had 60k miles on them.

What caused your block to fail?

 

[Robert3487]

What caused your block to fail?

Low oil and high RPMs lol, I had my car die after a race when I put the clutch in. It still started up and got me home but it immediately threw a code for over advanced camshaft position. The leak down test showed the bottom end was bad. So it is currently getting a new engine and Roush axle-back. The previous owner had some no name exhaust "aero turbine" mufflers. I thought it may have been the tune but it was low oil, my car was apparently burning it very quickly and I didn't catch it in time.

 

[IPOGT]

Sorry dude. That sucks. Bright side, you’ll be 100% going forward.
Is it better/cheaper to buy a Ford performance Aluminator Coyote from for instance CJ’s and have it shipped to the dealer or a service replacement engine?

 

[moses19]

I have a 17 with 45k and im also replacing the long block. I took it to another mechanic for a second opinion and leakdown test. They’re installing the new engine as we speak its about $9,600 for a new engine installed. I couldn’t find used engines for less than $8,500 and those had 60k miles on them.

That's crazy. I'm going for a new long block myself, not the entire engine.

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