I just got a Duramax at a auction for what I thought was a good deal. Turns out I got screwed. I have a large amount of problems and I have no idea how to fix them.

1. Engine always says low coolant. When I add coolant to the point where it stops saying it the fluid will drain out after I run it.

2. After a rain water falls from somewhere and lands on top of the dash and floor

3. The air conditioning is all jacked up. Only the driver side will blow cold air, but the passenger side will blow very warm air. I fixed the resistor under the dash an that fixed the blower speed control, but nothing else

4. The rims are trashed and the tires are bald. I pull a 6 ton John Deere around almost very day so I need quality parts, but I don't have a lot of money. Does anyone know of a aggressive tire that is inexpensive with inexpensive wheels?

5. When I am at idle something under the truck rattles a lot, but as soon as I tap the gas it goes away.

Any help is appreciated. Thank you!

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Also thinking about putting a PCV reroute kit on and a cat delete pipe and possible a small tune due to how much I pull. What does the PCV reroute do and is it worth it? Any help is much appreciated. Thank you!

 

1. possible head gasket issue
2. use a garden hose to locate the area
3. may need to replace the climate control (HVAC module), or you may have more wiring issues
4.Falken Rocky Mountain ATS tires - Reviews, ratings and specs in the Sacramento Area - Discount Tire/America's Tire
Wheel Products By Vehicle - Discount Tire
5. this one you should be able to find.

PCV reroute over hyped? - Diesel Place : Chevrolet and GMC Diesel Truck Forums

 

3. There are multiple actuators behind the dash that control the flow/temp of air... Could be one of those as well

 

My LLY had the same issue with the ac. Its most likely a stuck damper motor not to bad of a repair as long as you find the right damper. Get an exploded view of the hvac on the truck and it will show you the locations. As far as the leak I'd say the windshield gasket unless it has a sunroof. If it has a sunroof check the drain tubes. As far *** the tires it deends on how aggressive you want them, All terrain or off road? I've had good luck with BFG all terrain KO's and Nitto Mud Grapplers. If you want towing and decent road manners out of them I'd say the BFG's. As far as wheels look on Craigslist or classifieds on some of the forums could probally get a good set of PYO's or some aftermarket rims pretty cheap.

 

Hey buddy have no fear you didnt buy a lemon, dont get me wrong it sucks about the rims and tires but the other issues really arent a big deal. Starting with the coolant problem, The issue is a faulty coolant level sensor. When people neglect the cooling system the float on the sensor ends up sticking. just replace the sensor in the jug, fill it to the correct level on the outside of the jug and you'll be fine. as far as the heat goes the part you need is the passanger blend door actuator. these things were pieces of **** from the factory. To get to the pass side one you need to swing the glove box door all the way down. To do this open the box take all the stuff out in the back corners there are stops that keep it from flopping out pull them in toward the center of the box and pull out gently. the actuator is located on the left hand side above the heat and ac box. three 7mm screws hold it in. IMPORTANT. if your model is a digital temp as opposed to manual do not plug the new actuator in until it is installed. if you do it will screw up the position sensor inside the actuator. Now as for your water problem I am 99% sure this is due to one of two things. Either you have cab lights that were installed aftermarket and they are leaking or the windsheild has been replaced and they were sloppy and didnt seal it correctly. To check the windshield get a can of soap put it around the edges of the windshield go on the inside and use compressed air go around the edges and have someone look for bubbles. If found have a local windshield shop re-seal or replace it. The rattle under the truck is completely normal dont sweat it. I highly recommend the Cooper Discoverer STT tire if you want a quality agressive tire. Call your local salvage yard for wheels that will prob be the cheapest. the 2000-04 offered a steel with crome covers made on them. you can usually pick them up around 100-125 each. Good luck with the truck, I dont think you have anything to worrie about these are quality trucks.

 

Jshannon pretty much summed it all up.
Nobody's really addressed the PCV reroute question. The Positive Crankcase Ventilation Reroute modification is pretty easy to do. These are the rubber lines coming out of the top of your valve covers. You could probably try this one yourself if you feel like laying under the hood for a while. Basically you take those hoses off of the valve covers, block off the other opening. (beside the alternator bracket, front of engine, i think) Then, you take two longer hoses, make sure they are fuel/oil proof, and run those out of the valve covers, over the top toward the passenger side, and all the way down. past the cab, to dump on the ground.

What this will do is just aid in helping your engine run cleaner. Normally, crankcase ventilation lets gasses from combustion that passes the piston rings escape and get recycled into the intake. What this mod does is let the gasses out, but not back into the engine. HOWEVER, you may notice that your oil level goes down a little. That is normal with this mod.
Don't expect a huge gain with this, I probably wouldn't even worry about it, until you do a lot of other airflow, intake, exhaust, and tuning mods.

 

coolant levels are head gaskets. My brother had an lb7 with the same thing. His low collant light came on. Filled the resivor up. 2 weeks later the light would come on. He added about 2 bottles of stop leak over a peroid of about 3 months and it helped but didnt completely fix it. LLY's are known for head gaskets to go because of the high compression.

 

I recently picked up a one owner low mileage duramax fully loaded 05'. Well I had the leaking from above the windshield too. Unfortunately it was from the cab clearance lights on top. The sheet metal had rusted clean through under the lights. Not visible without taking the lights off. I hope this is not your leaking problem. I had to cut it out and replace the sheetmetal before repainting....

 

Coolant light could be head gaskets. not always. usually they blow coolant out the cap, then you're sure it's heads. Sometimes there is a crazy little coolant leak by the water pump. Sometimes small enough that it evaporates before it gets to the ground. So, just checking for drips on the floor isn't enough. Look down around the water pump. the bottom weep hole is visible from the driver's side, through the fender well. May have to remove the inner liner to see it clearly.
Make certain that you don't have any external leaks before you condemn the head gaskets. You could save yourself like 3500 on the head job, vs a few hundred for the water pump or other leak fix. If you plan on having the heads done... DO NOT put any "silver seal" crap, or any other "head gasket in a can" crap in your engine. It will plug your heater core... that's not cheap either.
Head gaskets.... oh boy, sounds like fun. We usually sell rebuilt heads and check the customers' to determine if the cores are good. That way we can do it all at once. You should try for that. Don't want to wait on the machine shop. I'd also suggest some head studs and good MLS gaskets from GM. Studs don't fail.
Regarding your climate control.... sounds like a broken door or motor in the HVAC unit.
Hope you get stuff cleared up.