I've noticed over the past few days that my car was getting a little warmer than normal. It usually stays right around 160* or so. Both fans are wired to the ignition, airdam is in place, I have a 160* thermostat and the waterpump was replaced Dec. 2003. The radiator was stripped down and boiled out summer 2003.

After I start the car up and drive down the road it likes to go up to about 220* (45mph +/-) and then come back down kinda quickly. Never done this before, it usually never goes over 160* even in hot weather, remember both of the fans are running as soon as I first start my car. This has happened for a few days now.

Skip to tonight, kinda cool outside. I left a friend's house and while driving through the neighborhood (long ways out...about a mile stretch w/ random stop signs) my car started getting hot slowly, 220*.....230*....240* I started getting worried. I turned on the heater full blast and only cold air was coming out. Car seemed to be heating up during acceleration, so I stopped for about a minute just idleing and the temp went down some. I started to drive again and the temp held steady for a few seconds and then started going back up fast. I turned my car around and headed back to my friend's house, hitting 260* (red pegged out) 2 times on the way back. I would stop and let the car idle and it would cool down some and then I would drive some more. By the time I got back to my friend's house, the heater was blowing hot air like it was suppost to. The extremely weird thing was driving home (after I let the car cool off), it never once went over 160* even when I got into my neighborhood and was driving slow. I did notice a very, very slight smell of antifreeze for a few seconds while in my neighborhood but nothing was leaking when I parked the car.

I don't know what to think. This confuses the hell out of me. I start thinking a few things....bad temp sensor, stuck thermostat, blown heater coil, leaky headgasket or hose, fan motor going out (although I hear them running when key is on the "on" position). I'm stumped. What do you guys think?

 

samw problem here. any help would be nessesary.... got home tonight afterowork and the temp gauge was maxed out.... got home tonight, popped the hood, felt the radiator cap, and it was cold...which was wierd. the overflow had bit of steam coming out though. i decided to be dumb and open the radiator cap with a rag over it, and steam steam/coolant came gushing out. kinda wierd since the cap was pretty cold. radiator is about 1.5 year old, water pump has about 20k on it, and i just changed the thermostat about a month ago. this is really starting to **** me off cause my car have been giving me so many problems lately in the last couple months. i have no bubbles/foam in the oil and everything else seems fine. any help would be appreciated. im thinking possible waterpump, clog somewhere. might change the thermo down to a 160...would be a smart idea for a stock LT1 with 126K on it?

 

Have you guys tried bleeding any air out? Maybe there is a little air bubble trapped in the system somehwere.

 

Have you replaced your radiator cap? it can cause problems too.

 

I think I might have figured out my problem (last weekend). My thermostat housing is leaking at the base where it mates to the intake. It appears to be a small leak as far as I can tell. The radiator was actually pretty low on antifreeze/water even though the overflow tank had plenty of antifreeze/water in it. I've been keeping an eye on my radiator fluid to make sure it doesn't get low until I figure out and fix everything.

There has to be another problem somewhere besides the leaky thermo housing. I'm gonna change out the radiator cap and see if that helps matters any. All hoses look fine and don't appear to be leaking and my oil is good so I doubt it's a headgasket.

Any more advice is appreciated.

 

Your leaking thermostat houseing is keeping the coolant from being drawn back into the radiator when the car cools off. You are drawing air in at the leak. I would change the thermostat. Your description of only getting hot sometimes sounds like a thermostat that is not opening all the time. If you change it be sure and use one for an LT1.

 

ill check my thermo housing tomorrow. on the topic of a thermo for an LT1..i recently read shoebox's how to on the thermo swap. i wasnt aware that the LT1 had a longer thermostat. would any local auto parts store carry one made specifically for an LT1 cause i just changed it with a 7 dollar 180 stat last month. gonna work on this problem tomorrow morning so any help by then would be greatly appreciated.

 

An auto parts place should have the thermostat. You will probably have to get it at the parts counter. I haven't ever seen one in the thermostats they have in the aisles. You should change it if you have a regular one. I don't know the effect of using a regular one but the cooling system on the LT1 is designed to use the LT1 thermostat not a regular one.

 

By the way if I remember correctly the LT1 thermostat comes with an o ring gasket. If you are using a regular gasket and your housing is leaking that may be the reason.