1994.5 - 1997 7.3L Power Stroke Diesel  

Possible blown HG, need help to diagnose.

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  #16  
Old 07-16-2014, 04:15 PM
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I've read a few articles about head gasket quality and most say to stick with the ford ones. Felpro and a few others that I can't think of don't seem to have the quality.
 
  #17  
Old 07-16-2014, 04:31 PM
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Originally Posted by Chris56ford
The injector cups seal in two spots with green locktite, one on each side of the water jacket in the head. A crack in the cup in the area of the water jacket will put diesel in the coolant. But if the lower seal is not sealed right it will leak coolant and allow combustion gasses into the coolant system. There will be no raw diesel in the coolant system in this instance. He said all 8 cups were replaced, so a crack is unlikely but one might not be sealed well.
Thanks. I'll put that into my brain vault!

Might as well get the head fluxed if you end up pulling it out.

Keep us posted if you figure anything out.
 
  #18  
Old 07-16-2014, 05:14 PM
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Originally Posted by Chris56ford
They are probably fine, I was just explaining to williamub that there doesn't have to be diesel in the coolant with a cup leaking.

I think your only option at this point for the leak is to pull the head and see if its the head gasket, it most likely is. That sucks man!
Thanks for the help all. I will probably pull the head. Before I do, I really want to find the cause of the knock. If its in the bottom end, there's no sense in doing head gaskets just to have something else fail in the near future. I'm replacing a cracked tank on my other truck right now, but once that's done i'll poke around the powerstroke with a stethoscope and see what I can't find.
 
  #19  
Old 07-16-2014, 05:45 PM
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Just went and let the truck warm up and took it for a spin. I can honestly only hear the knock at idle and when i partially touch the throttle, then it just blends in with the rest of the noise. I can't generalize it to one area. With the stethoscope put to the exhause manifold, it was making all sorts of sounds, but it did it on both sides of the motor. It sounds like it's just the motor in general. I can't decide if its just a noise these motors make, or its abnormal.
 
  #20  
Old 07-16-2014, 06:21 PM
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Is it like a steady tick,tick,tick? My truck's vacuum pump does that when it's a cold start at idle. As soon as it warms up, that noise seems to fade away (yes, I know I probably need to replace the vacuum pump). Could also be you have a small exhaust leak maybe? I've head those on the big truck diesels that I could swear was rod knock.
 
  #21  
Old 07-16-2014, 06:31 PM
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Originally Posted by dizzyfingers03
Is it like a steady tick,tick,tick? My truck's vacuum pump does that when it's a cold start at idle. As soon as it warms up, that noise seems to fade away (yes, I know I probably need to replace the vacuum pump). Could also be you have a small exhaust leak maybe? I've head those on the big truck diesels that I could swear was rod knock.
the noise didn't fade at all throughout cold to warm. It doesn't quite sound like an exhaust leak, as my 95 460 has a really good one and it's a totally different sound. But I'm not too familiar with diesel exhaust leaks.
 
  #22  
Old 07-16-2014, 07:33 PM
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New update. I went through and unplugged each injector one at a time to see if the noise would disappear, to eliminate injector knock. Well the noise was still alive and well. Realized the best place i could hear the knock was laying under the motor.
 
  #23  
Old 07-16-2014, 09:26 PM
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Oh man, laying under the motor is loud! LOL
 
  #24  
Old 07-16-2014, 10:55 PM
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Its when one of these is quiet that you should worry!
 
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