So the folks on LS1Tech.com dont wanna respond. Lookin for opinions.

While on the move and in gear, my car has no problem getting and maintaining heating for the cabin. Once I get the car out of gear, as in idling to a light or idling at a light, the car will no longer warm the interior of the car and the engine will start overheating. Is this indicative of a heater core, bad t-stat, or something I've yet to think about? thanks yall!

sounds like fans might not be coming on, have you checked that?

oh, there's plenty of air movement inside the cabin, so the blower is working. It's also not the blower resistor. Also the radiator fans do work. Thats why this puzzles me so. Thanks for the response.

sounds like a stuck thermostat

Either a stuck Tstat or a clogged heat exchanger.

is the heat exchanger the same thing as the heater core?

Will a system pressure flush restore the heat exchanger/heater core, or is a replacement required? Also, be aware that my interior is dry.

The tstat SHOULD be brand new. I had them install this thing when they replaced the engine. Guess I have a replacement to do, huh? The interesting thing is that the car warms up normally, and stays warm while on the move. Whatever. Tstat will be replaced this paycheck.

Thanks for the replies!

Stuck T-stat could be it. I've seen brand new ones stick...

Clogged coolent line somewhere? bad radiator? All Fluids up and full? Low fluids will give this same senerio.

Heat exchanger/core same thing

Just thought of something. Not enough cooling while at idle with fans on and no cabin heat?

Next time rev the motor and see if things improve. I wonder if you might have a water pump issue. Either a loose belt or pump starting to freeze up.

Check coolant level

Could be start of bad water pump.

w/p, got the check. Thanks. There has been a squeal in the bay. I thought it was the clutch fluid being BLACK black. But it did resurface today.

Tstat will be replaced soon.

Very certain fluids are up.

I have a year-old GatorBak on the car, so I am MORE than certain it aint my belt. I'm still running my NM GatorBak on the GP with NO signs of even a little wear.

I think I'm hearing to flush the system and see if that jars something loose. If not, I'm looking at heater core (thanks for that definition, Herc ).

Hey, all, for your replies and help:

It sounds like a partiall- plugged heater core for sure ,a good flush ma- do the trick other wise U will have to change ,did U ever use an- coolent stop leak? these products will plug up a cooling s-stem.Chico(pops)

Keep in mind if the flush doesn't work you may have to replace the heater core. If the tubing is lined with crud (think about a fish tank with algea all over everything) It may not come off with a flush. If that's the case the crud could insulate the tubing and not allow a proper heat exchange.

Chico: nope, never used any of that crap. After seeing what water does in a tire, and being told that No-Mor-Flat does the same thing, I vowed off of using clotting agents. What I will not say is that the previous owner did not use that garbage in the previous engine.

Herc: After the tstat (tomorrow), and the the flush (in about 2 weeks), would you recommend heater core first or the w/p?

Thanks gents.

Sometimes you can relieve system pressure and disconnect the heater core lines and just flush them with water from a hose. You need to flush in both directions a few times. My co-worker needs to do this every fall on his 2000 Chevy truck to get heat. He said he never sees anything come out, but he gets heat after each time he does it.

You might find after doing the flush that the water pump might get a leak. It happened to my '98 after a complete flush of the system. After driving 30 miles, sure enough, my water pump started leaking after the flush.

There's been talk (not here, but on the Cadillac forums) that you can use CLR in the heater core to remove anything that might be clogging it up. You have to take the hoses off the core and pour the CLR in the core and let it sit for ~30 minutes, then do a reverse flush with a garden hose to get all the 'gunk' out of it. I haven't tried it myself, but it might be worth a try and a lot cheaper than replacing the core.

As for the WP. Take the belt off and see how "freely" it spins. If you can turn it easy by hand I'd move on to the next item.

ok. just took a look in my cabin, and there was no coolant on the floor/in the carpet. My w/p moved very free, smooth, and quiet. Tstat was replaced already. No chocolate milk. Coolant full. What now? No, I dont have a puddle under the car. The belt is still good.

Like I said, the tstat was replaced. I then went to the heater core. That got the cabin warmer, but I was still overheating. I decided that it'd be a best to replace the rest of the coolant variables. Today, I replaced the ECT, radiator fans motors, and the w/p.

On the RWD L36, the ECT is right below the TB/MAF on the block. That was no problem at all, until I tried to torque the ECT down. I had no idea that the ECT has a tapered thread. No, I didnt damage the sensor, but something tells me I was about to.

The radiator fans motors were really simple. I had to remove the air intake system all the way back to the MAF, then lift the "tray" that holds the fans out of the claw-like retainers. By working one-handed, I was able to untether all cables and hoses from the tray and drop the tray from under the car. Once free, I carried the tray over to the work bench, removed the reverse-threaded nuts retaining the fan blades to find three bolts retaining the each motor (total of 2 nuts and 6 bolts). I dropped the new motors onto the tray, torqued the motors down, refastened the blade assemblies, and remounted the tray, re-tethered the cables and hoses, then moved onto the w/p.

Water pump was much easier than I anticipated. Four each 8MM bolts hold the pulley to the pump. 5 each 13MM and 4 (or was it 5?) 10MM bolts hold the pump to the block. Easy breaking the seal on the thing. Approach like you would a tranny filter, as once the seal is broken, coolant WILL flood out. Clean the gasket surfaces, line up the gasket to the bolts, start the thread by hand, finish by tool, refasten the pulley, route the belt, refasten the intake tract, bleed the coolant system, run the car to check for leaks, clean the bay, pay the cashier, and drive away into the sunset.

Thanks to those who offered their input, including, but not limited to Slick, Eric from work, Corey, and Karl. As I was clearing the bay, I asked the technician if I dialed in the cooling system if the cabin was burning at 200* while the engine was burning 185*. He chuckled.

"clean the bay, pay the cashier,"

I take it you utilized the auto-hobby shop on base?

is there any other way to go? lol! heck yeah! think I've spent about a quarter of a paycheck there in the last 9 months.

I changed my fuel pump on my truck in my driveway. Took the bed off and went to town.



Next project in the driveway is replacing the rear axle. The one that's on there now is so corroded it isn't funny.

after how many years in ME? Not a surprise. I used to do my own work in the driveway or parking lot, but since I lost a vast majority of my tools, I cant be doing that anymore.

Where'd you get the new axle? How much? What gears? What diff?

Six years in Maine. I'm going to grab one from a U-pull it. Iirc roughly $125 for a rear end. All the ones I looked at are in much better shape. Gears will be stock 3.42 and I'm thinking of adding in a power trax diff. Supposedly better then a posi but not quite a locker. That project is going to wait until after my Son's HS grad this June.

Here's what it looks like right now. Can't really see it but the rust flakes are 1/8 to 1/4 inch thick. Also looks like I lost a counter weight on the drive line. I'll get that replaced as well.

yeesh! nasty! Found a website for propeller shafts that sell aluminum for about half of a GM steel shaft. Interested? I can link ya.

Why not go to LSD while you're doin some stuff back there? I mean, you gotta change diff grease anyway, right? Might as well get some stuff done while back there and got the stuff outta yer way.

Shoot me the link for the prop shaft. The powertrax is a step up from a Limited slip but not quite a locker.

http://www.powertrax.com/powertrax/noslip.html


Oops just realized I highjacked your thread.

no issue with the thread jack. The thread's over anyway. I had a prob, got input, fixed, posted fix. Anything after that merely needs to be appropriate IAW board guidlines.

http://www.speedinc.com/cont.cfm?cid=C0000223

No, I didnt get back to the root of the page, but this is a GOOD example. The GM two-piece prop shaft is $1200 US. This one's $800-ish US. Give it a look.

Thanks for the link to diffs. Gonna go check it out now, then post up my findings right here.

couldnt get the email request to work, but I am moderately interested. Thanks for the link.

I'll pass on the CF prop shaft.

Like I said, I didnt bother following links back to the home page, but that was just an example. Lemme find the homepage of the driveshafts for ya.

EDIT: your truck wasnt supported by this site. They only had Trailblazer SS for 06-08. If it's the same specs, you should be able to make it work.