Alright, I think I dun messed up big time with my 04 Blazer 2wd. Lets go ahead and get some opinions from you guys. Here's what's going on -

I got my Blazer back in 08 or 09 and when I got it, it was in just great condition. It still is for the most part, because I try to fix things that I know how or can figure out. Well, call it lack of attention to detail or not seeing things or whatever you want to call it, but for the longest time, I just did not see the radiator cap on my Blazer. I did think it was odd that I could only check things via my reservoir, but I was more focused on other parts of the engine and didn't pay much attention to my radiator. Then, once I did finally find it I couldn't get that sucker turned off of the radiator to save my life. Just a horrible design for a radiator cap in my opinion. So I just never pulled it off and kept an eye on the fluid color/level in my reservoir. Here's where the problems start.

Last Summer (13) a local shop is doing a repair to my Blazer and they go ahead and check it over for other issues. One of their checks is that they check the radiator by pulling the cap. Well, this turned out that I had a huge problem. The fluid at the top of the radiator was so bad that it was like a mixture of sludge and some sand in there as well. I've never seen anything like it! So I get it to a radiator specialty shop in town and I tell them I'm going to need a new radiator as well as a complete cooling system flush and put the green stuff in because I'm more used to working with it and trust it more. The guys tell me no problem, and they did what I asked. About a week after I picked it up, I'm checking the fluid level in my radiator and reservoir (new radiator has the style cap I like) and I notice that it's turned brown! I asked the shop about this and they told me that since I had them put green in it, they don't back it up with any warranty, but the color was probably ok.

After about a year of that and I just don't like how that looks nor do I trust anyone to do the job right or at a price I can afford, I decided to do the flush myself. I made sure to run my heater while doing the flush so I could make sure my heater core got flushed out, and I used the stuff you get at the store to clean out your cooling system. I really paid attention to what I was doing and made sure the water coming out was just crystal clear before I put anything back in it. Sure enough, a month later, I'm back to having brown fluid and it's been that way ever since (I plan on doing another flush in a month or so and keep doing them until I can fix this issue with color).

Well, this past weekend my heater core blew out. So I started doing a little research on here and find out about my horrible mistake of having green put in there and I read about how green can lead to premature failure of the heater core, and how the little chunks of rust can lead to premature failure of my water pump.

So, how screwed am I guys? Do I just need to stock up on heater cores, radiators, and water pumps, or is there a way to save the system? Other than a weird engine vibration that everyone can see but nobody can figure out, this is my only issue I have with the truck. I've got a pretty good tool set, Haynes Manual, and I don't mind tearing stuff apart if it's going to get the job done right. I just need some direction before I make any more bad decisions with this.

 

My $0.02 worth: replace the heater core and continue on. The problem as you have found is the mixing of green and orange coolant....turns to sludge. The cooling system flushing you are doing does not get 100% so some orange / green coolant remains in the bottom corners of the block.

Only real way to get 100% is to remove engine, tear-down, hot tank block. However probably 98% can be obtained by removing freeze plug on both sides of block and using spray nozzles and a lot of water into these holes, you will get 98% of the coolant out.

Super messy job, coolant/water everywhere!!! Not a job that I would want to do.

The heater core has the smallest passages and clogged-up first. So replace it and continue on. Over time it may have to be replaced again, and/or the radiator; water pump....probably just once...but at least it is easy to replace unlike the heater core!

Again just my $0.02 worth.....good luck.

 

Yea, I've always heard that the dash is a pain to take apart to get to that heater core, but I never understood just how bad it really is until I went to Youtube last night! lol I've completely torn down Detroit DD15 engines, a few Cat C12's, and a Mercedes truck engine, but that dash is looking like it's still going to be quite a job.

 

I have three GM vehicles that are involved with the dex Cool problem. My 'new' 2003 Chev Blazer, my 96 Chev Lumina, and my Chev Impala SS. A 4WD, a FWD, and a RWD. GM introduced Dex Cool as a five year 'long life' coolant. I converted the 94 Impala which came from the factory with the green to Dex Cool per the Impala Forum recommendation. Bad choice! There are two main theories on why the Dex Cool turns to a brown rusty mud in the cooling system: One is it happens when it is mixed with the Green coolant and another is it shouldn't be run for 5 years-- it is good, but only for 2 years or less. Think about that last theory! If it is only good for only one or two years, It shouldn't have been promoted as a long life aka 5 year product. But GM has not stood behind their mistake. My latest bad experience with Dex Cool is in my 96 Lumina with a 3.1L V6 engine. I lent this car to my dau. and the engine burned up in August. Diagnosis: The radiator clogged up with brown, rusty sediment. I asked the dealer to hold the radiator for me, but they threw it away. I wanted to present it to GM.

 

mech cb: actually dash removal is not all that bad...really. Have to remove the center console and then all the lower trim panels and disconnect the parking brake cable, drop the steering column down (be sure to support it), 4x4 switch if equipped, dash trim panel, speedo/tack cluster, dash speakers and defroster grill for screw access, remove the top screws and there are three/four 10mm head bolts to come out and then the entire dash will lift out through the passenger side.

Now you can access the heater core....which I have not done on my '02 (yet...knock on wood).

Take some pictures and post them here....I think many would like to see a dash removal.

Have fun.

 

That's a great idea, actually! I'm gonna have to do it anyways simply because I can't afford shop labor and winter is a comin....I'm just waiting until the first when I can afford one. So hopefully we'll have photos around the first. Thankyou for the words of encouragement!

 

You need to look at the Tech Articles section of this forum. There is a lot of discussion and lesson learned from other forums members who have tackled the heater core replacement.

 

RE: the heater core is blown out. Do you know you can drive it ( until the cold weather hits) by eliminating the Heater Core from the system. Remove the two hoses at the water pump and loop them back with a section of hose. If the outlet and inlets are diff. sizes, you will have to put a 'splice' in the loop and use two diff. sizes of hose. This is just to allow you to drive the vehicle in the warm weather while you are getting ready to permanently fix the core.
For those of you who have a Dex Cool sludged system, but the heather core is still intact: try this method to flush out the core. Remove those two hoses and using water pressure only, flush one hose , then the other side to remove the sludge in the Htr core. Caution: Do not use a high pressure sprayer hose or you will blow out the core! USE standard water pressure only. Be sure the heater valve is OPEN to allow the water to flow. If the heater valve won't open, try this reverse flush beyond the valve, closer to the core. Keep flushing it until the water runs clear.

 

I didn't know this was covered in the Tech Articles. I'll have to go do some research on that. Thanks for the heads up!

I was originally stranded about 45 miles from home when my heater core blew out on me friday night. So I got a tow to Walmart around midnight, camped out in the truck, and then the next morning when the engine had cooled off, I went inside and bought some cheap tools so I could bypass the heater core, remove the thermostat (it had seized up), and refilled the engine with DexCool. When I removed the thermostat, I couldn't see any coolant in the block. Luckily, there doesn't seem to have been any damage caused by it. After all that and jumping a dead battery (it died while waiting for a tow), I was finally able to get home saturday around 11. Loooooong night!

 

For the heater core: Have a look at this:

https://blazerforum.com/forum/articl...removal-82805/

It actually works without removing the dash at all. If you have a good tooling you should be able to assemble a long enough ratchet arm.

For the cooling flush: I'm running green anti-freeze for 20 years on a 1994 S10 4.3L V6. Color changes over time as well but it takes mor than 4 years to turn from the green to brown. As for flushing the cooling system having the heater core out may turn out to be a lucky strike. The heater core is fed by the line leaving the heads on the rear top of the block on some S10. Use that for an outlet on the block side of flushing.

When flushing from the radiator side into the block the only issue you have with having water circulate all the way is the thermostat. Just remove it and put the casing back on. I was then able to flush the radiator and the block in the car with a machined (turning lathe) part to attach to the radiator hoses respectively to the radiator itself. While the next time I'll remove the radiator.

Not sure about the 2nd gen - you may need to do some more research.

Good luck