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Another Heating Issue (Flushed!)


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The other day when driving back from work I noticed the heat hand in my Brat was sitting at the bottom for a very long period of time. Right when I pulled into the apartment I looked down and seen the heat hand just a little bit below red and had zero heat coming out of vents. I drove it up the road today and it took longer to get warmer but I had intermittent heat. My radiator is constantly dripping out coolant and am sick and tired of smelling it and seeing it on the ground. Coolant is topped off, am I filling my radiator the wrong way? I just simply pour coolant in till it can't hold anymore. Overflow bottle is about to go on just to catch all the stupid coolant I am loosing.

 

I am leaning towards a heater core issue because I felt the two pipes today and one was hot while the other was warm. Next good day I get, I am flushing the SOB. Anybody else experienced this?

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first off let me suggest getting a overflow bottle in there, with long enough hose to reach it. (i used like a 32 oz gatorade bottle that is clear, and drilled a hole in the cap for the hose to go into) Remember to place the hose low enough, i placed mine over by the Jack on the left front, behind the AC compressor.

 

Also, I don't think the EA81 radiators are supposed to be filled to overflow. they are supposed to be filled to like approx 3/4 inch down from that. anybody else chime in here to clarify this.

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It sounds like a heater core to me. I think you know, but I wasn't sure when you said you filled it till it was full. But the way I always do it is, fill the radiator up with the car off, burp all the coolant lines you can get your hands on, and keep adding fluid as it goes down. Then, once you've got it good, fire it up with the rad cap off and add fluid as necessary, and watch the air bleed out. It really helps in these cars if you park uphill, or jack the front end up in the air. Run the car with the cap off till the tstat opens, and keep adding fluid as you need to. Then once its running, and there is no more air, or just small bubbles every now and then coming up, put the cap on and you should be ready to roll. I know you're no stranger though to subaru's, so if I just misunderstood and posted this all for nothing, I'm sorry :)

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Loyale you pretty much hit it right on the head, in this case, any input is good input.

 

I though about putting a little catch jug in where the black vacuum thing is but am unaware if I need it or not with the weber on there. There is two disconnected metal hoses with one running through the firewall. Bratman thinks it has to do with the fuel system and I thought it might have something to do with the vacuum assist brakes. If it doesn't, it would make a good place to put a tub.

 

Kyle

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Test/replace the radiator cap. It shouldn't be overflowing like that.

 

I doubt this is a heater core issue - when the coolant is low on an EA81 there won't be any flow through the core. If you have so little coolant that it's overheating then there's not going to be any flow through the core at all.

 

You need to find all your cooling system leaks. If it were me I would be pulling the intake manifold, addressing both the gaskets, the heater core bypass tube, heater core return line, both heater core hoses, the small hose to the carb base and the return to the block, all the steel nipples, and upper and lower radiator hoses. Do it all at once and replace the radiator cap and thermostat with new OEM parts. Same goes for the thermostat housing gasket and the intake manifold gaskets (careful with the bolts - 12 fl/lbs after chasing threads and use anti-sieze). THEN and only then can you rule out stuff other than the heater core, heat control valve, and radiator itself.

 

EA81's dont generally require much, if any "burping". Their cooling systems are well designed, and filling them when you first start the engine, and then once again after a cooldown is almost always sufficient.

 

GD

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GD, if you remember, I just recently replaced the intake gaskets back in October and you haggled with me about the price of gaskets from the dealer. Heater hoses have been replaced, thermostat and gasket has been replaced with OEM. I replaced the stant radiator cap with one off my hatchback that had no issues. Do you know where I can a pic of where at the base of the carb it would be leaking from?

 

When the issue decides to manifest itself, the heat hand will sit at half way and I will have ZERO heat.

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Have you tried flushing the core? Both ways? The line from the top of the water pump is the "in" and the other is the "out". Try flushing both ways.

 

Any indication of the heater control valve leaking under the dash? You say you can smell it.... those valves occasionally fail, and I've see leaks in heater core's where the coolant would run down under the carpet and out through the floor pan drain holes - leaving no indication on the carpet itself that you could see.

 

GD

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The carb base line is right in front - there's a tube that runs into the manifold right under the front of the carb base.

 

It's not just the hoses that can fail - without coolant being changed regularly corrosion will eat the hose barbs away and cause leaks too. You can just block the lines from the heater core bypass tube and the block that run to the carb base, and block the carb base tube as well.

 

A pressure tester to pressurize the cooling system while it's cold would help to find leaks, but the system on the EA81's is so simple you might as well spend the time just replacing all the stuff and have the peace of mind of knowing it's all new and R&R'd.

 

GD

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  • 2 weeks later...

I have been dealing with heating issues all week. Got to thinking about how the car will have a little heat and then a minute or so later will blow cool air, worse when in the "heat" position. Got to thinking that maybe the OEM thermostat is stuck half open and not letting enough coolant circulate back through the system. I ordered another one today and should be here Friday. Thinking will give heater core a good flushing next time I get a chance, with a good nozzle. Buddy has a laser temperature reader and will check things tomorrow when up to "normal" operating temperatures.

 

Opinions?

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I took some temperature readings with a laser tool today. All units are in the Fahrenheit scale. Taking after 15 minutes of idling with radiator cap off.

 

Outside Temp. 55°

Center of radiator-92°

Inside of radiator-99°

Bottom of radiator-140°

Lower Radiator house-136°

Water pump-170°

Upper radiator hose-135°

Thermostat housing where it meets intake manifold-170°

1 & 3 Cylinder head-220°

2 & 4 Cylinder head-193°

Heater hose to heater core-169°

Heater hose return-116°

Air temp coming out of vents-79°

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I have had the same problem with the heater blowing hot and cold on other cars, It was low coolant. The was caused by a leak in the system over time.

I recently replaced the hoses on my brat and by the alternator bracket is a "T" off that goes to the carb. There is a plastic valve in that line, that I broke and it leaked there. I removed the alt. mount so I could get to the hoses better, and replaced the valve with a junk yard special that I removed carefully. Hope this helps.

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I actually took some readings with my DMM's thermocouple today to double check the readings on the cluster of my Brat.

 

I monitored the temp over several cycles of the radiator fan both on the radiator and on the thermostat housing. The thermostat housing cycled between about 170 and 200. The radiator (top, middle) was a bit lower on both ends at around 150 to 190.

 

I think it's a mistake to run it as you were without the cap in place - that will not allow the system to pressurize properly and as a result your coolant would be approaching boiling point at very near the temp you measured at the 1/3 cylinder head. Boiling point of 50/50 is 223 degrees... with the cap in place it would be about 40 degrees higher than that. Assuming the system can build pressure properly - if you have leaks that may prevent the system from pressurizing.

 

GD

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Have you checked for debris blocking the airflow throught the core? Or is there sufficient air flow coming from the vents?

If you have hot hoses goint to and from the core and no heat from the vents, it could also be the flapper that directs the air flow. The one that moves when you turn the heat temp dial. Check under the dash for broken vacuum lines or one of the valves sticking.

But if you have an external, obvious leak, fix it first. If it's internal it's going to be a head gasket, manifold gasket, or the carb base gasket.

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The only leak that I get is from the overflow line off the side of the radiator. I checked for oil coolant and am not burning coolant either as motor still runs strong. Frank that sounds like a good idea as sometimes I have heat coming out of vents but when put in the "heat" position it blows cool air. Hopefully this weekend, cooling system will be douched and things will show some different results. What does this valve look like?

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Next time, after the car is warmed to where you have sufficient heat at both heater hoses under the hood, turn the fan(heater) on then watch the air temp coming from the vents. Probably just by holding your hand in front of it. If it's hot at first then cools right down, it may be as simple as a partially clogged heater core. The coolant flows through the core very slowly. Enough to heat it up, but not enough to replenish the heat lost that the fan is removing from it. Try flushing the core again through both hoses to back flush it. Or just flip-flop or switch hoses so the coolant flows through it in the reverse direction. It may push the gunk out after a few days, or a few minutes. But then you'll have to flush the entire system to get it out.

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The coolant flows through the core very slowly. Enough to heat it up, but not enough to replenish the heat lost that the fan is removing from it. Try flushing the core again through both hoses to back flush it.

 

Just went to town and back, this is exactly what it is doing. When flushing the core this weekend, do I need to use some kind of chemical solution or will just a pressure nozzle on a garden hose be sufficient?

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Go to the hardware store and buy a garden hose replacement fitting, like this one, A garden hose and heater hose are the same size, 5/8".

4143674947

 

Remove the heater hoses from the manifold but leave them connected to the core. Put this fitting in one and connect your garden hose. Start with very little pressure then slowly turn it up. I like to turn on the hose, kink it in my hand to stop the flow, connect it, then control the flow myself by releasing the kink slowly. Just remember that your home water pressure is 4 or 5 times greater than the pressure created in your cooling system, so go easy. After a few minutes, switch hoses and back flush. You may get a surge of brown funky water coming out as soon as you start the flow. Once the water flows through clear at a high rate in both directions, your done.

Some people have had heater cores blow out doing this, but the core was in bad shape to begin with.

If this doesn't work by getting the build up out, you can drain the coolant from the system, add a good flushing agent, reverse the hoses to reverse flow through the core and go for a drive, or you may have to change the core.

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Flushed her today.

 

I found the garden hose fitting at the Lowe's last night, and what a tool! Fits perfectly inside the heater hoses and holds itself so you can run and turn water off. I started with flushing the hoses, then stuck it in the radiator and alternated between putting my finger off the tubes that come off the intake manifold that the heater hoses clamp to. Seen a good couple wads of trash come shooting out of the tubes. Then replaced another OEM thermostat with another OEM.

 

Filled it back up with water drove it up the road and back. Had great heat the entire time and was even running a little cooler. Drove it back home and repeated processes. Drained radiator and put new anti-freeze back in. I attempted the "fill on an incline" process to try and eliminate air in my system. We will have to wait and see how that turns out. Drove the twenty minutes back to my apartment and had heat the entire time at an average speed of 60 mph.

 

I am hoping I fixed this issue once and for all. Thanks to everyone that contributed to helping me keep my Brat on the road.

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