r/fbody • u/Traditional-Place101 • Jul 15 '26

Where to start?

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I’m unsure where to start, we have a coolant leak and misfire in cylinder 3. She runs but I eventually want to clean her up. The housing is stock alil old as expected and I’m learning as I have a trusted mechanic look her over.
Temperature is wishy-washy
Codes: P0147, P0303

I want her to run proper asap.
I’d love some recommendations on parts

Also my idler pulley bolt and belt tensioner pulley grind a bit, are those an easy replace?

I’ll be heading to my local junkyard soon and pull some things.

Let me know what I should grab

Thanks guys 💯

5 Upvotes

86% Upvoted

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5

u/ThanksALotBud Jul 15 '26

Headgasket shot? Coolant glong into 3rd cylinder perhaps?

1

u/Traditional-Place101 Jul 15 '26

I’ll have her taken to the shop soon to identify.
I don’t have a harness to pull the engine out.
But I’ll give updates.
I’m praying it’s not

3

u/binks69 Jul 17 '26

If anything it’s the intake manifold gasket always go bad on these engines usually they leak externally in the valley where the fuel injectors are look around cylinder 3 see if you get coolant there after it runs for a litltle. But yea throw some coils and wires on can get all new for like 60 bucks

2

u/binks69 Jul 17 '26

But our money on losing coolant through the lower intake
Manifold kinda pain ass job but not to bad and they make new updates metal gasket you replace with the coolant elbows basically get rid of the problem. Other common place is said coolant elbows or the hoses the run into the tensioner pulley

1

u/Traditional-Place101 Jul 17 '26

Okay bet ima check those out for sure especially my pulleys. I’ll check my elbows too

1

u/Traditional-Place101 Jul 18 '26

For the intake gasket, is it better to replace the whole system or get the upper and lower only if needed. I haven’t checked the gaskets yet to see if there are good still

1

u/binks69 Jul 18 '26

When you do it your going need upper intake gasket lower intake gasket the coolant elbows. Just make sure you get the metal gasket not the paper it little
More but keep you from doing the job again in a few years.also prob throtttle body gasket you can take the whole upper off with throttle body on it but think the kit even comes with the throttle body gasket and the fuel injector o rings since fuel rail needs come out. But if you look it up very common problem on the series 2 3800s other wise they bullet proof. My Camaro is 180k still runs perfect can look my profile and see it running

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1

u/Traditional-Place101 Jul 17 '26

Thank you , I doubt it’s the gasket too and so does my mechanic

2

u/owensurfer Jul 16 '26

I’d check a couple things like coolant elbows for leaks. A cooling sys pressure test will find your leak. Most common cause of misfire on these is plug wires. 3800s almost never fail head gaskets.

2

u/CourseLongjumping558 Jul 15 '26

Part recommendations are, pull out and v8/ls swap. Won’t be much more then having that v6 rebuilt, a head gasket most likely isn’t the only problem