QS 5W30 2k Blazer 4.3L 5k OCI *Coolant leak*

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Aug 9, 2005
2000 Chevy Blazer 4.3L V6 79k vehicle miles 5k OCI on QS 5W30 dino questions: 1)will the GM cooling system tablets solve the coolant leak? 2)should I flush the coolant before adding the tablets? (I think it's due for a flush anyway) 3)how much to replace to IM gasket? 4)what about the fuel? injector stuck open? how do I figure out which one? Thanks for your comments! Code:
OCI	5k	Universal Avg.
Veh Mi	79k	
Type	QS 5W30	
Date	9/4/2006	
Al	4	3
Cr	1	1
Fe	31	15
Cu	3	5
Pb	8	8
Sn	2	1
Mo	77	62
Ni	1	0
Mn	1	1
Ag	0	0
Ti	0	0
K	190	7
B	18	38
Si	24	18
Na	13	10
Ca	1901	1890
Mg	9	163
P	572	735
Zn	734	888
Ba	0	0
Visc	57	53-65
Flsh Pt	270	>365
Fuel	4.8	<2.0
Coolant	POS	0
H2O	0	0
Insol	0.4	<0.6

The cooling system tabs won't solve the problem per say but it will mask it or essentially slow it down. Your leak looks fairly significant as many times, the analysis labs will not specifically state POS for coolent, yet there will be abnormal levels of Na and K. Your looking at about $700 to $800 to get the gaskets replaced. If it was my truck, I would go to Walmart, get a tube of Bars Golden seal powder cooling system sealer (identical to the GM tabs but in powder form and much cheaper), add at the radiator filler neck (not the overflow tank), mix around with a screwdriver (add small amounts at a time), take it for a 45 minute drive with the heater on full blast (so the sealer just doesn't back up at the heater core), do a 3,000 mile run with new oil and resample and see what happens. I've had great success with the Bars leak stopper in my Dad's 98 Blazer 4.3; it stopped a weapy heater core. If $800 won't break the bank, get the gaskets replaced though with the Felpro problem solver gasket kit. problem solved for good after that! Good luck - from a fellow GM gasket leaker owner
we had a member here that used the coolant tabs and his later UOA's..the coolant leak was almost nonexistent. I would flush the coolant. I've heard they are $700-800 to replace gasket. depends on the model. 4.8 is alot of fuel. did you get the sample real hot when you took it?
the oil was hot, but it wasn't driven on the hwy or anything. just city driving. looks like I'll be getting that Bars Golden powder.
I think the "POS", next to where it says coolant sums up my feeling about this series of GM motors. The increase in Fe wear is a direct result of the massive amount of fuel dilution. I'd say you have an injector that's leaking after shutdown into the sump. Note the very low FP of +270F - it's been a while since I've seen one that low. TS
TS - so you think the Fe is from the cylinder walls being washed by the gas? I thought it was from the coolant. I guess I have 2 problems to fix.
Change the intake gasket that will usually fix the coolant. On the fuel side I would look at the fuel pressure regualtor first and go from there. I recently fixed my 5.7 using the GM gaskets and upgrading the fuel injection system to MPI because I had 3 leaking poppets and the housing leaking next to the regulator due to a small crack. On the blazers though fuel problems are sadly the norm. I sold my 200 after fixing the intake. I only need one to worry about. Do not use that [censored] to fix a leaking gasket because it wont fix it.
Sky Jumper, As a 4.3L user myself, you are not seeing a huge leak in your UOA. Do not go and dump a whole load of the leak powder stuff into your cooling system. Get your coolant changed and then add the two GM sealing tabs to solve any potential leaks. It will solve them. I had a coolant leak bu it was from a leaking rad and a crack in the oil cooler allowing coolant into the oil. You have the defective AC Delco rad cap which doesn't seal, and exposes the dexcool to air which turns it acidic which then eats the rad and causes small pin holes to form. I have intimate knowledge of this seeing I found coolant in my PCV catchcan adn within 1 week my tranny went out. When they tore it apart, the coolant was in the tranny cooler as well which went and killed the tranny. Don't always go for the intake gaskets, the all in one rad with oil and tranny coolers let loose prematurely as well.
Why not use the powder seal, it's the exact same thing? And it doesn't have to dissolve like the pellet. Gm states to install the pellets at the lower rad hose so they don't just sit on the upper rad fins in a big glob. And it likely is the intake gasket leaking. The 4.3L is a notorious leaker like the others. There's only one way to find out though and that's to have it professionally diagnosed.
SJ, The bigger problem here is all that fuel.... If this was fuel wash during operation, I think you'd see more chrome and aluminum from piston ring/skirt wear. In this case the fuel is degrading the integrity of the AW additives in the valvetrain, hence the higher iron. TS
Sealing tabs aren't a good band aid period. The vehicle is the right age and mileage for the gaskets to give out. I been there done that on several occasions and the gaskets were the cause every time. And since that only prolongs the antifreeze in the oil it will further erode the bearings. Not to mention the internal fuel leak. Fix it right the first time and be done with it.
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