lately my car has been taking a rediculously long time to warm up to operating temperature (according to the gauge). i've found out that when i slide the temp control to cold (cutting coolant flow to the heater core) it suddenly heats up to operating temp quite quickly. if i go back to hot, it cools down again.

what could this mean??

ps. 95 b18b1, recently replaced thermostat, otherwise stock cooling system.

please help!!!

 

Are you sure you bled out all the air bubbles when you changed the T-stat?

At first it sounded like a stuck t-stat, but then the heater shouldn't matter.

 

i'm pretty sure all the bubbles were out, but that's always a possibility. but usually air pockets make the gauge go all erratic, and make heat output inconsistent. this is not the case.
any other ideas why the coolant would be losing so much heat through the heater core system?

 

bump

 

I'm assuming you have no leaks anywhere. Always keep an eye
on your coolant levels. Any idea when the thermostat was last changed?

 

ya there aren't any leaks, the overflow tank stays at max level. as i said, i recently changed the thermostat, it's now been about 3 weeks since that. please help. it's cold up here and i need my car to warm up!!
thanks!

 

How about the position of the thermostat & gasket. If something prevents the t-stat from closing completely, that could explain it. Defective t-stats aren't impossible, either.

 

do you really think the thermostat is the root of my problem? it heats up fine with the temp set to cold, but when i turn it to hot, the coolant gets considerably colder. i don't think it's a thermostat problem.

no one has ever had this problem?

 

how cold is it where you live? what percent antifreeze is in your coolant? how about gettin a block warmer.

 

was the problem there before the thermostat?

also how cold is it where ya live?

make sure the bubbles are bled out of the system.


make sure you have the proper mix of antifreeze.

 

I agree with everyone:

1. Bleed system of air! There should be a little "vent" fitting to purge air from the system. Consult service manual. VERY IMPORTANT!!!
2. Make sure thermostat is opening during the right temperature. Consult service manual. also VERY IMPORTANT
3. Make sure you install the t-stat with the spring side towards the engine block. VERY IMPORTANT.
4. Make sure water pump is operating. See service manual. Important.
Good Luck.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by superstud &raquo;</TD></TR><TR><TD CLASS="quote">do you really think the thermostat is the root of my problem? it heats up fine with the temp set to cold, but when i turn it to hot, the coolant gets considerably colder. i don't think it's a thermostat problem.</TD></TR></TABLE>Actually, that's a pretty classic explanation of a thermostat that won't close all the way, but otherwise it works.

There's a little bleed hole in the thermostat, with a pin rattling around in it. That has to be towards the top, in fact I think there's a little cavity in the t-stat housing for it. Also the gasket has a groove in it, so it fits over both sides of the rim of the t-stat. If any of that's messed up, it might prevent the t-stat from closing completely. I believe if you try to put the t-stat in backwards, it won't even fit...

The air bleed valve is on the front of the head (on my B18C1), but I usually have to squeeze the upper radiator hose to push the bubbles either towards the radiator or towards the bleed valve. Squeeze the upper hose. You'll be able to hear sloshing sounds if you've got air in there.

FWIW, for other people reading this, some Hondas have the bleed valve near the t-stat, & some don't have a bleed valve at all.

 

thanks, guys. i'll try bleeding the air out of the system again. i'm pretty sure the tstat is in correctly, but if all else fails, i'll check that too!

 

You do know that switching to hot weather you have the blower going or not will pull heat from the coolent in your heater box and cool the motor back down especially in the winter. That is why some people race with the heat **** over cause it helps disperse heat in the coolent.

The air mix door opens just no fan to pull it into the passenger compartment at a high speed.

 

yep, i know whether the blower is on or not it routes coolant to the heater core, but that still doesn't explain the drastic drop in temperature. i small drop is expected, but it shouldn't be enough to move the needle at all, let alone to drop it down nearly to the bottom. as far as i know, factory temp gauges are calibrated to stay pretty close to the normal position unless the temp is way off, so you know when the needle sits abnormal, something's definitely wrong.