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Poor heat in '85 Buick


Guest imported_TheColossusofRoads

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Guest imported_TheColossusofRoads

Over the past few winters the heat output in my '85 LeSabre has gradually become cooler and cooler. The heater core, 195 degree thermostat, and radiator have been replaced during this time period, (routine repairs), and the only difference was the radiator was replaced by a heavier-duty unit. It is now at the point where it just barely keeps me warm enough when the outside temperature gets near single digits, and even then it takes a long time to reach that temperature. Can anyone think of anything else to try?

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A couple of other things to check would be if the heater door is moving full travel to close off cool air from getting in around it. Another thing is that new thermostats may not be as high quality as the original, try a Stant or original GM to see if that is the problem as well. A heavy duty radiator is designed to keep the engine cool in summer, however it doesn't know that the seasons have changed and wil try to do the same in winter! Make sure that you have good coolant flow to, thru and from the heater core. Good luck with your heat problem, I'm from Minnesota and it is 3 degrees F. as I type this! Tim McCluskey <img src="http://www.aaca.org/ubbthreads/images/graemlins/wink.gif" alt="" />

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If the radiator is too big, and is cooling the antifreeze at a faster rate than the original radiator, I would imagine that the thermostat would stay closed or at least not fully open so that a constant temperature is maintained in the block. So I don't think the larger radiator has any effect on the amount of heat in the car. I do however think the thermostat needs to be replaced with a better quality one - how about a clogged heater core - that would result in poor cabin heat as well. My dad has a '95 Ford and his temp gage as well as well as his heat didn't work and a new thermostat fixed both. Think warm!

Cheers!

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Guest Skyking

The same problem is happening with my 87 ElCamino. I replaced the radiator last summer with a larger one and the temp gauge doesn't move off cold. I freeze every time I drive it, and right now our temperture has been in the single digits. I think changing the thermostat is the first order. This was a Florida car, maybe it's getting back at me. <img src="http://www.aaca.org/ubbthreads/images/graemlins/shocked.gif" alt="" /> <img src="http://www.aaca.org/ubbthreads/images/graemlins/confused.gif" alt="" />

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I believe almost all cars at least from 1970 have a vacuum actuated in-line valve in the incoming heater hose line to the heater core that shuts and opens depending on setting of heat or AC. After all you do not want 190 degree water circulating in the heater core in the summer when want good air conditioning.

They do fail and won't open when supposed to (or sometimes lack of vacuum keeps that valve from working -- a leak).

If have changed out the thermostat and heater core and radiator, I think you should check that valve out for malfunction. I don't think a larger radiator would make any difference if thermostat is good.

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Skyking That reminds me:

Of a 1963 Ford Galaxie I once owned when it was 3 years old. Was serviced in Illinois one summer before return to Florida and the mechanic in Illinois told me he put a "Florida thermostat" in it.

Next winter the heater would not work worth a crap. Pulled the thermostat and found it was stuck permanently wide open. I guess that was his idea of a "Florida thermostat" Can't believe I had actually paid the guy for that. Guess he got a good laugh out of it anyway.

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I had that problem in my 71 Riv and I fixed it really easy. When the engine is cold pull the hoses on the heater core. Then hold a garden hose up to one end and let it wash all the crap out of the core, it worked like a charm.

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That's a good idea. I think it is supposed to be best to run the flow backwards with that garden hose. (at least at first, so you don't cram a whole bunch of junk in tighter in that heater core).

Wouldn't think he'd have much crap in there though if heater core and radiator fairly new. But it is worth a try and easy to do.

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Easiest way to tell inlet from outlet on a heater core is to look for that vacuum actuated shut off valve I was talking about before. It will be on the inlet.

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Guest imported_TheColossusofRoads

The heater core is brand new, the radiator was replaced not too long ago (with a larger one) and the thermostat was done within the last month. The cooling system shows absolutely no signs of corrosion or crud anywhere, in fact the old heater core was clean as a whistle, except for a pinhole leak. I'll try checking for an inlet vacuum valve problem - after that I guess it's cardboard time. I wish this car had gauges - all my others do.

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Speaking of gages, have you thought of purchasing an infrared temp gage? We got one from J.C. Whitney for about $75. I didn't trust the temp gage on our Super so I got this infrared gage and it helps set my mind at ease when I think the car is running hot. It might be a worthwhile investment or maybe you can drive the car for a while and stop by a service station and ask to borrow their gage (if they have one).

Cheers!

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I'm not sure of how the instrument works internally, but it basically looks like a handgun/kinda-sorta, and you point it at an object and it will read the temperature of that object. It has a digital display, easy to read and operate.

This is starting to sound more like a commercial ... how much would you pay for an infrared thermometer? Don't answer just yet because if you act now, we'll throw in a new thermostat! That's right you get both pieces for just three low monthly payments of just $199.99 ....... <img src="http://www.aaca.org/ubbthreads/images/graemlins/grin.gif" alt="" />

Cheers!

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It might be that you are over cooling the water with the larger rad. the school buses with large rads and such have a problem the the water in the rads is ice cold when the motor warms up, the thermostat opens up in the top of the motor, and floods the motor with the ice cold water from the bottom to the top then shuts off the water flow, never really producing any real heat in the heater core before it's flooded with the cold water again. Check to see if the rad hoses build any sort of pressure, the rad should be around 100degF min.

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<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">Infrared temp gauge? Never heard of that. How does it work exactly? </div></div>

My dad bought one of those to check heat on his Studebaker because it is always running hot. Its pretty neat, you shoot the theromstat housing and it reads 190, you shoot the exhaust manifold and it reads 350. You can even shoot the top and bottom radiator hoses to check its efficiency. Its really interesting. I shot the sheetmetal on a white car and a brown car and found a 35 deg difference between the surface temps.

<img src="http://www.aaca.org/ubbthreads/images/graemlins/smile.gif" alt="" /> The other day my dad was feeling sick, so he has me shoot him in the tongue <img src="http://www.aaca.org/ubbthreads/images/graemlins/grin.gif" alt="" /> <img src="http://www.aaca.org/ubbthreads/images/graemlins/grin.gif" alt="" /> It read 96 deg so I guess he didn't have a fever.

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