2000 OHV Exhaust Manifolds

[239]

Recently I noticed that my exhaust manifolds are rusted pretty bad. It definitely looks like there could be a pinhole leak on them, so I’d like to replace them. I’ve searched this site but can’t find anything on replacing the manifolds on a 2000 OHV. I just see people that upgraded to headers. From my research, it looks like Dorman makes both sides:
Manifold Right- Dorman 674378

Manifold Left- Dorman 674379

How hard is it to remove the bolts? I’m hoping they don’t break or round.

 

[Runnin'OnEmpty]

There are 6 studbolts holding the manifold on, and 2 attaching it to the crossover pipe. Start on the pipe bolts first to give support. They are bears to break loose, so use a 6 point socket along with extension and breaker bar. Soak in Kroil penetrant or something similiar for a few days first. Try loosening them with the engine warm.

Cast iron manifolds rarely rust through, so make sure you really need new ones before taking them off.

 

[239]

There are 6 studbolts holding the manifold on, and 2 attaching it to the crossover pipe. Start on the pipe bolts first to give support. They are bears to break loose, so use a 6 point socket along with extension and breaker bar. Soak in Kroil penetrant or something similiar for a few days first. Try loosening them with the engine warm.

Cast iron manifolds rarely rust through, so make sure you really need new ones before taking them off.

Thanks for the advice. I found it odd that they are rusted too, since the rest of the engine is fine. They’re corroded pretty bad on the top. Like the type of corrosion you’d see on a tailpipe. I’ll try to get a picture.

 

[Mbrooks420]

I agree with above. Make sure they are leaking, or you could be opening a real can of worms.

They may look rusty like a tailpipe, but if they are cast they are probably over 15 times as thick.

 

[239]

I agree with above. Make sure they are leaking, or you could be opening a real can of worms.

They may look rusty like a tailpipe, but if they are cast they are probably over 15 times as thick.

I’m going to test the exhaust with a shop vac first. I can hear exhaust leaking when I accelerate next to a wall. For example, while driving up a bridge. So maybe it’s just the gaskets. I recently replaced the egr and the tube was fine.

 

[Runnin'OnEmpty]

I've been fooled more than once by exhaust leaks. As you mentioned, the EGR tube is prone to rust through, and it's also a bear to remove from the exhaust pipe. I don't believe Ford used manifold and downpipe gaskets from the factory, but you can buy them aftermarket now. The manifold bolts are studbolts, so they might have loosened and allowed leaks. Sometimes you can see a white residue left at the site of an exhaust leak.

A mechanic's stethascope can locate an exhaust leak, and a length of old water hose makes a good substitute..

 

[239]

Here’s a picture of the passenger side manifold. There’s a spot that’s rusted pretty bad but if the manifolds are really thick, then I don’t think they would be leaking from there. The drivers side isn’t as bad, from what I can see.

 

[974X4BLACKSPORT]

That is normal surface rust, no where near going to be a hole, it is probably at least 1/8" thick there.

 

[239]

That is normal surface rust, no where near going to be a hole, it is probably at least 1/8" thick there.

Interesting. I’ll definitely have to hook up a shop vac to the tail pipe and test for any leaks before I buy anything.

 

[jet843]

just had my passenger side replaced at a shop a week ago -- now suddenly i'm having idling and rough engine issues.

P0172 & P1131 codes ---- CHECK ENG light is on