Bubbling at spark plug
Thread Starter
|
4wd Low
Joined: Apr 2025
Posts: 14
Likes: 0
Bubbling at spark plug
Hello,
slowly been cleaning up and fixing up an old 90 300, started her up today after replacing starter and was looking around the engine bay and found that cylinder 6 was bubbling out of the spark plug & the surrounding area is wet and caked with sludge.
I have included a video attached, any idea what the issue/fix is? Didn’t have time to play with it
slowly been cleaning up and fixing up an old 90 300, started her up today after replacing starter and was looking around the engine bay and found that cylinder 6 was bubbling out of the spark plug & the surrounding area is wet and caked with sludge.
I have included a video attached, any idea what the issue/fix is? Didn’t have time to play with it
Cargo Master
Joined: Jan 2004
Posts: 3,118
Likes: 149
From: South Dakota
Not a big deal. Just clean out around the spark plug with whatever method you use. Then you can try to tighten the spark plug or loosen it slightly and try tightening it. Or buy a new spark plug or a set and put it or them in after cleaning around the plugs. Note you probably won't notice the leak if still there until some oil or other liquid builds up around the plug again.
Cargo Master
Joined: Jan 2004
Posts: 3,118
Likes: 149
From: South Dakota
[QUOTE=Jack Morgan;21557148]Missed as in, it’s actually a cracked cylinder head? 😭[/QUOTE
YES. When Conanski had a different answer(his post appeared while I was typing, I am a slow typer and even slower thinker) I knew I had to take another look. The liguid is coming through the spark plug from inside the cylinder. I assume you are losing coolant? Or you will soon notice that you are losing coolant. It could be a leaking head gasket though.
YES. When Conanski had a different answer(his post appeared while I was typing, I am a slow typer and even slower thinker) I knew I had to take another look. The liguid is coming through the spark plug from inside the cylinder. I assume you are losing coolant? Or you will soon notice that you are losing coolant. It could be a leaking head gasket though.
Thread Starter
|
4wd Low
Joined: Apr 2025
Posts: 14
Likes: 0
[QUOTE=88n94;21557165]
haven’t been able to drive it much since I had to replace some other first so not sure if it’s losing coolant yet.
No exhaust smoke though, oil also looks good.
Truck does take some effort to get started though, gotta keep giving it gas or it’ll idle and die until it warms up. Kind of erratic RPM fluctuations & a real strong gas smell.
RPMs don’t seem to match the effort I’m giving the pedal though, light tap it might rev high, pushing down sometimes will kill the power/RPMs then be fine if I let up on it a little
Missed as in, it’s actually a cracked cylinder head? 😭[/QUOTE
YES. When Conanski had a different answer(his post appeared while I was typing, I am a slow typer and even slower thinker) I knew I had to take another look. The liguid is coming through the spark plug from inside the cylinder. I assume you are losing coolant? Or you will soon notice that you are losing coolant. It could be a leaking head gasket though.
YES. When Conanski had a different answer(his post appeared while I was typing, I am a slow typer and even slower thinker) I knew I had to take another look. The liguid is coming through the spark plug from inside the cylinder. I assume you are losing coolant? Or you will soon notice that you are losing coolant. It could be a leaking head gasket though.
No exhaust smoke though, oil also looks good.
Truck does take some effort to get started though, gotta keep giving it gas or it’ll idle and die until it warms up. Kind of erratic RPM fluctuations & a real strong gas smell.
RPMs don’t seem to match the effort I’m giving the pedal though, light tap it might rev high, pushing down sometimes will kill the power/RPMs then be fine if I let up on it a little
Trending Topics
Cargo Master
Joined: Jan 2004
Posts: 3,118
Likes: 149
From: South Dakota
You can probably tell that coolant is getting in that cylinder by removing that spark plug. You may have to use it a little longer to make it clearer to tell.
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
Top 10 Fords at 2026 Carlisle Ford Nationals
Joe Kucinski
3 Best / 3 Worst Parts of Modern Ford Ownership
Brett Foote
10 Amazing Upgrades That Solve Common Ford Truck Owner Headaches
Pouria Savadkouei
Every 2026 Ford Engine Explained
Brett Foote
10 Ugly Ford Trucks That We Still Kinda Love
Joe Kucinski
10 Things Every Truck Owner NEEDS (2026 Edition)
Michael S. Palmer
Rezvani's Latest Post-Apocalyptic Monster Is a Ford F-150 Raptor Underneath
Verdad Gallardo
Top 10 Most Expensive Ford Trucks Ever Sold on Bring a Trailer
Joe Kucinski
2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)
Brett Foote
Thread
Thread Starter
Forum
Replies
Last Post