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Username Post: heat riser        (Topic#347640)
old apache61 
Forum Newbie
Posts: 30

Reg: 08-07-15
10-12-17 01:18 PM - Post#2710659    

I started up my 57 this morning. I only let it run for about 3 minutes. I had the hood up so I was looking to see if there were any leaks. None, but I noticed smoke coming from the heat riser connected to the manifold. 1. Should this happen? 2. Is it dangerous to run it like that? Thanks Gene



 

WagonMan 
"7th Year" Silver Supporting Member
Posts: 1609
WagonMan
Age: 69
Loc: Las Vegas, NV
Reg: 10-26-04
10-12-17 02:04 PM - Post#2710665    
    In response to old apache61

Has it been sprayed with any penetrating oil lately? If so, the oil was just burning off.

Charles

57 210 4dr. Wagon(bought '82)
-350/700r4 Mild Custom
56 BA 4dr. ht.(bought '98)
-265/TH350 Mostly Stock
29 Ford Sedan(bought '75)
-4.3L/TH350(in progress)


 
old apache61 
Forum Newbie
Posts: 30

Reg: 08-07-15
10-12-17 04:42 PM - Post#2710680    
    In response to old apache61

It doesn't have any oil on it. I was changing all the hoses last week. I started to car to check for any leaks and noticed the smoke coming from the heat riser. Is this safe to drive?



 
YOUNG57 
Contributor
Posts: 966

Loc: Tennessee
Reg: 12-06-10
10-12-17 07:57 PM - Post#2710697    
    In response to old apache61

Not enough information.

Are you talking about the passenger side exhaust manifold heat riser valve or the intake manifold heat riser exhaust cross over passage? What is the smoke, exhaust gases, paint, oil, heat hose water (steam)? What else have you changed?




 
old apache61 
Forum Newbie
Posts: 30

Reg: 08-07-15
10-13-17 04:47 AM - Post#2710710    
    In response to YOUNG57

The heat riser on the passenger side emits smoke as soon as motor heats up. There is no oil, paint etc. on or around it. I never done any work on the riser or exhaust system. I changed heater hoses. No leaks.



 
YOUNG57 
Contributor
Posts: 966

Loc: Tennessee
Reg: 12-06-10
10-13-17 07:07 AM - Post#2710720    
    In response to old apache61

“The heat riser on the passenger side emits smoke as soon as motor heats up.”

Sounds more like oil or something else dripping on it and burning off when hot. An exhaust gas leak should be immediate as soon as started and typically makes noise but is not visible smoke.

Do you hear an exhaust leak, popping or puffing noise? If it is an exhaust leak it can be dangerous. A leak in front of the passenger cabin, especially next to the heater duct, can draw in carbon monoxide and be deadly.

If it is an exhaust leak it could be either of two gaskets on the exhaust heat riser valve, a flat 3-hole one between it and manifold and a donut between it and the down pipe. The three bolts are typically very rusted and their nuts frozen, very difficult to remove, they typically break. Lots of penetrating oil, time and patience required to remove them.

The flat 3-hole gasket has a metal band around the center 2” opening to resist heat. Replace the donut gasket with a cast iron one that will last forever. If you can get the three studs out of the manifold (penetrating oil, time and patience required) replace them with stainless steel ones and brass nuts.

Good luck with your search for source of the smoke.




 
old apache61 
Forum Newbie
Posts: 30

Reg: 08-07-15
10-13-17 10:53 AM - Post#2710741    
    In response to YOUNG57

Maybe this is not a related problem. When I start up and rev it up I hear a like fog horn sound as though it isn't getting air??



 
YOUNG57 
Contributor
Posts: 966

Loc: Tennessee
Reg: 12-06-10
10-14-17 06:29 AM - Post#2710816    
    In response to old apache61

Does you exhaust manifold have the choke heat tube going thru it from top near center to bottom back? Is it still intact, not rusted thru or away? They often do corrode away over time and will leak exhaust gas out either or both ends.



 

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