Hey I bought an H3 a few months ago and I have had a few issues / questions I need some answers to.

1.) Does the H3 come with any underbody protection? I have seen some OEM and aftermarket stuff out there but I'm curious if any of it came stock on the H3. I just notice some bolt points for something like that when I was changing the oil the other day and was curious if the previous owner took it off.

2.) Do all H3's sway in windy conditions? Its seems that when I am on the interstate and its windy or when a semi passes me that my H3 sways pretty bad. I know its not the most aerodynamical vehicle but I didnt know if something else could be going on with it.. (I.E. shocks going bad, anti-sway links going bad, etc.) I have never driven another truck or SUV that sways this bad and the H3 is a fairly heavy truck for its size.

3.) Rear seat belts where wet after a storm. From what I have researched this is because the sunroof drains are clogged and I need to spray them out with an air hose. Can anyone confirm this?

4.) My H3 has 265's on it... they look too small for the truck and according to the owners manual, they are. Which explains my speedo being off. Suggestions on tires?

5.) Lastly, It has thrown the P0300 and P0128 code multiple times since I have owned it. I'm working through this one. From what I've read, I need to clean the MAF, put new spark plugs in and replace the thermostat and temp sensor. When changing the thermostat I know I need to drain the coolant. Are there any air bleeds I need to be concerned with? Dont want to fry a water pump or something due to air bubbles.

Thanks for the tips. Feel free to just drop me links to other threads that may help me out.

 

To change oil there are two plates that must be removed,yours must be missing.
My h3 has no sway at normal speeds and actually corners very well on a twisting road.
There was a post with pix of the rear drains,somewhere here...search.

I had a h3 with 265 tires,now have 285 and i cant get 20 mpg on trips like I did with 265s.??? 265 are stock on some h3,285 on others, both ok.
#5,dont know??

 

1. The H3 comes with some underbody protection but it is minimal. That is the reason for the additional OEM protection and aftermarket.

2. The H3 has a lot of sail area and a relatively high center of gravity so it is going to be affected by a side gust more than a vehicle with less of both.

4. Most H3's came standard with the 265's, only the Adventure models came with 285's. Anyone who suggests a tire without knowing what kind of driving you want to do is just blowing smoke.

 

100%, I couldn't agree more!



daiglesbagels, please take the time to do a little research on this forum by using the "SEARCH" function on the top of each forum page. Most of your questions have multiple threads dedicated to them with great insite into the issues.

As for the sway in windy conditions: Yep, the wind catches ya and can whip you around. But, just like any vehicle issues you learn to deal with it and drive accordingly or sell it because you don't want to deal with it. We drive a brick on top of a larger brick. Flat sides all the way around.

 

Thanks for the insight! I would really like to know what the undercarriage on an H3 looks like so I can see these plates that I am missing. Haven't been able to find a pic of one anywhere on the internet. All of the images show modified undercarriages but no stock undercarriages.

As far as the tire size, since mine calls for the 285 light terrains from the factory I am guessing its an adventure package? It also has the rear lockers which I have yet to try out.

I am consistently getting 15.5mpg (which is probably more like 14.5mpg due to my speedo being off) in mixed commuting driving and was hoping for something closer to 17-18mpg. My driving mix is about 95% commuting and 5% light trail.

 

These are the only photos I have and should give you some idea, you can see no protection in the middle, and you can see the front bash plate, there is also a small plate that can be seen.



Here is the small plate:



Here is the genuine GM underbody protection you can fit as an optional upgrade, picked this up on eBAy quite cheaply:



Here it is fitted:





Hope that helps.