Hi everyone. I own an 07 H3X with the 3.7 I5, but I had a shower thought question wondering which H3 engine was the most reliable.

So, in your opinions, which engine is the most reliable? 3.5, 3.7, or 5.3? I would imagine the 5.3, but I don't know. I'd be interested in buying an Alpha if they weren't so expensive!
Also, since they are much bigger engines, and being a V pattern engine, are the 5.3s harder to work on than the I5s? And do they have the cylinder deactivation/displacement on demand?

Thanks,
Isaac

 

i5 is not a reliable engine. This is a stripped down engine from the I6. Just a bad cooling system with a bottom thermostat. This leads to overheating and engine failure. V8 is much more reliable.

 

There is nothing wrong with the I5s, there are many still running around with well over 200K miles. I5s do not have any "overheating" problems and BS is called. They have common issues, overheating is not one of them.

I do agree that the 5.3L is a long standing reliable motor, but they too can have issues.

 

Disagree about good cooling. A very small radiator for such a motor (from the same on the V8 5.3).
No engine oil cooling. The lower thermostat does not work efficiently (this problem is for many engines with such a thermostat installation, for the same ZD30 for Nissan, the same problems).
It's fine while driving, but when parked in extreme heat it's a problem. Moving the thermostat to the top, replacing it with a large radiator and electric fans solve this problem.
If you live where there is no heat, then this is not a problem.

 

 

Chevy 5.3 V8 is a much better, more proven engine and is still used on the 2023 Silverado’s, Tahoe’s and Suburban’s

The biggest issue Chevy had with the 5.3 or any of the V8 truck engines is when they implemented that stupid Active Fuel Management System where it turned off 2 cylinders for better fuel economy.

 

Actually, the I5 is half of a V10 that GM had built for a mid-engined supercar that got shelved. When they upgraded the 3.5L to the 3.7L, they added more stuff from the V10, like four-valves per cylinder, computer-controlled variable valve timing, a higher compression ratio, and a bunch of other stuff.

 

What are you talking about??? The i5 is a stripped down engine from the Chevrolet TrailBlazer 4.2. There were three types of I5 engines in total. 3.5, 3.7 -2007 and 3.7 - after 2008.
The best - 2007. Two camshaft sensors. There is a chain loosening control. One computer for automatic transmission and engine. It's easier to reflash.

 

Nope.

You really believe they chopped-off a cylinder from the straight six? That would be some feat of engineering. Not to mention, where'd they get the heads with four-valves per cylinder, and the computer-controlled variable valve timing, and numerous other stuff, which was never on the straight six?

 

Quote:

Originally Posted by Disel

i5 is not a reliable engine. This is a stripped down engine from the I6. Just a bad cooling system with a bottom thermostat. This leads to overheating and engine failure. V8 is much more reliable.

Quote:

Originally Posted by Disel

Disagree about good cooling. A very small radiator for such a motor (from the same on the V8 5.3).
No engine oil cooling. The lower thermostat does not work efficiently (this problem is for many engines with such a thermostat installation, for the same ZD30 for Nissan, the same problems).
It's fine while driving, but when parked in extreme heat it's a problem. Moving the thermostat to the top, replacing it with a large radiator and electric fans solve this problem.
If you live where there is no heat, then this is not a problem.

Quote:

Originally Posted by Disel

What are you talking about??? The i5 is a stripped down engine from the Chevrolet TrailBlazer 4.2. There were three types of I5 engines in total. 3.5, 3.7 -2007 and 3.7 - after 2008.
The best - 2007. Two camshaft sensors. There is a chain loosening control. One computer for automatic transmission and engine. It's easier to reflash.