My car is a 96 lt1 z28.It is a full bolton hot camed car.I first thought it might be the radiator cap not letting presure out and causing it to force fluid out of the overflow.But I replaced it and the dam car keeps overheating.I drove it today for 60mial's on the freeway at about 90mph the car never heated up past 180 untill I got off the freeway then after about 1m of city driving the car begins to dump water out of the overflow and the tep reaches about 195 and I shut it down.So after this I decided to hook my fans up to a switch so I can control when they are on.All this did was help me cool it off faster when it overheated after I got off the freeway on my way back home from the 60mial drive.There is no blown head gasket and I do not think I spun a bearing the motor is quiet and the oil presure is great.I am begining to think the csr water pump is not pumping fast enough and the only reasion it is fine on the freeway is because of the 90mph wind.What do you think? Thanks

 

If it's forcing coolant out to the overflow tank and the temp is only reading 195, something isn't right... It should only do that if the temp reaches 220-230 assuming the radiator cap holds pressure...

Did you check the obvious stuff like a plastic bag blocking the radiator and such???

Did you change the thermostat to a SBC rather than a proper LT1?

 

HOW do you know it isn't a gasket?
Radiator stopped up?
Do a pressure check.
Is the underneath air dam in place?
Check your EWP.

 

The tstat is a new lt1 160.The radiator cap is new.And it can't be a head gasket because it is not burning water and it never had a smoking problem. I am going to do a pressure test today. There is one thing I noticed; it looks like the overflow line and the tb line are switched.I think the overflow line should be at the top of the radiator near the cap and the tb line should be just about 1 inch under it. I am going to go ahead and switch it and see what happens.

 

A gasket can just puke water out and overflow your jug and leave the rad very low.

 

are you sure your not just overfilling the radiator? when coolants pours out is the coolant sensor light coming on the dashboard? it should definitly not be pouring out at 195 sounds like you either have too much coolant or maybe a stuck thermosat or something

 

I did a presure test and it turned out good.But I did switch the lines befor I did the test.I really think the problam was caused from the lines that got switched whin I did the cam install. I think sence the overflow line was on the bottom it was forcing the collant into the overflow causing the radiator to run dry and over heat.I let it set and run for about 15 min and the temp never went past 170. I am going to take it for a drive right now and see what happens.

 

Ok I think its fixed. It dident even attemped to overheat.I was starting to think I had a bad head gasket. I kinda wished it was a head gasket because then I have a reason to upgrade my heads. It turned out to be the lines from the overflow and the line from the tb were switched at the radiator.I guss I am going to wate utill xmas to get a set of LE heads.

 

I'm glad I found this one. lol I just changed the opti and managed to cross those two hoses around on my 94. glad it wasn't something more major I just finished the heads 2 months ago

 

I have a friend that done that(swapped hoses by mistake) and warped a head when it overheated. Be careful not to overheat them.

I've overheated mine when a cooling fan fuse blew....didn't know it and was letting it idle while I was watching the computer screen. Smelled coolant, look up, and saw the gauge pegged at 260+. It did warp both my heads and I had to get them decked.

 

is there a diagram of the proper hose routing? Im in the middle of a head/cam install and would hate to have this happen to me after all the hard work and money ive put into this

 

Shoebox has all this stuff on his site.... always a good place to check for the info you need:

http://shbox.com/1/95-97_hoses.jpg

 

http://shbox.com/1/95-97_hoses.jpg

is that a good diagram?

 

LOL, it should be. It cam from GM. Is there some reason you think it is not?

Here is one for the heater hoses:

http://shbox.com/1/heater_hoses.jpg

 

Looks like Injuneer beat me to posting up the diagram, I didn't even know he posted the same one when I replied . However, no. There is no reason I think the diagram would be no good. I was just wondering if the diagram showed the relevent hoses that the OP was talking about or not