93CamaroLT1

It's really cold outside and my original thermostat got stuck open on my 99 Si, so I took it in to get it replaced. When I got it back it was overheating while driving, unless the heat is on in the car (I got it past 3/4 of the way towards hot). When I popped the hood I noticed the upper radiator hose is hot but the lower radiator hose is cold. What does that mean? I looked in the Chilton's manual and it says if the upper radiator hose is hot that means that the thermostat is opening, but what does it mean if the lower radiator hose is not hot? Did they somehow put the thermostat in the wrong way?

itsnotfast

Sounds like the thermostat is not opening. You might have to bleed the system. There should be a bleeder screw on the water neck going to the upper red hose. Let the car run for a while (not to the point of overheating) crack that bleeder open and see of you get any air. It could also be a faulty thermostat.

nothing_shocking

What you should do is take it back to the shop and have them fix it. If it wasn't doing that before, they screwed something up.

Easier then messing with that bleeder would be just take the cap off the radiator, turn the car on, let it warm up COMPLETELY (the fan turns on/off twice) and watch in the radiator to see if there are any bubbles. By that time the lower hose should be hot. Also make sure the car isn't overheating while doing this.

93CamaroLT1

Thanks for the replies. They said that they were replacing the thermostat when I dropped it back off slightly before I made that last post, I was just hoping that they were on the right track seeing as how these guys really don't appear to know what they are doing (e.g. I took the car in and the clown drove sat around revving the motor and drove around for around an hour and couldn't get it to overheat but had the heater on. I turned off the heater and had it past 3/4 of the way to Hot in about 5 minutes).

delsolproblems

The lower hose shouldn't be hot. Coolant enters the radiator from the top, it cools the liquid and then the coolant comes out the bottom, no longer hot. Make sure the fan is coming on. Check the temp of the motor to make sure your gauge is giving you the correct reading. You might try replacing the thermostat again or at least checking for a part number on the one you have to make sure the right one was installed. Make sure coolant is flowing well through the radiator and lower hose

turbodcxbro

iTrader: (1)

My car is doing the EXACT same thing after a new T-stat install and coolant flush. I have no heat and my lower hose is ice cold. I'm leaning towards a bad water pump...

93CamaroLT1

Turns out it was that the new thermostat was not opening (at least that's what the dude who worked on it said). I took a look at the lower hose and when the car is warm the lower hose isn't hot, but still is relatively warm and not ice cold like it was before.