Chevrolet Colorado & GMC Canyon Forum banner

1 - 20 of 27 Posts

·
Registered
Joined
·
20 Posts
Discussion Starter #1
Hello,

Glad to find some Colorado junkies...my son has 2004, 3.5 with 130K miles. Started running rough on him several months back. Recent compression check has #3 cyl at 40psi. Truck feels fine above 2500RPM, but nasty rough/vibration below due to 4 outa five working. I'm almost positive he has the 3.5..will check tomorrow.

I did Google search which ended up leading me here. I am now aware of "the problem" these years have with valve seats. so I have a few questions;

Is it better to swap head or look for low mileage engine?? My concern with used engine is same problem down the road with any 04-06 head. Will a later year engine swap in, 07-09??

Should I get a head and have them do seats, or is there a better head/improved that will work?? MY guess is machining the current head will be the least expensive....

How tough is it to R&R the head?/ I have built and worked on small and big chevy V-8's...Mazda Miata 4 banger, but NO Isuzu engines. Am I getting into a can of worms, ie special tools, etc?? Anyone who has done this have any pointers, and about how long for a first timer under the hood of the mighty Colorado??

Any advice is greatly appreciated. he's coming home from school for 10 days on the 18th, so we would like to "git 'er done".

Thanks again, Bob 940-902-1266
 

·
[MTS] Who is this guy?
Joined
·
3,779 Posts
@540 Olds If you can work on the engine yourself the cheapest way to go would probably be to do get the head repaired. However, something that many of us choose to do is to just swap in the 3.7L i5 from 2007 and 2007 only. The general consensus is that it is around the same or only a little more money to get an 07 3.7 and do the swap as it is to get the head replaced/repaired (for most). And with the 3.7 you get an extra little boost in power.
 

·
Registered
Joined
·
20 Posts
Discussion Starter #3
Hi Skizzo,

Thanks for the reply. Do I need to swap the computer/ECM for the 3.7, or will ours work with it?

I'll check local junkyards for a 2007..3.7

From what I read on other threads, the engine swap is about a 20-30 hour project..is that correct??

Thanks again,

Bob
 

·
How d'ya like them apples
Joined
·
941 Posts
Hi Skizzo,

Thanks for the reply. Do I need to swap the computer/ECM for the 3.7, or will ours work with it?

I'll check local junkyards for a 2007..3.7

From what I read on other threads, the engine swap is about a 20-30 hour project..is that correct??

Thanks again,

Bob
if you need any parts, I would call Kenny. He is in College Station but he is always buying wrecked Colorados and parting them out.

Kenny - 979-436-6846
 

·
[MTS] Who is this guy?
Joined
·
3,779 Posts

·
Premium Member
Joined
·
3,316 Posts
It took roughly 6-7 hours to swap my motor out. If you have a engine lift and proper tools it shouldn't take to long and extra set of hands goes a long way too.


Sent from AutoGuide.com App
 

·
Registered
Joined
·
20 Posts
Discussion Starter #7
Thanks for info; no luck so far on locating a 3.7....also still trying to contact Kenny. GOnna try to get this done next week if I can locate parts.

Any other year engines for a direct fit??

Bob
 

·
Registered
Joined
·
20 Posts
Discussion Starter #8
Hi guys,

My son and I are trying to do this next week. No luck on locating an '07 engine he can afford. Salvage yard guys are telling me the '07 will not go in '04 as direct plug-in. You guys do more of this..

I did locate an '06 3.5 with 86K miles for $1300; my concern is having this head problem down the road again in 30K miles. Junk yard guy claims this head problem is with all years...my research shows it was the 04'-06 years..??


Looking for a head to put seats/valve job comes up fairly exepnsive compared to engine swap.

Since I don;t know these trucks/engines well, I am confused more than a little.
VIN is 1gcds 1367 4820 7204

ANy advice on what to do...buy the '06 and see how it does, or hold out for '07?? Is the '07 swap a direct plug-in?? He wants to get it on the road by mid November..

Thanks for any help,

Bob
 

·
[MTS] Who is this guy?
Joined
·
3,779 Posts
@540 Olds your best bet is to look on car-part.com for a 3.7 near you. You will find the best prices on there most likely.
 

·
US Army 19yrs and ......
Joined
·
45,284 Posts
@540 Olds If you can work on the engine yourself the cheapest way to go would probably be to do get the head repaired. However, something that many of us choose to do is to just swap in the 3.7L i5 from 2007 and 2007 only. The general consensus is that it is around the same or only a little more money to get an 07 3.7 and do the swap as it is to get the head replaced/repaired (for most). And with the 3.7 you get an extra little boost in power.
^^ this is the way to go
 

·
Registered
Joined
·
20 Posts
Discussion Starter #11
Okay,,

We decided to pull head and have it repaired; couldn't find engine at reasonable price. I've been all over the internet reading up on this head swap job...advice and info seems all over the map. We

We have almost everything off, but the INTAKE manifold is a PITA...can't get to valve cover or head until this off. We pulled drivers side tire and inner plastic fender to get to the bracket on the side of the intake. Appears we have it loose after finding the three hidden bolts, but cannot get it out of the way enough to see if there are bolts behind it.
Got alternator loose and out of the way to get to bolts on front end. Both fuel lines leading to regulator have been dis-connected. Exhaust manifold is off

The ones behind the fuel line/oil dipstick bracket are the bolts I can't see or get to for now. Anyone know the secret to getting this bracket off?? I can't tell if it's just attached to some "fir tree" plastic wire holders or what's holding it. It's very loose, but still not willing to slip out of the way.
,
Couple questions at this point;

How many manifold bolts are there?? I have read "two per runner", but I don't see two in between each runner.

Do we need to pull the starter to get intake off??
Once we get to the head, can we re-use the factory bolts??

If any of you have done a lot of these and have a few minutes, please PM me and I'll send my number. I was hoping to have the head off this afternoon, but it's still attached as of 7:41 CST... we started at noon...Not havin fun right now.

Thanks, Bob
 

·
Registered
Joined
·
70 Posts
Hi Bob,

I don't know for sure but I'd guess the head bolts are "torque to yield" and you'll have to replace them, based on the amount of bolt sets available.

Here's a pic of the intake manifold for bolt locations:

 

·
Registered
Joined
·
20 Posts
Discussion Starter #13
Thanks for the pic..we went back out and figured out which bolts we were missing...managed to get that damn bracket out of the way and got down to the head..

WHO the hell put ALLEN BOLTS on these things??? Of course you find this out after all the parts stores have closed !!

Sometimes I'd just like to call the enginers and ask "what the hell were you thinking" when you work on some of these cars. I'll have to go and get a real 1/2 socket with an Allen head on it tomorrow morning...

I brought engine to TDC by lining up the cam "flats", and watching the "rising screwdriver" in the #1 hole, but I didn't notice any real indications on the cam gears to tell me I was Top Dead Center...Did not remove any gears or chain...yet

FWIW, we did NOT pull the starter to get intake off..Once we got that bracket out of the way, we could get to all the bolts. We did have alternator off to get to front bolt.

THanks again, Bob
 

·
Registered
Joined
·
20 Posts
Discussion Starter #15
Thanks again for the timing chain pic..we removed sprockets and let chain go...took radiator and all the front end stuff out of the way...

PROBLEM #1000; all 15 head bolts are out, but head is not coming off. It will come loose in back and rock side to side in the front, but it is pivoting on something in the front on the "drivers side" of the head. We tried gently prying and attempted to use a lift, but it's tight enough that you can begin to see engine come up with head still not coming off.

anyone have any idea what could be sticking on the front side of the head?? We can't see anything attached; it rocks around, but seems stuck on something. Only thing we are thinking is there are some sort of covers to get to the bolts holding the cam guides on inside the head..??

Any info would be helpful...Thanks again,

Bob
 

·
Registered
Joined
·
1,394 Posts
The block has 2 alignment dowels for the head, you're piviting it on the front dowel. It has to come straight up or it will be a bear

Edit: also there are 3 10mm bolts in the head where the timing chain is. You can se the theads for the bolts in the block pic below.
 

·
Registered
Joined
·
20 Posts
Discussion Starter #18 (Edited)
Ok..finally got it off; somehow, the chain guide on the dirvers side broke and was causing the hangup. one of the intake valves on #3 cylinder had a chunk missing about the diameter of a pencil....Other valves and all cylinders looked okay, so it's off to City Motor Supply tomorrow.

Thanks for the advice and pics...now we get to re-assemble next week sometime..I can't wait for that fun.!!

Bob
 

·
Registered
Joined
·
1,394 Posts
Make sure you lubricate the crap out of the head bolts, they will break when torqing them down if they arent.
 

·
Registered
Joined
·
1,669 Posts
Ok..finally got it off; somehow, the chain guide on the dirvers side broke and was causing the hangup. one of the intake valves on #3 cylinder had a chunk missing about the diameter of a pencil....Other valves and all cylinders looked okay, so it's off to City Motor Supply tomorrow.

Thanks for the advice and pics...now we get to re-assemble next week sometime..I can't wait for that fun.!!

Bob
hey bob where are the pics?
 
1 - 20 of 27 Posts
Top