Hi,
I have a 1998 Honda AccordLX with the 4 cyl. engine. I have been going nuts trying to get a new thermostat to open. The upper hose gets hot while the lower hose stays cold. I am on my second thermostat. I have opened the bleeder multlple things to expel the air but the lower hose remains cold . I have gutted the original thermostat, installed it and everythings seems fine with coolant visible and flowing as observed with cap off and both hoses about the same temp. As soon as I install the new part, the lower hose remains cold and it seems like excessive pressure results.

I have driven the car about 20 miles with the gutted thermostat with no problem at all other than the temp. gauge reading a little cool on a cold day, but still supplying good heat inside the car. I sure would appreciate some feedback on this subject.

Thanks, John

 

What is the temp gauge showing when the top hose is getting hot?
When you install the T-stat the thermal coil/spring side is towards the engine block?
The coolant system does normallypressurize 12-14 PSI to raise the boiling point of the coolant.

 

Thanks Hondadude,

I think I may have found part of the problem in a slight horizontal split in th upper tank which was causing the steaming at times. I still feel that the lower hose has to get a least warm to the touch after the cycling of the thermostat.

The temp gauge always reads as normal and the thermostat is as you stated as far as position. I will install a new radiator and take it from there. Thanks again, John

 

any update on this my friend? Im having overheating problems of my own. Im going to check and see if my lower ghose remains cool. My temp gauge shows its at normal temp but I think im overheating. New engine swap and everything too... hope I dont BHG this one

 

If you really want to know what temp the car should run at I used a infrared thermometer and got 178* on the upper hose and around 150* on the lower hose.

 

Jp98,

I have also replaced heater hose that goes from the head to the heater control valve.
Seems like all is well with the lower hose getting alittle warm after my wife's trip to work and back. I cracked the bleeder valve just to the right of the thermostat housing slightly as I was filling the system, making sure that the air was purged, making sure thatcoolant was flowing freely before I closed it.

I will definitely get an infared tool such as finch13suggested. They are pretty reasonable at Home Depot and would seem like a handy tool to have.

John