Sorting out your own LBZ thermostat plus cooling issues
If you've noticed your temp gauge acting a bit wonky recently, it might become time to take the closer take a look at your own lbz thermostat setup. For all those of us running the 2006 to 3 years ago Duramax, we know these trucks are absolute workhorses, yet they aren't specifically immune to the periodic maintenance headache. The cooling system any of those places where you really don't want to reduce corners, especially when you're using your own truck for exactly what it was constructed for—hauling heavy trailers or pushing by means of long highway kilometers.
It's pretty common to observe these trucks begin to run a small hotter than usual once they get some age on all of them. Or, on the flip side, you might find that the heater is barely lukewarm in the middle of January. Both of these types of problems usually stage straight to the particular thermostats. And indeed, I said thermostats plural, since the LBZ is a bit of an unique case with the dual-thermostat design.
Why does the particular LBZ have 2 thermostats?
In case you're coming from a gas engine or an old diesel powered, seeing two thermostats in one housing might seem like overkill. But there's a strategy to the craziness. The engineers with GM designed the 6. 6L LBZ to maintain a quite specific, stable working temperature. By using two units, the engine can regulate coolant flow much more specifically.
Usually, you've got one thermostat that starts opening at around 180°F and another that follows suit with about 185°F. This particular staggered opening stops a massive "slug" of cold coolant from rushing into a hot motor all at as soon as, that could cause thermal shock. It maintains the temperature transitions smooth. When one particular or both of these start to fail—whether they're stuck open, stuck closed, or just lazy—your engine's performance goes right away the window.
Signs your thermostats are on the way in which out
The most obvious sign is the particular temperature gauge upon your dash. If you're cruising straight down the flat road and you observe the needle dancing around or sitting significantly less than the "normal" 210 tag, one of your own thermostats is most likely stuck open. Whilst a cool motor might sound like a good thing, it in fact hurts your gas economy and helps prevent the oil from reaching the correct viscosity. Plus, your cab heater will certainly suck.
On the other hands, if you're viewing temps climb past 230°F while you're towing a moderate load, you've probably got a lbz thermostat that will isn't opening just about all the way. This is the dangerous side of the particular coin. Overheating a Duramax can lead to blown head gaskets or bended heads, and nobody wants to deal with a fix bill that high.
Another subtle sign is definitely a drop within fuel mileage. If the ECM (Engine Control Module) feels the engine is still cold, it'll keep dumping even more fuel to try out and take it up to operating temp. If you're instantly getting 12 MILE PER GALLON when you used to get 16, check your statistics.
Picking the particular right replacements
When it comes to buying a new lbz thermostat set, you've obtained choices. Lots of guys swear by the AC Delco originals. Honestly, it's difficult to argue with that will logic. The factory ones lasted one hundred fifty, 000 miles, therefore why wreak havoc on achievement? They're reliable and built to the precise specs of the particular housing.
However, if you live in a particularly sizzling climate or you're pushing big horsepower numbers with the tuner and larger injectors, you might look into high-performance options. Brands like Mishimoto offer thermostats that open in slightly lower temperature ranges. This can give you a little more "headroom" before the motor gets too very hot under heavy load. Just be careful—if you go too cool, you might induce a check motor light because the particular truck thinks it's taking too much time to warm up.
Tips for the particular swap
Replacing the thermostats on an LBZ isn't the hardest work in the entire world, however it can be a bit of a literal "pain in the neck" because of exactly where they're located. You'll get the housing ideal at the top entrance of the engine. Here are a few things I've learned from doing this a couple of times:
- Drain the coolant first: You don't need to drain the entire radiator, but a person want the amount reduced enough so that whenever you pop the housing off, you don't get a gallon of Dex-Cool throughout your serpentine belt.
- Watch the bolts: The particular bolts holding the particular thermostat housing may be stubborn. They've been through thousands of heat cycles. Make use of some penetrating oil and take your time. If you snap one of individuals off in the particular crossover bridge, your Saturday will probably obtain a lot more.
- The particular "Jiggle Pins": When a person drop the fresh thermostats in, make sure the "jiggle pins" (the little valves that allow air through) are usually facing toward the front from the pickup truck or upward, based on the particular orientation. This helps prevent air pouches from getting trapped.
- Clean the mating areas: Don't just slap the particular new ones within. Use a plastic scraper or a few Scotch-Brite to obtain the old seal residue off the particular housing. A clear seal is the particular difference between a dry engine plus a slow drip that will drives you insane.
The have trouble with air pockets
The biggest headaches after installing a new lbz thermostat is "burping" the system. Duramax engines are well known for trapping surroundings in the cooling system. In case you simply fill up plus drive off, a person might see the temp gauge spike almost immediately. This is because a good air bubble is definitely sitting right contrary to the thermostat, preventing it from sensing the particular coolant temperature.
The LBZ has a bleeder screw on top of the thermostat housing (usually a 12mm bolt head). While you're refilling the coolant, maintain that screw loosely until a stable stream of coolant starts coming out without having any bubbles. Even after that, I usually prefer to park the truck on a slight incline with the nose upward, let it operate with all the cap away from for a bit, and maintain an eye for the overflow tank.
Is it well worth doing yourself?
When you have a simple set of electrical sockets and a few of hours, you can absolutely do this in your driveway. It saves you a couple 100 bucks in labour at a store, and you get the peace of brain knowing it had been done right. Simply make sure a person use high-quality coolant—sticking with the fruit Dex-Cool or a high-quality "all-vehicle" diesel coolant is generally the way in order to go.
While you're in there, it's the great time to inspect your rad hoses and the serpentine belt. Since you're already moving points around, you may simply because well replace the bulging hose now rather than waiting for it in order to burst quietly of the interstate.
Wrapping it up
At the particular end of the day, your lbz thermostat place is a fairly cheap part that will plays an enormous role in the long life of your engine. It's one of those "while I'm at it" maintenance items that really pays off. Whether you're trying in order to get your heating unit working better for that winter or you're prepping for the cross-country haul with a heavy truck, making sure your cooling system will be up to par is essential.
Keep an eye on that gauge, listen to how the fan clutch is participating, and don't disregard the small signs of a failing stat. Your Duramax will thank you with another couple 100 thousand miles of reliable service. It's a simple fix that keeps the particular heart of the vehicle beating just the right temperature, plus honestly, that's one of the best ways to ensure your LBZ remains on the highway for many years to come.