97 Blazer, mystery coolant leak.

1997 Chevy Blazer S-10, 65,000 miles.

Noticed it engine over heat, went to Jiffy Lube:
Radiator cap replacement (not keeping pressure),
topped off dexcool (they tell me it was low)

worked fine for about a month, then severe overheating, went to Tunex:
replacement of thermostat,
coolant flush and replacement with classic green coolant,
(they tell me i had very low coolant in the system)

worked fine for about 2 weeks, then starts to over heat again, went back to Tunex:
found coolant low, added coolant (they tell me it might have been an air bubble in the system)

worked fine for 1 week. now overheating again. :(

discoveries:
from cold start, engine would heat up pretty quickly, if I engage the heater, cold air comes out of the vent.
if I continue to drive in this condition, it would continue to overheat until I hear this clicking sound from behind the dash, the temperature would drop and the vent blows warm air for like 20 seconds. Temperature would build backup and vent goes cold until next clicking noise.

I am now feeding it half a gallon of coolant a day. it always seems to be thirsty, what could be wrong with it?

Thanks,
Rob

check the water pump.......!!!!!

The anti-freeze has to be going somewhere. Do you have excessive white exhaust smoke? If you do, most likely you have a bad head gasket.
(Compression check of all cylinders will verify this)

Check your oil to to see if anti-freeze is leaking into it. (This would indicate either a bad intake manifold gasket, or bad head gasket).

If oil is O.K., check the overflow tank. Is it full ? If so, you have a bad thermostat. Your symptoms indicate a bad Thermostat.

Losing that much coolant, you should see it on the street/garage floor easily. If no leak apparent and with the overheating, I'm guessing a head gasket. If it were the normal intake gasket failure that is so common these days, you'd notice some serious engine noise on startup from the oil breaking down, and you'd see some really bad looking oil on the dipstick. So I'm guessing head gasket.

Engine warming up very quickly is a characteristic of there being air in the coolant system. The coolant has to be going somewhere, and if you're not seeing it on the ground, it's definately head/intake gasket failure.

Keep on adding coolant to the rad when the engine is cold and has been sitting overnight.

If you go out in the morning and open the rad and you see that it is not up to the top, your rad cap is not sealing properly and you will need another one rated for 15 or 16psi.

I would check and see if the rad cap they put on is the proper one.

Do this every morning for a couple of days to force the air out of the system.

[
hey i have a97 blazer with the same problem except i finally started to see leaking anti freeze top of motor intake manifold bolts lose these blazers are know to have bad gaskets ifound 1/4 leak on edge of manifold under air condition compressor cleaned spot mixed up 2 part epoxy filled gap or have new gasket put in 500.00 dollars my fix worked great runs 1005 better and no more random check engine light

Isn't that the thermostat housing?

following the advise of the board, I checked the oil and found that it indeed have coolant in it. I took it to the dealer and they placed the intake manifold. $616 dollars later, it seems to work fine.

They did tell me that since coolant is bad for the engine, and that I may experience future enginer failure. Should I assume the truck will last me one year at least until I can get a new one?

Thanks for the advise everyone.

following the advise of the board, I checked the oil and found that it indeed have coolant in it. I took it to the dealer and they placed the intake manifold. $616 dollars later, it seems to work fine.

They did tell me that since coolant is bad for the engine, and that I may experience future enginer failure. Should I assume the truck will last me one year at least until I can get a new one?

Thanks for the advise everyone.

I had the same thing happen with an '93 S10. After replacing the intake manifold gasket, I drove it for another 6 months without any problems,Then traded it for the biggest POS I ever bought, '97 Blazer-Ha.

You are probably O.K. for now, unless you drove to the point of overheating the engine excessively (That's how I found my problem, engine overheated).
Good Luck

following the advise of the board, I checked the oil and found that it indeed have coolant in it. I took it to the dealer and they placed the intake manifold. $616 dollars later, it seems to work fine.

They did tell me that since coolant is bad for the engine, and that I may experience future enginer failure. Should I assume the truck will last me one year at least until I can get a new one?

Thanks for the advise everyone.

How long was it like this?