LQ4 problem, broke-through head water jacket
01-03-2015, 03:14 PM
#1
Teching In
Thread Starter
Join Date: Jan 2015
Posts: 10
Likes: 0
Received 0 Likes
on
0 Posts
LQ4 problem, broke-through head water jacket Hello, I'm new, I live near Raleigh NC.
I'm a college student going for Mech Engr.
My only automobile engine work comes from a 1st gen S10 where I replaced the 2.8 60V6 with a crate 3.4 60V6 and had the intake bored out to take a 4.3 TB as well as modified the 4.3 TB to accept the 2.8 accessories. cleaned up the engine side of the truck and made a couple other small modifications.
On with my problem...
I have an H2 so from what I understand it is a LQ4 with aluminum 317 heads.
About 10k miles ago I had an exhaust manifold bolt break on the passenger side(no noise), I easily unscrewed the broke bolt using vise grips as it was still sticking out of the head, everything was good. Fast forward a month ago the driver side started making a ticking noise, all 6 bolt heads were still in place, without applying very much torsion 3 broke, 2 in the head, one still sticking out.
I didn't want to deal with the problem as I had exams going on and other obligations, so I sent it to a local mechanic. That turned out to be a very bad decision, the guy hit the water jacket twice, used an epoxy to try to seal the hole etc. It lasted about 1-2 weeks, I've tried high temp permatex to seal the leak(didn't work), but I'm not going to continue to bandaid this.
The head and exhaust manifold must be replaced, Maybe after college I will do performance engine work but as for now I'm more concerned about the truck performing reliably and well under all conditions.
In my mind it's not possible to replace just one head due to problems with differing compression on the two sides. However a very experienced engine builder has (hesitantly) said it would be ok to put a brand new(from GM) head in place of the messed up head.
On Monday I'm planning to go to a LS shop near me and get some ideas as I want this work started soon. My number 1 requirement is quality and reliability, I don't want anyone to know the engine was opened other than maybe half of the engine is cleaner. (Maybe some ARP studs depending on cost).
Can I replace just one head?
Do both heads still need to be pulled?
Should I buy a brand new manifold?
Should I buy a brand new head?
While quality of work is number 1 on importance, cost is a very close second.
Secondly, What is involved in this, While I feel I could do this, I simply don't want to mess with anything that requires measuring tolerances other than bolt/nut torque specs.
What is the best course of action? Try it myself or pay someone that has done this a multitude of times to do this.
Finally, what is a good rough estimate of cost, included with your suggestion.
Many Thanks!
I'm a college student going for Mech Engr.
My only automobile engine work comes from a 1st gen S10 where I replaced the 2.8 60V6 with a crate 3.4 60V6 and had the intake bored out to take a 4.3 TB as well as modified the 4.3 TB to accept the 2.8 accessories. cleaned up the engine side of the truck and made a couple other small modifications.
On with my problem...
I have an H2 so from what I understand it is a LQ4 with aluminum 317 heads.
About 10k miles ago I had an exhaust manifold bolt break on the passenger side(no noise), I easily unscrewed the broke bolt using vise grips as it was still sticking out of the head, everything was good. Fast forward a month ago the driver side started making a ticking noise, all 6 bolt heads were still in place, without applying very much torsion 3 broke, 2 in the head, one still sticking out.
I didn't want to deal with the problem as I had exams going on and other obligations, so I sent it to a local mechanic. That turned out to be a very bad decision, the guy hit the water jacket twice, used an epoxy to try to seal the hole etc. It lasted about 1-2 weeks, I've tried high temp permatex to seal the leak(didn't work), but I'm not going to continue to bandaid this.
The head and exhaust manifold must be replaced, Maybe after college I will do performance engine work but as for now I'm more concerned about the truck performing reliably and well under all conditions.
In my mind it's not possible to replace just one head due to problems with differing compression on the two sides. However a very experienced engine builder has (hesitantly) said it would be ok to put a brand new(from GM) head in place of the messed up head.
On Monday I'm planning to go to a LS shop near me and get some ideas as I want this work started soon. My number 1 requirement is quality and reliability, I don't want anyone to know the engine was opened other than maybe half of the engine is cleaner. (Maybe some ARP studs depending on cost).
Can I replace just one head?
Do both heads still need to be pulled?
Should I buy a brand new manifold?
Should I buy a brand new head?
While quality of work is number 1 on importance, cost is a very close second.
Secondly, What is involved in this, While I feel I could do this, I simply don't want to mess with anything that requires measuring tolerances other than bolt/nut torque specs.
What is the best course of action? Try it myself or pay someone that has done this a multitude of times to do this.
Finally, what is a good rough estimate of cost, included with your suggestion.
Many Thanks!
Last edited by iwillnc; 01-03-2015 at 03:17 PM. Reason: add information
01-07-2015, 05:50 AM
#3
Just replace the one head. No you do not have to pull both heads. Get new GM head and exhaust manifold bolts, one new head gasket. You can reuse the intake gaskets and the exhaust manifold gaskets. Use anti seize on the exhaust manifold bolts so they will not freeze up again.
You can find used 317 heads and used manifolds. It may be hard, depending on where you live. Post in the for sale/buy section---you may get lucky.
Don't know prices on these parts---used head should be 250 bucks, manifold 75 bucks. Labor 600 bucks, anti freeze 30 bucks??
Good luck
You can find used 317 heads and used manifolds. It may be hard, depending on where you live. Post in the for sale/buy section---you may get lucky.
Don't know prices on these parts---used head should be 250 bucks, manifold 75 bucks. Labor 600 bucks, anti freeze 30 bucks??
Good luck
01-07-2015, 01:52 PM
#4
Teching In
Join Date: Jan 2015
Posts: 2
Likes: 0
Received 0 Likes
on
0 Posts
Just replace the one head. Check Craigslist and Ebay for a used one. I wouldn't even worry about whether they're the same casting number at this point, as it seems the differences between the stock heads are pretty minor, and on an H2 the RPM ranges that you run in you wouldn't even notice them.
If you want to attempt replacing the parts yourself you're probably looking at 1 days work and about $100-$150 in parts in addition to the cost of the head and exhaust manifold. Don't forget new head bolts.
I R&R'd one head on my 2003 GMC sierra 6.0 LQ4 for the same reason - broken off exhaust bolt - driver's side very rear bolt - and it took me 8 hrs from start to finish my first time laying hands on an LS engine. I'm a diesel mechanic, but I think you could handle it if you were willing to work on an S-10 in the manner you did.
If you want to attempt replacing the parts yourself you're probably looking at 1 days work and about $100-$150 in parts in addition to the cost of the head and exhaust manifold. Don't forget new head bolts.
I R&R'd one head on my 2003 GMC sierra 6.0 LQ4 for the same reason - broken off exhaust bolt - driver's side very rear bolt - and it took me 8 hrs from start to finish my first time laying hands on an LS engine. I'm a diesel mechanic, but I think you could handle it if you were willing to work on an S-10 in the manner you did.