'06 H3 Adv, 110k miles on Mexican roads, I have 2 questions that I hope someone can help me

1.- For an H3 with this mileage what's the recommended oil viscosity?

2.- Is there any way to prevent water from getting in to the cabin when fording deep waters? like making door seals stronger?

thanks in advance!

 

water that deep will get inside the doors and start rusting. also probably reach other more important stuff underneath,tranny,transfer case, engine stuff.

oil,? years ago i used 10-30 or 10 40 on high mileage engines but dont know how the i5 would like it. it gave higher pressure,,,for a while!

 

Oil... Everyone has an opinion on this stuff. Here is mine. 110k miles is not a lot of miles for an '06 providing the vehicle has had regular maintenance. The heat on the Mexican roads can take a toll on oil. I have a 28 year old Toyota V6 with 300k miles and run 5w30 in the winter (Canadian resident), 10w40 in the spring and fall and 20w50 in the summer. Keep in mind that the engine in the old Toyota is completely different from the I5 in the Hummer. Timing chain instead of a belt, variable valve timing and tighter tolerances in the I5. There are some tiny ports for the variable valve timing. I suggest you run a full synthetic 5w40 in the Hummer and change the oil every 7500 miles. 20w50 would be way to thick at start up and 5w30, although recommended, can't take the heat. You need a thinner oil on startup, a thicker oil to deal with the higher temps and the synthetic won't break down as fast as conventional oil.

Now about the water... Tuck tape the door to the body and climb in the window. But seriously I would be more concerned about the engine, transmission and drive line parts becoming contaminated with water. I would also be concerned about anything electrical becoming swamped with water.

 

The interior can be dried out, remember to re-route the breather lines from the transmission and differentials. Remember, if you can get water inside the cab, the BCM is not much farther above the level of the door seals (below the glovebox, behind the right kick panel). You don't want that getting wet at all.

 

at least one module under the driver seat under carpet.
if you dont pull carpet the floor will forever rust

 

I didn't find a module under the driver's seat, but there is one for the airbag under the center tunnel below the arm rest.

 

Thanks for the help! I used 5w30 full synthetic.

And a fun fact now that you say you consider 110k miles is not much... in México (we use kilometers) 160k+ km (100+mi) is considered a high mileage car, most people swap cars after 5 years or 60k miles (in my family we do every 3-5 years) This is because we don't travel long distances and we do mostly less than 55 mph on our roads. The average healthy car here travels about 15-20,000 km a year, any more than that per year is considered overuse and no good for the car (for example a 2013 with 80k km or 50k miles is not good and people avoid buying them)... thats 10-12,000 mi/ year. My dad's car for example did less than 9,000 miles in a year with daily use. A car with more than 160k miles is rarely seen rolling unless is very good preserved or its definitely a rolling piece of scrap metal with 15+ years old.
The thing is the engine stays on for longer intervals of time and travels less distance. Many people say a Canadian/US car that has 100k miles is like a mexican car with 100k Kilometers (60k miles). Our climate also affects, in my city on winter we are 30-45 Fahrenheit and in summer we are 95+ reaching sometimes 110. We sometimes have 65º temperature changes in less than 24 hours. Thats why I was asking if my engine needed a different oil.

 

after warmup they all run at 195 appx from the equator to canada!
your engines are probably healthier as they go thru less temp swings than
up north starting at -30 at times.

the thermostat is the temp boss!

they are made to run hot best.