While I was driving my car today ('90 Civic EX, 1.6L, Auto, 201k miles), it starting running hotter than normal. I turned the heat on full blast and the temp gauge lowered back down to normal. About 2 blocks from home, I turned the heat off and sure enough, the needle began to climb. By the time I pulled into my driveway, the needle was a little past horizontal (it usually stays below horizontal all the time) and some steam came out from under the hood. I shut it down and popped the hood. There was coolant spatter on the front of the motor below the valve cover and what looked to be evidence of spray coming from the upper hose on the end connected to the radiator.

I allowed the car to cool for 90 minutes and popped the radiator cap. The radiator was a bit low, a quart, maybe more. I filled it, bled it and replaced the cap after the motor was thoroughly warmed up. I ran the car for a couple minutes at 2500 rpm and got a little steam coming from the radiator cap. I continued to run it for another 5 minutes at 2500 rpm and got little to no steam from the same area. Also, the temp. needle never moved from it's normal position. There are no leaks coming from the radiator, nor any spray from any of the hoses.

Best guess is I'd say the radiator cap needs to be replaced. Based on my description, would you out there agree with me? Or might there be something else going wrong? I'm sure it happens but I've never heard of the radiator cap being the sole problem.

 

Found the real problem. I was holding the throttle from the drivers side and saw steam coming either from or near the cap. I switched to the passenger side and held the throttle. Saw that the steam was coming from a very small leak on the top of the radiator. Upon closer inspection, there was also coolant seeping out. When I wiggled the radiator a little, the seeping became a spray. So, the radiator is worn out. I'll be replacing that, the thermo and both hoses today.

 

Just finished doing the work. After replacing everything I filled and bled the system and ran the car for about a half hour. Everything seems to fine with one exception: I'm getting some steam from around the fill hole of the radiator. Is this normal after doing the work I just did? There's no leaks or seepage (best as I can tell) from the radiator or hoses.

Should I be concerned?

 

maybe its just because its cold outside?

 

It's about 60 degrees outside.

 

oh lol.

did you get a new radiator cap along with the new radiator?

i was told that buying both increases the life of the radiator.

 

The radiator didn't come with a new cap but I did buy one and put it on. I figured if I'm gonna spend $95 bucks on a radiator, might as well spend an additional 5 for a new cap.

 

you should be fine may just be some coolant you spilled on the rad.

 

Yes it could just be stuff on the outside. Keep a very close eye on the level for a while, like check it every morning before you start.

 

My plan is to check it every night before work and every morning after work for the next 7 days.

Thanks for the advice.