Recently my car was over heating, and the only issue I could find was a small leak at the waterpump gasket. So I replaced the water pump, and the thermostat. The car stays cool while driving, but when I get into stop and go traffic, it starts to get up over 210 pretty rapidly. Typically the car stays @ around 170 degrees and never above 180. I also replaced the 2 coolant fan relays, since I think they were both bad. I have verified that the fans do run now.

My only other concern is that maybe when I replaced the water pump, got made the coolant mixture too rich? Could this cause this slow overheat issue?

Also, would bad Temp sensor be to blame?

Adam

 

Mixture is not the problem, could be the sensor, might as well replace it, it is the one on the head that is for the gauge. Could also be air in the system, did you bleed it after changing all that stuff? That is the most common problem, I would suggest draining the system, refilling it 50/50, or mostly water depending on where you live, then running the car with the radiator cap on for a minute, take it off, top the coolant off, put the cap back on, then loosen the screw located in the line that would go into the TB until coolant starts flowing out instead of air.

 

I had an overheating prob in my '93 after i changed the heater core, so i changed the water pump and put a 160* thermostat in it and it would still overheat if i sat still, then the water pump litterally blew the lower radiator hose fitting off (hose and all) and left me stranded . turned out it was the radiator, but i spent close to $1000 fixing it. might wanna go get your radiator power flushed or rotted out (usually not that expensive..like $125 for rotting it out and $25-$50 for power flushing). Just a thought

 

Hi Guggi97

I have had two problems with my LT1 overheating. Had found hose was mangled and restricting flow. This was the line leaving the top port of the water pump and going to the heater core. The short section of hose coming from the bleeder section to the water pump had become delaminated inside the hose and clogged up the flow. This short section of hose will feel flimsy if you squeeze it. Also be sure to bleed the two screws as mentioned in the last reply. Another tip, If you take and replace a hose, try using screw type hose clamps as they are easier to remove and replace than the springloaded hose clamps.
The other hose that gave way was a 3/4 hose attach to bottom port of the water pump.

 

A coolent temp of 210 or even 225 isn't really overheating. In hot weather it's not atypical. As long as the temp goes down when the fans come on you should be ok.

I've had problems with my fan relays though too, so you're not the only one. A mechanic I asked seems to think it's a voltage problem....I've lost my fuse twice now.

One other thing. When was the last time you flushed your coolent. If you go over the recommended time for it the leak stopper that comes from the factory (and that most shops add) will begin to coagulate and clog up parts of the system. Had to reverse flush my heater core to get the gunk out and also lost my low coolent sensor.

 

My OBD1 ECM is programmed to turn the fans on @ 160 degrees. So, knowing this, it does become concerning when the temp goes up to say 225 or so when for the last year it has never gone above 180, and will not go down until I get on the road. I did replace both the upper and lower larger radiator hoses when I did the pump. There seems to be a lot of "floaty" material in the coolant. The power flush is starting to sound like a good idea!! It is odd that the issue does not happen until I have driven the car for a liitle while. I can sit and idle for ever without any issues.

 

Are you sure your fans come on at 160*? That means they're probably running all the time. Even with a 160 stat and fans set that low it's unlikely you'll maintain a temp below 170*. The lowest mine settles at is 175*-178*. That's moving. In traffic the low speed fan will come on at 195 and off at maybe 180 or so, but I've changed the programming.

Anyway....do the flush....book says 65,000 miles or 4 years I think.

 

yah, OK, I think We found the issue. I'm @ 115,000. Never been flushed!

 

mine did the same thing...i replaced the thermostat and installed a fan switch just incase....no issues with overheating since

 

yeah a flush would be a good idea also another thing to look at is my radiator and ac one was full of lil rocks, and dirt so air could not pass thru easily...

 

if you use a manual fan switch to turn on the fans, will the
computer setting still work? i thought that once you had a manual switch for the fans that you dis-able the computer from turning on the fans, I have a slp switch, if didn't turn the fans on
manual would they kick on from the original setting from the factory 220 degrees or would the car overheat?
zoso

 

i didnt buy a switch...i taped into the fan ports. The "H" and "J" ports are what make the fans come on. My fans come on at stock settings, or i can cut them on earily

 

If you have your fans set to come on at 160, they would run all the time. There is no need to have them come on that soon.

By your first post, it sounds like a normally functioning stock system.

 

lt1's run hot. Its just normal operating temps. All those things help,but they all came from factory this way. Notice how many ppl have the same problem???

 

Ild say radiator is crapped up.