new head gaskets, now runs rough and smokes

gmduramax

Shits broke
Jun 12, 2008
4,072
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Nor cal
So, I did some google researching and found that I may have a boost issue. Popped the hood and started checking all my clamps that had to do with air, low and behold the hard plastic fitting on the hot side (pasngr side) below the airbox was not fit properly so I refit the coupling with the funky ring that holds it together, I'm now in business again, runs like it did before, perfect, But I still have the coolant coming from the bellhousing at the bottom, a constant drip. I guess there are 2 plugs on the back side of the block that could be leaking, that sux, I'd have to drop the tranny to get to them unless there may be something else just can't see behind there from up above and with a camera probe can't see well enough.... arg...
It’s not the cover on the rear adapter that’s leaking?
 

TheBac

Why do I keep doing this?
Staff member
Apr 19, 2008
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Theres a small rectangular cover on the passenger side of the adapter plate, above the starter area, just behind the uppipe and downpipe. The gaskets on those are a known issue.
 

IdahoMike

Member
Jul 12, 2020
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Theres a small rectangular cover on the passenger side of the adapter plate, above the starter area, just behind the uppipe and downpipe. The gaskets on those are a known issue.
HMMmmm, I'll have to check it out tomorrow... whats it for??
 

TheBac

Why do I keep doing this?
Staff member
Apr 19, 2008
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Mid Michigan
Thats one of those questions about the Dmax that was never answered. Who knows......
 

IdahoMike

Member
Jul 12, 2020
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Thats one of those questions about the Dmax that was never answered. Who knows......
appears that is the culprit, what PITA to get to like everything else on these, but what a joy.... NOT.... Thanks gmduramax and The Bac, you guys have been a big help... Lets see what else comes up during this endeavor...:rolleyes:
 

IdahoMike

Member
Jul 12, 2020
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well of course it wasn't the adapter plate, still leaking, coming out the psngr side of the weep hole at the bottom of the bell housing. I did look on other forums. Other folks had/have this same problem but never said what it was, they just quit posting, how rude... So if anyone out there found the leak at the back of the engine let me know. I will continue the search...
 

IdahoMike

Member
Jul 12, 2020
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Update: I was able to locate the infamous coolant leak. After crawling under the hood then peering on the drivers side around the turbo with a LED adjustable flashlight I was able to bend my right eyeball around the hoses, wire looms and other crap, I noticed some coolant on the top of a bolt head. I starred at it for a few seconds then out the corner of my left eye I spotted a drip. I had to hold steady and not breathe then there it was again, then again about every 5 seconds. Damn thing is under the turbo. This ought to be fun. I get the privilege of taking all the top stuff back off again, I'm getting real good at it. I think while I'm in there I'm going to reroute what ever cooling and fuel lines I can that go under the EGR, coolant hoses, thermostat housing and put them up where I can get to them... Has anyone done this???
 

IdahoMike

Member
Jul 12, 2020
52
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Well, at least you found the culprit.
yes, finally.... so I figure I'll replace the water pump while I'm at, it has a slight leak now. any suggestions on which one to use, should I get just the pump or spend an extra benjamin and get the full monty (pump and housing). I'm leaning towards just the pump as my housing is fine, unless there's something I don't know that may deem it unworthy...
 

DAVe3283

Heavy & Slow
Sep 3, 2009
3,724
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Boise, ID, USA
Get a factory water pump, some of the cheap aftermarket units have caused problems with gear mesh.
When you pull your pump off, look for pitting inside the housing. If there is minimal pitting, just replace the pump. I've even reused the housing with pretty severe pitting before.

Sent from my FlashScan V2 using Tapatalk
 
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LBZ

Super Moderator
Staff member
Jul 2, 2007
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I was gonna say to check the turbo coolant lines. As these trucks age problems like this are becoming more and more prevalent.
 

IdahoMike

Member
Jul 12, 2020
52
5
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I found out there was a banjo fitting leaking beside the turbo I tightened it and stopped that one. While I was checking it I seen a drip by the heater inlet pipes and sure enough that was dripping as well, the cheap plastic adapter had a small crack and was dripping. It was in a spot that was tough to see. I'm going to see if I can get rid of that and just slide the heater hose over the inlet pipe and clamp it. I rented a system pressurizer, hooked it up and found these leaks which made it really drip and easy to find. I would recommend if you have any sort of drip get the pressurizer and charge the system with coolant in it. My water pump is leaking out the weep hole, so I'll be replacing that this week. When it rains it pours...
 

Chevy1925

don't know sh!t about IFS
Staff member
Oct 21, 2009
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Phoenix Az
I found out there was a banjo fitting leaking beside the turbo I tightened it and stopped that one. While I was checking it I seen a drip by the heater inlet pipes and sure enough that was dripping as well, the cheap plastic adapter had a small crack and was dripping. It was in a spot that was tough to see. I'm going to see if I can get rid of that and just slide the heater hose over the inlet pipe and clamp it. I rented a system pressurizer, hooked it up and found these leaks which made it really drip and easy to find. I would recommend if you have any sort of drip get the pressurizer and charge the system with coolant in it. My water pump is leaking out the weep hole, so I'll be replacing that this week. When it rains it pours...
napa has steel adapters if you want to go that route. the hose wont fit over the barb end without ALOT of persuasion and the ridge is so big, it leads to the hose cracking. if you put it on and just crank it down with a clamp before the ridge, it will work but runs the possibility that if pressure gets too high, it will blow off. I have done the latter without issue before but dont really recommend it. the steel adapters are good insurance.
 

IdahoMike

Member
Jul 12, 2020
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Thanks Chevy1925, I picked up a metal one this morning at O'Reilly's. Now I have to get the old one off, any tricks?? I have the removal tool. this thing will not budge, not much room to work on it and don't want to break the metal inlet...
 

Chevy1925

don't know sh!t about IFS
Staff member
Oct 21, 2009
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Phoenix Az
Thanks Chevy1925, I picked up a metal one this morning at O'Reilly's. Now I have to get the old one off, any tricks?? I have the removal tool. this thing will not budge, not much room to work on it and don't want to break the metal inlet...

work the plastic part in circles (try to spin it), once thats free, usually you push it in a bit, slide the removal tool down as far as you can while pushing in, and then slide everything back in a twisting motion. the tool will stop when it hits the ridge but the plastic nipple will keep coming off.

they are usually brittle enough you can break them with pliers too. Just dont go leveraging it up and down, try to smash it without collasping the steel tube under it. you just gotta get the outer casing area broke off to get the clips to undo, then it slides off.
 

IdahoMike

Member
Jul 12, 2020
52
5
8
work the plastic part in circles (try to spin it), once thats free, usually you push it in a bit, slide the removal tool down as far as you can while pushing in, and then slide everything back in a twisting motion. the tool will stop when it hits the ridge but the plastic nipple will keep coming off.

they are usually brittle enough you can break them with pliers too. Just dont go leveraging it up and down, try to smash it without collasping the steel tube under it. you just gotta get the outer casing area broke off to get the clips to undo, then it slides off.
Update: everything is running mint, and no leaks... I replaced the heater hose connector with a metal one, replaced the water pump, tightened up all the air piping and now my Mad Max is up and running again... Thanks all for the help in figuring this one out... I learned a ton about my truck from you guy's and am not all hesitant to work on anything...
 
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