redlightning
Active Member
Is this hot spot normal on this exhaust manifold? This just looks like a problem. Also looks like something is leaking. Surveyor sent this to me. I think all 4 manifolds have this same spot.
Exhaust Manifold 8.2
- Thread starter redlightning
- Start date
Mine do not have those hotspots. I have about 150 hrs on twin 8:2s and the paint is uniform with no browning like that
redlightning
Active Member
Thanks! These motors have around 275hrs.
mrsrobinson
Well-Known Member
Red flag, literally
redlightning
Active Member
Would red flag from your perspective indicate walk away or is this something that needs service. New manifolds and such. I am a bit confused about the whole exhaust manifold/riser situation i have seen mentioned. I dont know if this is a problem on all motors and all years or on some motors and some years.
Pirate Lady
Well-Known Member
Weird, when I replaced mine in spring they were worn out yet didn’t do that. keep us posted what you find.
KevinC
Well-Known Member
If I am not mistaken these risers and elbows have catalytic converters in them. I wonder if that might have something to do with that.
-Kevin
mnm99
Well-Known Member
I couldn't imagine what those cost to replace. My friend has 2010 305 small blocks with catalytic converters and it cost him 8K to do 4 manifolds using the same cats....
mnm99
Well-Known Member
I couldn't imagine what those cost to replace. My friend has 2010 305 small blocks with catalytic converters and it cost him 10K to do 4 manifolds using the same cats....
Edit.. Manifolds around $600 each and if cats are needed add $1300 each for those.
Edit.. Manifolds around $600 each and if cats are needed add $1300 each for those.
paulswagelock
Well-Known Member
I am almost 100% certain your picture is from a Merc 8.1 and not an 8.2. You have some verifying to do
corrected by Mnm99, I stand corrected.
corrected by Mnm99, I stand corrected.
Last edited:
mnm99
Well-Known Member
joe searay
New Member
- Aug 18, 2017
- 1
- Boat Info
- 310 Sundancer 2007
- Engines
- 5.7 350 Mercruiser Horizons V drives
I have 2017 8.2 with single cats in my 2011 370Sundancer - I just got a quote for replacement $12,800 for 4 manifolds a risers and parts -its time 6 years old flushed each time used only 199hrs on both- Searay replaced motors in 2016 due to constant sensor faults- older 8.2 had 3 cats on each side of the manifold 6 per motor --- that picture looks like the older cat design 3 per manifold - this design was a problem - my new single cats run fine ( its critical to have good battries with these motors)or you will get sensors faults
mnm99
Well-Known Member
I have 8.1 and built a flush system. I went 7 years and just replaced them this fall. I cut them open and this is what they looked like. Now these are 8.1's so your castings may be different, but I was impressed on how thick they still were. I can tell you this though, My friend has the same engines as me. We both just replaced our tranny coolers. Mine 2004 his 2003. Because I flush and he does not, his were gacked up and all green inside. Mine still looked like they came out of the box. Just to give an Idea how much flushing helps. To answer your question. I don't know. I know those cat manifolds are crazy. My friend just did 5.0 motors and shopped around. Found better prices. Shop your self and see prices and ask your mechanic how much to install maybe.
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