Cooling system trouble.

[Lyle's GTP]

Car's losing coolant some where "very slowly, a jug a year maybe", not leaking as far as I can tell. Changed water pump, rad cap, lower heater hose (you know the one), and the air bleeder valve (over tightened the screw ).

Anyway, it shows a low coolant light most of the time but the rad is full and coolant tank is full. But yesterday I bleed the air from the system and very little came out, and the rad is low but the coolant tank is full????

I think maybe my rad is pooched, any suggestions? By the way I don't think the car is burning it. No evidence of leaky intake manifold gaskets either.

Help, Pleeeeeeeeeease. I hate garages but I think it's my only option. I don't have a pressure tester.

Lyle

[4spdz34]

there is a sensor on the passenger side of your radiator about half-way down, it will just pop out, clean it off, thats why your light is on more than likely. and check the coolant pipes by the throttle body the leak and go right on the crossover so u will never see a leak.

[Lyle's GTP]

I'll check the sensor, but why wouldn't it pull from the tank?

Lyle

[bud36light]

What do ya mean pop it from the tank?

[4spdz34]

it will come right out it has like to clips(bad explanation) on the sides of it that hold it to the plastic part of the tank.

[Lyle's GTP]

What are you talking about? I meant, why doesn't the coolant flow from the coolant over-flow tank into the radiator, when the radiator starts to get low? Shouldn't it?....Isn't that it's purpose?

Lyle

[4spdz34]

o sorry i misunderstood. it is supposed to flow, but only when the system is under pressure. and there might be a blockage in the line from the overflow tank

[pontiac92gp]

Had same problem .. radiator caps get old. Replace cap and should allow flow.

[Lyle's GTP]

Did replace it, this is the new one. I will shoot someone if this doesn't work too. But what if the system has such a large leak (not a flowing leak) that the system can't create any pressure?

Lyle

[pocket-rocket]

Sometimes the lower intake gaskets leak coolant too. Thats where mine are leaking in the 91 right now, but since I keep an eye on the level, and know where the leak is, it doesn't bother me.

[Lyle's GTP]

Alright, I know this is old but I'm finishing this one off. I'm board at work and maybe it will help someone in the future.

OK, I beleive I've solved the problem with this cooling system shit. My problems didn't change. The coolant wasn't getting pulled into the rad from the tank and was disappearing somewhere. Plus I had a constant low coolant dummy light. So, as instructed I cleaned it reinstalled it changed my coolant and filled it appropriately. The light went out immediatily, but the fucker came on a day later and then it was on and off day by day start to start, all over the place. Plus the coolant tank thing was still going on. So, I was at GM one day so, I picked up another new rad cap. Put it on, but I noticed these neat little arrows and a message that read, "Align With Tube". My no name rad cap never had this (fuckers). So, I'll be damned all the way to hell, it worked (I'm not sure how) but it worked. The coolant light went out a day later and hasn't been on since, it's been a month now. I haven't used a drop of coolant or sniffed that evil light. Whoo-Hoo!!!

Lyle

[Juglenaut]

What are you talking about? I meant, why doesn't the coolant flow from the coolant over-flow tank into the radiator, when the radiator starts to get low

If you are using a jug a year then I would wonder to.

Check all the heater lines all the way around sometimes they leak very slow but not to fast that it leaves evidence.

Pressure leaking out of the coolant system will hinder the capability to draw coolant from the over-flow, reason is that hot liquids expand and release into the tank if there is a good enough leak the back pressure in the radiator when it cools is not strong enough to pull the coolant back.

[Lyle's GTP]

Yeah, I think it was leaking from that dreaded 3/4" plenum line. But I recently changed the lower intake gaskets and that line, in search of this problem. I replaced the hose and got some real clamps. The dreaded bitch hose did show signs of leakage, nothing major though. Every other hose seems fine, so I am confident I have solved the problem.

Lyle

[pocket-rocket]

Check your coolant pipe for the heater core (the one that has the quick disconnect that goes into the lower intake under the TB). Those usually leak too, and since it dumps right on top of the exhaust cross over pipe, all evidence boils away.

[Lyle's GTP]

I had the lower intake off and there wasn't any quick disconnect on there. There was a 3/8" NPT fitting on the hose you speak of. The only other possiblities are the O-ring that fits between the upper intake and lower. Then thermostat and the lower intake gaskets themselves. But I put lots of sealant on the NPT fitting and tightened it down real good. Then I put in a new thermostat and O-ring. Then I changed the Lower intake gaskets with a fresh set of Felpro's. Plus, did I mentioned that I changed that 3/4" hose and put some real clamps on it. Oh, and I took out the Temp. sender and put some new sealant on that too, just to be sure. So, I don't think I will have any more problems, I don't think I missed anything.

Lyle