Mistermark

I have a 93 dx and Ive been noticing, i haven't been getting much heating in the car as i used to, on the highway its good, and theres heat, but on the streets, its almost blowing cool air.
any ideas of what it could be?

Mistermark

anyone?

lloydmst

Mine is doing the same thing, I start my car up and let it run for 40 min before driving, Car temp says almost half, But the heater is blowing cold. Rev it up and hold for 2 min or so and then it starts to blow warm to hot. Going down the road its not bad, but when going down a hill it gets cold again. Take off and warm again. 1993 honda civic coupe 2 dr. d15b7 headers, cold air intake, high pro cat, performance muffler. New timing belt, water pump, thermostat, plugs, wires, valve cover gasket and seals and radiator. When I went to work today 48 miles away from home at 75 mph. when I pulled in the lot, I opened the hood and felt the upper and lower rad. hoses. top one was hot bottom one was cool to cold. Same with the heater hoses one hot and one semi cold. If I rev it up to 1500 - 1800 rpm's everything gets hot and heater works. But at idle, Hardly nothing. I did use the Dex cool/regular multi mix type anti freeze you know the kind you can mix with either. And I mixed it 50/50 with water. Any one out there who might have an idea whats up with this thing. Oh and I did flush everything to make sure it was all flowing good. And it was. Heater core flows free as Radiator does too. Please help.

lloydmst

Well I have now changed my heater core too, So let me sum this up. NEW! heater core,radiator,thermostat,radiator fan switch,water pump, timing belt. And bled system. And STILL no heat unless you are in the throttle. Temp gauge reads almost half. When coming down a hill it starts to blow cold, If you downshift (automatic) it will get warm again. I start my car at least 30 mins. before leaving. And it will not clear the snow or ice from the windsheild. I live in PA. This is the first honda I have owned. And this is the first *** backward cooling system I have ever encountered. The thermostat in the back of the engine instead of at the highest point. Its also connected to the lower radiator hose, which most are connected to the top hose. That is why I was wanting a picture of someone elses thermostat housing. I believe this engine was changed before I got it and maybe they have the hoses back there hooked up wrong. I hate to get rid of this car, it runs great just dont make heat sitting and idling or coming down hill. I changed all the parts because of this very reason. But its no different as of yet. The car is warming up on the gauge and the engine is very warm the fluid is circulating, the hoses are very warm in and out of heater core. Its like a air pocket in there, but like I said I have bled this for hours. I used the bleeder and a tall funnel in the radiator full of fluid and waiting on the bubbles to stop. Anyone else done all this and found the problem. Thanks for taking the time to read all this.

shortlid

For now you can try puting a peice of card board in from the the rad. to cut down on air flow! Temperay fix I know but for now might work, I do it up here in New Hampshire on 0 and below days!

alleyezonme

my heat started to do that when the headgasket was going... don't ask me how, there wasn't even oil in the antifreeze or anything like that... just lack of heat. It would even overheat on the temp gauge and still blow cold air!! Just something to think about. I think they make a tool that bleeds for you, like kinda sucks the air bubbles out or something?? Maybe I am just making that up, but it sounds like there is still air in there somewhere.

BubblegumTate

Probably when your head gasket was going, it wasn't leaking to the inside, it was leaking to the outside -- probably slow enough that it was only leaking while under pressure, when you were driving and not looking in the bay to see the leak. The heater hoses connect to the head, so that could cause enough of a pressure drop in the heater hoses to have crappy coolant flow to the heater core.

fraknstien

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by lloydmst &raquo;</TD></TR><TR><TD CLASS="quote">Mine is doing the same thing, I start my car up and let it run for 40 min before driving, Car temp says almost half, But the heater is blowing cold. Rev it up and hold for 2 min or so and then it starts to blow warm to hot. Going down the road its not bad, but when going down a hill it gets cold again. Take off and warm again. 1993 honda civic coupe 2 dr. d15b7 headers, cold air intake, high pro cat, performance muffler. New timing belt, water pump, thermostat, plugs, wires, valve cover gasket and seals and radiator. When I went to work today 48 miles away from home at 75 mph. when I pulled in the lot, I opened the hood and felt the upper and lower rad. hoses. top one was hot bottom one was cool to cold. Same with the heater hoses one hot and one semi cold. If I rev it up to 1500 - 1800 rpm's everything gets hot and heater works. But at idle, Hardly nothing. I did use the Dex cool/regular multi mix type anti freeze you know the kind you can mix with either. And I mixed it 50/50 with water. Any one out there who might have an idea whats up with this thing. Oh and I did flush everything to make sure it was all flowing good. And it was. Heater core flows free as Radiator does too. Please help.</TD></TR></TABLE>


sounds like the same problem i have right now, i posted https://honda-tech.com/zerothread?id=1885500 few days ago , theres some talk about a "lever" in the post, but i never got a chance to check it out, keep us updated

fraknstien

maybe the valve is broken..

94eg!

iTrader: (2)

If your engine coolant temp won't stay up, your thermostat is stuck open. Replace it (takes 30 minutes including drain & fill of coolant)...

If your engine temp is up, but the heater doesn't blow warm (or won't stop blowing warm), your heater control cables have become mis-adjusted. Your temp lever should slide all the way to both hot & cold ends and "click" into place. If it doesn't, either the coolant valve cable ends, or the air mixer door cable ends, are not clamped in the right place. Make sure when the temp control is in the hot position, the coolant valve in the engine bay is FULLY open (and fully closed on cold). If it looks good, then mess around with the air mixer cable under the passengers dashboard. If you still can't get it to blow hot, then check to make sure the opposite ends of both cables are attached properly to the temp selector on the heater control unit...

Personal Experience:
My 94 Civic heater wouldn't shut off. It turned out to be the metal bracket that holds the coolant valve in the engine bay was bent up. This meant that even though the lever was all the way to cold, it wasn't closing the valve allowing coolant to constantly heat the heater core.

Also, this car wouldn't stay up to temp because my engine swap came with a bad thermostat. My car wouldn't blow hot air unless I was on the gas. $18 at the local Acura dealership fixed this problem.

My 89 CRX had one of the cable clamps on the temp selector break off (twice now). Once I set the temp to cold, it wouldn't go back to hot since the cable sleeve wasn't held in place (the whole cable & sleeve just moved back & forth).