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Help! Can't get air bubble out of the Blazer's cooling system!!


Nitrousbird

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I noticed my 93 S-Blazer was leaking coolant. Looked like it was coming from the water pump, and since the pump is only $14, I replaced it. Well, I noticed the fan clutch had some forward/backwards play, so I replaced that too (which was $65). Well, the truck runs smoother, but the next day, I notice it is still leaking.

 

Upon further investigation, looks like the leak was from the upper heater hose (previous owner put this cheapo hose on there). When I pulled the old hose, a ton of coolant came out of the intake manifold. Put the new hose on, fill the radiator, but I put far less coolant in that came out.

 

I start the truck, yet it still won't take more coolant. I top it off, fill the reserve tank. Every time I drive it on the highway, it warms up to around 240 degrees....the truck has a 180 T-stat in it, and usually sits at about 185 (this is me trying to go by my dinky cheap aftermarket temp gauge). When idling, it cools down to around 220 or so.

 

I've heat cycled it several times (from dead cold to almost overheating). I've tried topping off the coolant system, but it just won't take any more coolant. All of the hoses get warm, and when I push on any of them, it makes the coolant rise in the radiator slightly.

 

The hoses for the cooling system are as follows:

- Hose from the top of the radiator to the overflow tank

- Hose from the lower passenger side radiator to the water pump

- Hose from the T-stat housing to the upper radiator (opposite side to the lower radiator hose)

- Hose from intake to one side of the heater core.

- Other heater core outlet to the middle pass side of the radiator.

 

Any ideas?? I really need to get this fixed; I can't keep driving it like this.

 

Edit: I flushed the cooling system very well this past summer. The radiator is a little over 2 years old, and everything seems pretty clean in the system, so I doubt unlodged deposits are the cause of this.

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Go to Pepboys and purchase a "Spill-Free Funnel". It's a funnel that has a radiator cap adapter. You sit that on top of the radiator filler kneck with coolant in it, and let the truck idle for a while. Any air in the system will bleed out through the funnel and then instantly be replaced with coolant. Make sure you have your heater on full blast. That should take care of the problem.
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Guest nevarmore

If I had to take a stab at this I'd get a funnel and a smallish piece of tubing, 1/2" at best. Assembele these into something looking like a beer bong. Take off any hoses carrying coolant that you can get to, slide the hose as far in as you can get it, then start pouring in your 50/50 coolant mix. Beware, this is a wild ass guess (WAG) its not easy and may be harmful, proceed at your own risk.

 

Have you tried running the heater? There may be some pressure or air pockets tha would move along if the heater core has some fluids pumping through it.

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You can also try parking it on an incline, or raisingt he front end at a good angle. The running the vehicle with the heater on. The air will travel to the highest point, which should be the radiator cap.

 

Leave the cap off obviously, and add coolant as you can.

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does the upper radiator hose pressurize? if not the thermostat is stuck shut you need to fill the coolin system with the engine ideling and the radiator cap off. if your going to be working on it soon pm and I'll give you a hand with it scince I just live down the street.
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This took an interesting turn.

 

On Saturday, Trevor and I pulled the thermostat, boiled it, and it was working fine. Toss it all back together, and I was able to get more coolant in than ever before.

 

SOOOOO, put it all back together, and the temp gauge slowly climbs like normal, but climbs up to around 240 degrees. WTF. The engine didn't seem hot, radiator wasn't overly hot, all of the hoses were warm. My truck a while ago had a cooling problem, and had gotten up to temps like that before, and back then, when it got that hot, you could VERY easily tell it was that hot under the hood.

 

I have an OBD-I cable for my laptop, plus software for my Formula to do programming as well as data logging. Well, I also have software that will Datalog for my Blazer (got it free :D ). Log my drive to work, and the temp gauge is going up the same as what the PCM reads (PCM uses a different coolant sensor). After the PCM hits around 177, it leveled off and stayed there, but the gauge shot right up to 240 and stayed there.

 

Looks like my aftermarket gauge is bad. Time for another one or to fix the stocker.

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Well I'm probably the radiator expert. I have 20 feet of radiator lines and 5 gallons of fluid in my system. turn the heater on and point the front of the vehicle at a very high angle (ie road bank on highway near stream or something)

 

thats a good way to do it in the future. Also you should push on the radiator hoses to see if you can feel water flowing onces its reached normal operating temp.

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