1997 F250 4X4 5.4L. I had posted a problem before about the engine having a chirping noise on the passenger side when it was cold. Someone had suggested looking for this and when I got the opportunity to look, there it was. At least on of the bolts on the rear exhaust manifold port is broken. I know it will have to be fixed if for no other reason than that it is annoying. I was wondering though, will this cause any type of performance problems, such as running a little rich, or any thing along those lines, especially with a load behind it? This was brought up as a possibilty by the guys at the autoparts and I would like to get ya'lls thoughts. Thanks.

 

Are you absolutly positive this is where your noise is comming from ? I don't think that's it and even with the bolts busted , you have to still sealed or you would definitly know it and would have to fix pronto. I think your noise may be generating from a cold cat heat sheild that heats and expands quickly after start up . There is a simple fix for this with some 6-7" band clamps -

 

I will check this out. It's probably alot cheaper to fix if that is it. Would this cause it to run richer than normal or that nasty smell I get out of it when it heats up? This has definitely been a learning experience, and I would like to learn all I can about before I dump a grand on new cats and exhaust that I don't need. Not right now anyway.

 

OK.I crawled under it today and done some more looking. Both of the bolts on the back port are broken and there is some black **** on the block, or head on the bottom side. When you accelerate there seems to be a little hot air coming out there as well. This also seems to be where the sound is coming from. Jbrew, you mentioned that this needed to be fixed pronto. What problems can this cause me, and does any body have a ball park figure on cost?

 

Well , I can't beleive you don't have a MIL (engine light) illuminated - that don't make sense - you should be getting more than one code set. Maybe someone else can make sense of this..Idunno, sorry..

 

It takes a pretty large leak to set off the check engine light. My truck has both studs broken like his. This has never set the light off. Both outer y-pipe studs rusted out. The leak was loud on the left side. It never set the light. Fixed it then the right side broke. It was LOUD. It did finally set a lean code, but I had a loaded car trailer on the highway before it set a code. I've been driving my truck for about 3 years with broken rear manifold studs. Other than an annoying tick when cold, there have been no other issues.

 

Will you have a problem passing emission test with a leaky exhaust manifold?

 

It depends on the inspector. Some will not test the car if they hear a leak. I'd think if the light is not on that it will pass a sniffer or OBD II test without issue

 

thanks man

 

So far there is no cel. If this gets worse, to the point of a cel, what problems can or will it cause? As far as an inspection, we don't have them here in sunny South Alabama . Thanks.

 

Why don't you just fix it???

 

Proabaly will. I was just curious.

 

LOL , well okay, good deal!!

The problems that I can see is with O2 switching which should bring about lean codes and vibration which could cause many more problems as time goes on, O2's , that's just a minor one.

You have the 5.4L which is a CoilOnPlug (COP) motor, vibration with the heads could cause problems such as "Spark Plug Blowout" which is a known issue in these motors. Trust me , you don't want that problem - $$$$$$

That's what I meant by fixing it "pronto"..

I would check the plugs now to make sure there torqued between 12-20 ' lbs. My right manifold was replaced in 99 because the bolts broke off under warranty - then my motor blew in 2000 and it was replaced under warranty (dealership service error- no oil was put in my motor).

Mine have come loose before with #4 on my motor being only finger tight at one time. Also a guy in an Expedition called me from gas station with one of his plugs dangling- #3 It happens quite a bit , so I would check them if I were you, especially with the extra vibration..

Good Luck

 

Thanks.

 

This is an update to a problem that I had chased for little while. After getting the studs replaced, the chirpping noise has stopped. The truck seems to run pretty good cosidering. I do have a question about the O2 sensors though, as I have heard several stories. If the front sensors go out, does it indead cause the engine to default to running rich? What about a code? Will the front sensors throw a code or not? I have heard yes and no on this one. Anyway it does still have that rich smell to it, but no code. The truck has 156k on it, and far as I know they have never been changed. Thanks.