Im getting an 04 blazer with 60k miles on it(non rebuilt) and it still has the original dexcool fluid in it, the heater core is gunked up too. I know this fluid makes the lower gaskets go bad, no signs of leaks, but I am wondering if I should just go ahead and change them anyway, or just do a coolant flush?

 

Dexcool needs to be flushed every 3 years or 36K miles or you will have problems. If you don't know the history, you're better off flushing it ASAP. Flush each component separately, in both directions, (radiator, heater core, engine block, and reservoir). Refill with Dexcool, replace the radiator cap, & thermostat.


Intake gaskets are made by Felpro # MS98002T. Not a difficult job, but it is time consuming, and it has certain things that MUST be done correctly, or you will have problems. You will need an accurate inch pound, and foot pound torque wrench, 5/16 x 18 tap & die, and some basic hand tools.

 

Sounds like a nice one!! 60K!! Has it been kept out of the salt as well?

Only down-side I have heard for Dexcool is you can't run it low (with air in the system) and I have also heard that it wasn't quite compatible with the original plastic LIM gaskets (hence the failures in Vortec V6 and V8 engines).

Since the vehicle is new to you and you don't know what intake gaskets are in there, probably best to change them out with the Felpros if you plan on keeping the vehicle. Leaky intake manifolds take out crank bearings when they leak coolant into the engine. I believe this was the original problem with my 2001 creampuff with only 65K miles. Go back with Dex-cool, keep it full, and change it very few years. Your cooling system will appreciate it. Green antifreeze is substandard for use in your Blazer.

Just use the Felpro gaskets Captain listed exactly per Felpro instructions and be sure to get all the gunk out of the intake bolt holes in the heads with a tap and wire brush the bolt threads clean. Use liquid white pipe sealer and tighten in sequence to specs with an INCH-POUND torque wrench. Let sit overnight and go over them a second time in sequence before buttoning them up. Do not over-tighten and do not under-tighten any bolt This is critical.

Don't forget distributor and injection spider inspection/maintenance while it is out. Another problem area for the Blazers.

Good luck and best wishes

 

Yes I know about it, I've done it before (same reason of gunking stuff up and destroying gaskets) so I know how to do it. Just looking for if I should just flush it out or go ahead and just redo the gaskets and clean it out. I'll probably just do the gaskets when I get the time for it.

 

They should both be done, along with an oil change. It would be best to flush it first, and inspect the passages after the intake is off. If it still looks nasty inside, flush it again after the intakes are done. Then do the oil & filter. There are about a hundred posts about Dexcool on the forum, so I won't get into it here, but, there are several reasons to use Dexcool. The two main reasons are that Ethylene glycol, (green) has silicate, (sand) which will destroy the water pump seal prematurely. And, ethylene glycol does not protect aluminum, (Heater core, radiator, intake manifold, etc). Your choice