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#1
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thermostat???
ok...i just put in a new heater core in my 75 duster, and im getting no heat when the car is at running temp...yet i have no leaks.. on top of that i dont think my thermostat is working right its a 180 degree and its spiking to 210 and not functioning right in the middle of winter!.. now does the thermostat control flow to the heater core as well as the rad??? can someone help me out??
thanks |
#2
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Hoses
Are the heater hoses connected to the correct places on the core? Disconnect one, and start the engine. Should have pressure. Disconnect the other, should have suction. Now check the core for indication of inlet side and outlet side. Hook them up accordingly, pressure to inlet.
My small block has different sized hoses for inlet/outlet. Do big blocks also? |
#3
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Quote:
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#4
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You could have crap blocking the passage in the block. Disconnect one hose, start the engine and make sure that you are getting flow. If you aren't, then there is a restriction in the block. It's also possible that you could have had crap in the passages and it ended up in the core and plugged it.
I would look at getting a new thermostat. Get one of the Mr. Gasket Hi-Flow designs. They work great. |
#5
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Quote:
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#6
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are you sure that the air doors are opening? That the blower fan is operating? Just some ideas...
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#7
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i know their working....i checked those first then put my hand in there to feel the core and it was cold... thanks though
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#8
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Do you have that, ummm, thing, do hickey, (DAMN IT!) valve on the heater hose?
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#9
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heater control valve. Some are vacuum contolled, some are cable. Easy to test either way. I forgot about that.Duh ha ha
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#10
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Yeaaa, thats the thingy, do-hickey etc.......
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#11
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no not that i know of...the hoses run straight from the block/pump to the core...
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#12
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are you sure that the waterpump is circulating the coolant? Also as far as the high temp prob, be sure youre using a rad cap that is the right pressure and is actually up to psi spec. Just more things to check...
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#13
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i thought a rad cap regulated when to let fluid into the over flow??? and i know i am having problems with the thermostat... but i wasnt shure if that affected the heater core at all
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#14
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I'd say that may have something to do with the high engine temps. Had the same problem. I changed the cap & added an overflow. No more heating issues & no more coolant on the driveway after shutoff. If you think the cap is suspect, it doesnt get any cheaper or easier to correct. Also, what size rad are you using? With the BB I'd use a 26" rad since the BB usually produces more heat than SB or slant 6's. Also, are you using a fan shroud? What type of fan drive? Electric? Clutch drive? Direct drive? Cap pressure needs to be around 16 psi.
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#15
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Sounds to me like its airlocked. I always drill a 1/8" hole in the stat so the engine "burps" out the air when first filled up. If not air gets trapped in block,
and you think its full of coolant but its not. The heater not heating and water temps spiking are signs of being airlocked and low on water. |
#16
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Wilks3 has a point worth checking out. While you're doing that, stick a thermometer (anything that will go to 100 C - 212 F or more) into the rad filler neck and see what the temp gets to. Should be close to your t'stat rating. And, sure, blow out the core with low-pressure air as well. If none of that works, then you may have some internal crud blocking flow. Assuming of course you are sure the heater water valve either is non-existant and not just non-operative. (Mine won't open as a result of the vacuum controller switch being stuck, found that out after 100 miles in -5 temps)
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#17
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Quote:
You mentioned new heater core. Sometimes, new products that have pipes, tubes or fittings, will have little cardboard or plastic caps that plug the openings to prevent dirt getting in prior to assembly. Pretty basic, but one may be jammed down in a tube or fitting. |
#18
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Many vehicles ran with the heater core getting coolant at all times. Even my '69 Coronet does not have a control valve. The air door determines if air flows across the core or not.
My '68 Charger has a flow valve and that is because it has A/C. |
#19
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Point taken. Added to files of continuing adult education.
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#20
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these are all good points & correct. back to square one, did the heater work BEFORE you changed the heater core? as mentioned above, maybe you overlooked the plastic plugs that sometimes are present on new core pipes? Drilling the 'stat to avoid air pockets is a great idea which I do myself to avoid much aggravation, however I forgot to mention that. glad someone elses brain was working at full capacity here!
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#21
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is your impeller still attached to your shaft? No circulation would cause an overheat and a cold (although pressurized) heater line.
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#22
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Quote:
ok as far as heater core caps i pulled the two rubber caps off before installation... and my heat control is a door inside the heater box.. that directs flow through the core or by passes it, so i get fluid year round.. its a 69.. |
#23
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Verify that you are getting hot water to the heater core. One of the hoses leading to the core should be damn hot and the other one pretty darn hot. If both hoses are cold, water is not circulating to the core.
Is your thermostat installed upside down, by chance? The "pill" goes toward the block. Sorry, it's a basic question, but sometimes simple things slip by us. |
#24
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ok the hoses are both cool while the rad hose burns a guys hand off...
and the thermostat was working but this summer i know i over heated the engine b accident when i blew out a belt under full throttle on the hiway..now giving eratic readings since....so im gonna replace it tommorow... but does that have anything to do with the heater core?? |
#25
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If the T-stat is stuck closed, coolant will not circulate to the heater. A quick and dirty way to check that is pull the thermostat out and see if you get heat.
Your system may have an air pocket and need to be burped. Did you have heat before the new core? If yes, you had to remove coolant to do the job. Did you get all the coolant back in? |
#26
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the answer to the last is no i think i added fluid but i dont know if it was enough...ill open her tomorrow then..how do i burp the system?? and there was heat in the ld core before she leaked...
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#27
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Burping can sometimes be done by idling the engine with the radiator cap off and the heater control on. When the thermostat opens, you can see coolant flowing in the radiator. Usually, the level will drop. Add coolant to keep the level in sight. Sometimes squeezing the hoses will help expel air. When the level doesn't drop anymore, the system is full.
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#28
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Sounds like it air locked to me. I have had trouble getting the new heater core to fill with coolent. Pull off the hoses at the motor. You should be able to blow thru it with little effort, to make sure nothing is pluged up. If that checks out, put 1 hose back on. Hold the other up high, with a funnel fill the core up till it runs out the nipple on the motor. Hook up the hose back up and try it. Hold your thumbs over the end of the hose and nipple till just before ya shove it on, can be a little messy...Hope this helps ya
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#29
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Quote:
talk to you later |
#30
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ok so i tried almost everything you guys mentioned...even tried a higher pressured cap.....and still no heat...i changed my thermostat to a new one which works great but no heat...any suggestions?? if it is still somehow air locked wont it correct itself eventually??
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