Back of Cylinder Head LEAK
Thread Starter
Teching In
Joined: Aug 2017
Posts: 19
Likes: 0
Back of Cylinder Head LEAK Hi
So I just finished up head gaskets. I just purchased new steam pipe bolts and seals. But I’m still leaking from the lower inside bolt holes. Not sure if it’s supposed to be plugged? I had the heads surfaced and cleaned. Did I or somebody else miss something? It’s the one circled
So I just finished up head gaskets. I just purchased new steam pipe bolts and seals. But I’m still leaking from the lower inside bolt holes. Not sure if it’s supposed to be plugged? I had the heads surfaced and cleaned. Did I or somebody else miss something? It’s the one circled
You sure you have good seals on both sides of the crossover fitting? Banjo bolts are snug and not cross threaded?
Should be a seal between head and crossover, then a seal between the crossover and banjo bolt.
Should be a seal between head and crossover, then a seal between the crossover and banjo bolt.
Thread Starter
Teching In
Joined: Aug 2017
Posts: 19
Likes: 0
Correct I have 4 seals. I had issues tightening the old bolts so I purchached new ones that came with the seals for $18 all together compared to the $32 for the 4 seals from gm. I was nervous of screwing up the threads that I didn’t want to wrench on it to hard. As far as I can tell the fluid is leaking from that lower hole. I believe it is threaded. I can’t find any good images online of all the passages in the head
The holes that are not the steam vent, are not into coolant. So they cannot leak.
Try snugging the steam line banjo bolts up a tad. I would try and find a torque value but if the motor is in, good luck getting a torque wrench back there.
Did you clean the threads out on the heads prior to install?
Try snugging the steam line banjo bolts up a tad. I would try and find a torque value but if the motor is in, good luck getting a torque wrench back there.
Did you clean the threads out on the heads prior to install?
Trending Topics
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
Gas Monkey Built a 6-Wheel Ferrari Testarossa With a Corvette LT4 Engine
Verdad Gallardo
7 Most Reliable High-Performance Engines GM Has Ever Built
Verdad Gallardo
Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin
Verdad Gallardo
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo Thread Starter
Teching In
Joined: Aug 2017
Posts: 19
Likes: 0
I did not run a tap through but I assumed the machine shop did. I guess it doesn’t pay to assume. In total I have 8 seals because I bought them twice. I assume this is a no no but could you consider doubling up on seals if it’s close? I suppose it could be from the banjo bolts. But I feel I’ve put quit a bit of force behind it?
Reason I asked is I tested the tensil strength of that reverse cooling tube when I took the engine out of the car. When I bought a new one it came with banjo bolts and seals, but the seals were a small diameter with a thin seal. Got some A/C ones that were the same size as the GM part number. If you haven't already, examine the seal and see if it's ripped. Or just replace them with the extras and see what happens. Don't double up the seals.
TECH Veteran
Joined: Apr 2008
Posts: 4,985
Likes: 112
and isn't the threaded bolt and head "tapered".....and if so if the threads were chased on the head....would that have killed the taper??
Been awhile since I put my motor in and can't remember if the steam pipe bolts are tapered or not
I don't recall my banjo bolts being tapered, either.
What you can also do is get a coolant pressure tester, put the 18lbs or whatever it is the cooling system is rated for on a cold engine and see what happens.
What you can also do is get a coolant pressure tester, put the 18lbs or whatever it is the cooling system is rated for on a cold engine and see what happens.
Thread Starter
Teching In
Joined: Aug 2017
Posts: 19
Likes: 0
I suppose I haven’t been clear. The driver head is leaking when I add coolant. I’ve yet to start it since head gaskets. Can only imagine what other issues I may have. I can not get the bolt snug but it won’t turn anymore. From what I can tell it is aligned properly and not in sideways
I suppose I haven’t been clear. The driver head is leaking when I add coolant. I’ve yet to start it since head gaskets. Can only imagine what other issues I may have. I can not get the bolt snug but it won’t turn anymore. From what I can tell it is aligned properly and not in sideways
TECH Addict
Joined: Oct 2016
Posts: 2,513
Likes: 480
From: PDX-OR-USA
Hoping for the best,, the blind hole on the end of the head doesn't that back up to the water jacket? I have had a mounting bolt hole bottomed out by a shop replacing a bolt and it broke through, wasn't fatal, I just had to start using RTV on the bolt so it couldn't leak..
TECH Veteran
Joined: Apr 2008
Posts: 4,985
Likes: 112
have these heads been on your motor and in use before?
Thread Starter
Teching In
Joined: Aug 2017
Posts: 19
Likes: 0
I’ve unbolted and started over several times with both sets of seals. They were the original heads to the motor. I do question if the threads have been altered. I’m not sure how to check and see if the steam pipe itself is bad