1993 Honda Civic getting HOT

PATHFINDER72

MEMBER
1993 HONDA CIVIC
4 CYL
FWD
MANUAL
188,000 MILES

Car getting hot, new radiator, hoses had no thermostat in it. So installed one got worse in the red. Took thermostat back out, filled up with coolant started with radiator cap off, can see water flowing, tells me pump is good. Even with cap off and running car is still registering hot just below the red. Installed new catylatic converter and o2 sensor, no change. Gauge moves on dash stays in normal spot when first started but rises when driven. Can a car get hot when the radiator cap is off?I am out off answers, what could be the problem?

1 Reply

MHPAUTOS

MECHANIC
31,937 POSTS

HI there,

Thank you for the donation,

The purpose of the radiator cap is to allow the cooling system to run at a pre determined pressure, when pressure is applied to water (your coolant) it raises the boiling temp by about 4 Deg per Lb pressure so if you have a 6 Lb cap the boiling point will be around 22-24 Deg higher this is so your cooling system wont boil at normal atmospheric boiling point, all rather technical hay! But the point is that you must have a working cap fitted or you will boil! This goes for leaks in the system as well these must be addressed as well, are the cooling fans working?
And you best have a head check done as this will detect Co in the cooling system, a sure sigh that you have a head problem, start here.