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Discussion Starter · #1 ·
Hey guys,
I just discovered a small coolant leak between my lower intake gasket and the head. It is located right at the front of my 2000 7.4 intake on the passenger side. While browsing in a recreational vehicle forum, I saw a thread that stated this was a common problem for the 7.4. I was just wondering if there was a recall for this or where I might look to find recalls on chevy trucks. I have searched this forum but to no avail.

Thanks in advance
chevygolf
 

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Sorry, no recals. The vortec engines use low clamp bolts with improved gaskets, everything from 4.3, 5.0, 5.7 and 7.4 share this problem. Dexcool works very differenty then the old green coolant and tends to show small leaks sooner. The old 5.7l engine use to have a intake torque spec of 35ftlbs, now it's 9-11 ftlbs. If you have any maechanical ability it's not a hard job. Flush the cooling sytem first, reseal the intake and make sure you do a oil change right after. Find the correct torque spec, follow the sequence and you will do fine.
 

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Discussion Starter · #3 ·
Thanks Vortec, can the upper and lower intakes come off as one unit? Looks like my vacation is going to be a little shorter than I had anticipated.
 

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I havent' done a intake on a 7.4l in so long I honestly can't remember. The 5.7 come off together but thats because of the fuel rail spider, 7.4l is tataly different, there may be a couple of bolts either side hiding under the upper. Personal opinion.....depending on the mileage I would take them off seperatly. If you are going to reseal the lower intake, take the upper off, now you can check the injectors and rails for any leaks or problems, then when it goes back together with a new upper plennum gasket you know everything from the intake up is 100%. For ease of the job, the aluminum intake plus the aluminum plennum is alot of weight to line up when dealing with silicone on the block ends. Buy the gm gaskets and gm silicone, the silicone is expensive but it is the best product out there by far. Not sure of the torque specs off hand, cna check for you tomorrow if you havent found them by then.
 

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Don't use the GM gaskets because their part of the problem in the first place. Use fel-pro gaskets and Right-stuff silicone and you will never have this problem again. The fel-pro gaskets are made from a different material that won't deteriate like the GM oem gaskets.
 

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It's gonna be difficult getting the lower off with the upper still attatched. Try pulling the distributor and getting at the fuel rail that's mounted inbetween the two and not to mention all the bolts that hold the lower on are accessed through the intake runners...upper HAS to come off. And be sure to use GM gaskets...they are redesigned for this problem. I put Fel-Pro's on a 350(R) and they lasted 5 months. Stick with OEM. Aftermarket junk causes problems...Just my .02

Apply sealer to all the lower bolts. Tq to 22ft lbs, and second pass of 30ft lbs in sequence
Upper tq to 71in lbs, and second pass of 13ft lbs in sequence...
 

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You must of used the older design fel-pros because the newer ones are steel with the embedded rubber seal, not plastic crap like the oem design. My dad just replaced a set of these last week on a 350 and he had replaced before with gm gaskets and it was leaking antifreeze and also had a intake runner seal failure on # 5, causing a miss. Junk oem gaskets plastic material failed and sagged completley below the port.
 

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Discussion Starter · #8 ·
Thanx guys, I'll take off the intakes separately. I'll keep you posted as to the progress.

On the gaskets, most of them advertise "extra sealant" around the water jackets to fix the oem problem. All gasket manufacturers seem to be aware of the problem.
 

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FYI... I just finished the same job on my 5.7 Sub for the 2nd time, and used GM gaskets. The GM parts now come with a metal insert around the bolt holes that allows a little more torque to be applied without crushing the gasket. These seemed to work better than the first-version GM gaskets. I bought a set of Fel-Pro the first time I did the job but didn't use them, and they did not have the steel insert.

One final tip.... be SURE to use red LocTite on the manifold bolts. For this to work properly, you must also clean all of your manifold bolts and the mating threads in the heads thoroughly using a good degreasing solvent. Since the bolt torque is so low for these fasteners, they will loosen up in a very short time if not adequately "glued" in place.
 

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Blk04MD;1630484; said:
You must of used the older design fel-pros because the newer ones are steel with the embedded rubber seal, not plastic crap like the oem design. My dad just replaced a set of these last week on a 350 and he had replaced before with gm gaskets and it was leaking antifreeze and also had a intake runner seal failure on # 5, causing a miss. Junk oem gaskets plastic material failed and sagged completley below the port.
we always use fel-pro's redisegned metal/rubber gaskets...the platic oem ones are junk..plain and simple. why replace a poorly designed part...with a newer poorly designed part. its not the bolt holes that are the problem...its the plastic part that deteriorates with heat/cold cycles and eventually cracks.
 

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Discussion Starter · #11 ·
viabill;1648445; said:
FYI... I just finished the same job on my 5.7 Sub for the 2nd time, and used GM gaskets. The GM parts now come with a metal insert around the bolt holes that allows a little more torque to be applied without crushing the gasket. These seemed to work better than the first-version GM gaskets. I bought a set of Fel-Pro the first time I did the job but didn't use them, and they did not have the steel insert.

One final tip.... be SURE to use red LocTite on the manifold bolts. For this to work properly, you must also clean all of your manifold bolts and the mating threads in the heads thoroughly using a good degreasing solvent. Since the bolt torque is so low for these fasteners, they will loosen up in a very short time if not adequately "glued" in place.
Thanx for the tip. I have a glass beader at home so I'll clean all the bolts perfectly. Then I'll run a tap into the heads and make sure they are clean as well.
BTW how long did it take you? Were there any parts you had to run and get? You know anything unexpected?
 
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