another LT1 overheating problem- Inside please

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Ok- i have a 94 LT1 with a 97 block w/ stock aluminum heads, mods are in my sig.

although it has an electric CSR waterpump, and the radiator and rad. hoses are about 8 months old. I just replaced the thermostat about 3 weeks ago.

Anyways- saturday the car all of a sudden started overheating really fast, like 15/20 mins of driving and it would get hot, i couldnt even get home saturday night, had to park it at a friends house.
A buddy that has a 97 LT1 that races told me to clean the metal pipe that connects to the back of the heads and then clean the bolts and what not.
So i did that, and the water flowing through that pipe and into the radiator seemed to really be flowing good now. Well i filled it up with coolant, let it warm up, and went driving around and got it to heat up to the 1st mark above 160, then i stopped and opened the bleeder and let all the air out and filled the radiator up the rest of the way with coolant.

Well, this was fine for about 20 mins and then it overheated again.

We arrived at my girlfriends dads house and the car was pukin coolant out of the overflow, and startin to get up twards the red mark, so i shut it off as soon as i pulled in the drive way but kept the key on so that the fans and the electric waterpump would run and circulate the water.

Well - we let it cool down a bit, then took off the radiator cap- when we looked in- it appeared that no coolant was lost..., but i start the car up again after it has cooled back down to like 170 or so ( we stuck a thermometer in the radiator to read the temp) and started it back up with the cap off, coolant started coming up out of the radiator cap hole, and started goin into the overflow, but not fast enough, then it started overflowing from the radiator cap hole and just running everywhere.

We let the car cool down again, and i pulled out the 180 themostat, and put the housing back on. Took it for a drive, and in about 10 minutes the gauge in the car showed that it was getting hot again- goin up twards the red mark, so i pulled it back in the driveway and shut it off and the key too so the waterpump was off also, we poped the cap off the overflow and the tank was full of coolant, we stuck the thermometer in there and it showed about 150*, then we opened the radiator cap and of course- it was pressureized in there and some sprayed out, but when we got the cap off and stuck the thermometer in it the thermometer read 180*..

There is no water in the oil either..

I took the CSR pump out of the housing today and then turned it on- it spins, but im going to have it rebuilt anyways because it is atleast 3 or 4 years old..

the housing is all nastified, and pitted and inside the center of the housing where the impeller would sit, down in the groove in the bottom there was some coolant , but inside that there was a white substance. looked like eggwhites floating around when you scramble them in water and whisk them with a fork...

the car is firing on all cylinders also w/o missing a beat..

Anyone have any sugguestions?? BTW:- the car will sit and idle right at the 2nd mark on the temp gauge on the dash. but when you go driving is when it heats up. It seems like it will sit and idle there at that mark for like 15/20 mins and not get warm, but when i take it on a drive in less than 15 it over heats..

after i get this all straightened out im going to put in a 160 thermo- thats what the computer is programmed for. and a new clutch, but i have to figure out this cooling thing first....

 

Sounds like you have a bad waterpump. Here's a few things you could also do/check. You could replace the thermostat to a 160 degree one (fairly inexpensive), you could buy a fan switch that you can switch on your fans whenever you want (also not to pricey), also you can flush and fill your entire cooling system (also cheap, and sounds like it would be a good idea). Also, you can bypass your Throttle Body (cheap and easy). Past that you can have your computer tuned to have the fans automatically turn on earlier, and have adjusted to a cooler (160) thermostat. Or change to a larger radiator (expensive, and unlikely that you should need to). And that's pretty much the entire cooling system.

If you do change the waterpump, its highly recommended to change the opti as well, seeing as how it is right there, and a bad waterpump can usually take out an opti anyway. Good luck.

 

Well,- I already have a TB bypass, i have taken the waterpump housing off- I have the CSR electric conversion- It works just fine, but the housing was all pitted and nasty, i pulled the pump off the block and its all nasty inside- looks like when u mix orange and green coolant together..- nasty stuff..- so, what im gonna do is or what im doing is- lettin all the liquid drain out over a few days, then ima blow it out w/ the air compressor, i've got the radiator hoses off and im going to blow them out too and flush the radiator, im also gonna blow air through the heater core- at a low pressure- to see if there may be a blockage.. The computer has been tuned for a 160* stat, and the fan/waterpump are wired so that when i turn on the ignition it comes on the other fan comes on when i run the A/C and if the car gets hot it kicks in...

I bought a new waterpump housing ( stupid me- bought one for a vette, thinkin it would b the same, but NOO!) Anyways- its being machined to fit the camaro and having higher flow elbows put on it...

I also bought a 160* stat im going to put in, and a new temp sensor that goes in the waterpump housing and a new temp sensor switch that goes in the block btwn the 1 & 3 cyl's..

 

Only thing I would do different, is use water to blow everything out instead of air. It will do a better job of breaking up any possible blockage that might be in places.

 

thats probably what im going ot do anyways- i dont feel like movin all the **** to get to the air compressor.. lol