Motor replacement options....

[4speedfunk]

I have several customers that are looking for motor swap info on their H3's. Nearly all of them have experienced:

-oil pressure warning lights
-random misfires
-failed compression tests (one or more cylinders less than 80psi)
-oil in the intake
-leaking front and/or rear main seals
-blown head gaskets
-bottom end knocks

These problems seem to occur between 150k to 300k miles, and they happen to both the 3.5L and 3.7L motors. Obviously we all know by now that these L5 motors are complete crap. If anything ever happens to my L5, I would not even waste time fixing it. Being an experienced gearhead with a shop, tools, and resources, I would certainly go for a 6.0L V8 swap or even a diesel swap. But, these customers are looking for stock (cheap, fast, and simple) motor fixes. Most don't have the budget, time, or knowhow for a custom swap. And also many of them live in strict emission-testing states that make custom swaps impossible. So, my specific questions are related to repair or replacement of the stock L5 motors.

Has anyone swapped a 3.5L out for a 3.7L?
What all is involved with this? (sensors, PCM, etc.)
Is a 3.7L really any better than a 3.5L?
Where is a good place to get a rebuilt L5?
How different are the Colorado/Canyon version of this motor?
If you've done an L5 head gasket or motor rebuild...love to hear about your before & after experience.

Lastly...as soon as I say "motor swap" on the internet, the conversation immediately goes into mega-buck V8 land. Please keep this thread limited to stock L5 swaps. Any info on these turd motors is appreciated.

 

[Happy Hummer]

Quote: "looking for stock (cheap, fast, and simple) motor"

These 3 are not really possible. Cheap? Not!
Pull engine? At current labor (approximately $200/hr.)

The kkb value of a 07 hummer h3 in decent/great shape $7k - 10kish. Thats with lower miles.
Rebuilt or used engine? At current price (approximately $1,900 to well past $5k)

 

[Happy Hummer]

The hits keep coming. As, we own a 3.5 or 3.7L gm engine. A engine disowned and a line of vehicles they (gm) would very much like to forget.
So, if you do achieve the swap and the customer pays (well north of $7k) your left with a suv that you can't purchase a freakn door seal for.

I applaud the desire to keep the 'ol gals going but the end of the road (junk yard) is harkening. Well at least in rust belt .

 

[wpage]

There are choices and options out there...

From the looks of things a swap out for a rebuild may be the best decision for some.

 

[cgalpha08]

CJ. Badlands industries out in Nevada rebuilds them. Not sure the price, but 4-5k i think? Might be the easiest way to get a direct swap in without monkeying with anytbung significant

 

[08H3]

4Speed had texted me on this as I fall into this category. Unless you are deep into a truck money wise, I just don't think it can be done. One of the engines his customer was considering was $5000 shipped. I paid $5500 for my most recent H3 with just a shade over 100k miles. I literally got the rest of the Hummer for $500. I think there has to be an emotional factor or a lot of money already in the truck. I don't think you can make it work financially.

In my case, I now have 3 H3s. I don't want anything bad to happen, but if one of them gets totalled, rusts away or whatever, then I have an engine I can swap.

 

[rascole]

4Speed had texted me on this as I fall into this category. Unless you are deep into a truck money wise, I just don't think it can be done. One of the engines his customer was considering was $5000 shipped. I paid $5500 for my most recent H3 with just a shade over 100k miles. I literally got the rest of the Hummer for $500. I think there has to be an emotional factor or a lot of money already in the truck. I don't think you can make it work financially.

In my case, I now have 3 H3s. I don't want anything bad to happen, but if one of them gets totalled, rusts away or whatever, then I have an engine I can swap.

It's all a matter of perspective, $5000 for a motor that was hand built with more care and caution than a factory motor will likely run for 200k and outlast the rest of the car. $5500 for a used car with unknown history might last a year or two. He has one car with a solid motor, you have 2 cars with suspect motors. If you like the H3 and plan on keeping it a long time, a rebuild is the cheapest option, but I get it that sometimes you just need to cut bait and move on.

 

[08H3]

I don't think getting a rebuilt motor is any guarantee of quality at all. I've seen some really poor remans firsthand. Also disagree with the assumption that a used car will only last a year or two. That said, I understand your point. Gotta' do what you feel is right for your situation.

 

[2dr_h3]

I have several customers that are looking for motor swap info on their H3's. Nearly all of them have experienced:

-oil pressure warning lights
-random misfires
-failed compression tests (one or more cylinders less than 80psi)
-oil in the intake
-leaking front and/or rear main seals
-blown head gaskets
-bottom end knocks

These problems seem to occur between 150k to 300k miles, and they happen to both the 3.5L and 3.7L motors. Obviously we all know by now that these L5 motors are complete crap. If anything ever happens to my L5, I would not even waste time fixing it. Being an experienced gearhead with a shop, tools, and resources, I would certainly go for a 6.0L V8 swap or even a diesel swap. But, these customers are looking for stock (cheap, fast, and simple) motor fixes. Most don't have the budget, time, or knowhow for a custom swap. And also many of them live in strict emission-testing states that make custom swaps impossible. So, my specific questions are related to repair or replacement of the stock L5 motors.

Has anyone swapped a 3.5L out for a 3.7L?
What all is involved with this? (sensors, PCM, etc.)
Is a 3.7L really any better than a 3.5L?
Where is a good place to get a rebuilt L5?
How different are the Colorado/Canyon version of this motor?
If you've done an L5 head gasket or motor rebuild...love to hear about your before & after experience.

Lastly...as soon as I say "motor swap" on the internet, the conversation immediately goes into mega-buck V8 land. Please keep this thread limited to stock L5 swaps. Any info on these turd motors is appreciated.

Man am having same issues about swapping my Engine. My i5 just took a crap, the bad thing is that my Hummer is a 06 i guess 06-07 are more of a hassle to swap to LS engines. I have a guy selling me a 6.0 of of a 2500 silverado and a 4x4 6l35 from a silverado aswell he also has motor mounts and other items needed for swap but idk if all the wiring will work ..

 

[4speedfunk]

All great comments. Looks like I should just pull one apart...see what failed...rebuild it myself...put it back in. Probably the cheapest, highest quality fix available. Plus, there would be no need for chasing down swap parts, since I would be going back with exactly the same parts I took apart.

 

[wpage]

Probably

If you have the tools and the skills. Go For It....

 

[rascole]

All great comments. Looks like I should just pull one apart...see what failed...rebuild it myself...put it back in. Probably the cheapest, highest quality fix available. Plus, there would be no need for chasing down swap parts, since I would be going back with exactly the same parts I took apart.

Usually the most logical decision, my 3.5 has gone over pretty much every obstacle I've aimed it at. But most of are not logical and are easily fooled by high horsepower, 1 tons, 44's and the guy that makes it look easily by doing the swap in his parents driveway. I fall into the later category.

 

[08H3]

I had posted this before, but last call. 2005 Colorado with a good 3.5 140K. It's headed to the scrapyard very soon if no takers. Not mine, but will get you in touch with the owner and facilitate to the extent that I can. Located in Indiana near Fort Wayne.

 

[pickledill]

In my opinion If you are gonna go through the work of replacing the engine you might as well go V8. You can get a wrecked alpha for a couple grand and swap everything over, but you could argue that you could just fix the alpha instead

 

[Doc Olds]

Thought I would just run down the initial complaint/problem list...

1-oil pressure warning lights: can be fixed, usually the sender or harness to it, but can be more complicated electrical issue. Oil pumps and pick-up seals do not last forever.

2-random misfires: happens often, usually can be corrected by an induction cleaning and sticking with quality top tier like fuel ALWAYS.

3-failed compression tests (one or more cylinders less than 80psi): could be more serious, or see #2 above.

4-oil in the intake: not an issue, happens with heavy skinny pedal use and a bad valve cover breather(s) being obstructed/gummed or goobered up.

5-leaking front and/or rear main seals: gasket kits or checking fastener TQ looking for loose cover bolts caused by I5 vibrations.

6-blown head gaskets: can be BAD, as in caused by overheating, but could be as simple as an OLD gasket that gave it up.

7-bottom end knocks: if it is not timing chain slap mistaken for something else, could be serious and need at least partial disassembly to inspect. This is the worst of the bunch.

Replacement I5 motors are hard to find and parts for a rebuild are getting that way too.

 

[Jeepwalker]

The I-5 engines aren't complete crap. Actually it's a rather high-tech engine, and quite a nice design. A few key weaknesses keep them from being great engines. Many owners have gotten well over 300k on them. The 5-cyl puts out a LOT more power than the ole Jeep 4.0 I-6 and more torque, better efficiency. But yeah, point well taken. They suffer from a couple weaknesses which can lead to the problems indicated above.

The oil pressure has been discussed above. The valves probably burn b/c of low oil pressure due to the pump/screen or bearings ....and therefore the oil-squirters don't cool the bottom of the piston (esp #3, when oil pressure is low) like they should. And it could also be from people using too thick of oil?? Regardless, it may lead to overheated cylinder and burned valves (low compression). But on the good: GM did use high nickle sleeves which often hardly need a honing, and some other high quality components inside (crank).

Too bad they didn't just figure out how to use the I-6. More power ...There's a ka-jillion of them out there! But I know the reasons they didn't (it's in "the book").

My engine has had 10psi oil pressure.... ha ha at it's lowest pressure ....probably for 10 years and 10's of thousands of miles?? And one cylinder is low on compression ...#3. I only discovered it b/c I went to check it out one time. The PSI goes up to 24-25 on the road. F-it! It runs just fine. I've driven it all over the country and done lots of trails in Moab and CO and been in the middle of nowhere and it's never let me down ...presumably in the same condition.

One day I'd like to pull it, and address just the basics as outlined above (new pump, bearings, replace burned valves, etc) ...not necessarily rebuild it. I've bought some of the parts already (rusty frame needs addressing first). Many owners have gone well over 300k mi with these engines. Nonetheless, lot of engines have problems, Hemi 5.7 lifters, Chrysler 3.6L cam followers... We could make a list of other engines which have issues.

Note, Per the pic below, once I bled the oil out of the gauge better, it went up to a bit over 10psi at the lowest. LOL

 

[Mr_Rich]

What I've learned in the last couple years has reinforced my opinion that the I5 is actually one of GMs better small engines. Mine never gave me any trouble for the most part. Throttle body, ps pump, and battery terms were replaced. I needed to add oil between changes after it hit 100K.

I thought the 3.6L was going to be the replacement if Hummer survived. What i know now is that I wouldn't want a vehicle with a 3.6L.
I loaded up an LS engine from my Firebird in the back of my 3T and managed to keep up with the speed limit on steep grades on 101. I sure couldn't do that in my 86 Jeep Comanche with the 2.8L V6. That was one of the better engines in its time but not a truck engine.