I have a 1998 Z/28 with alot of bolt ons, see list below. About a month ago the PCM started throwing out P017 & P0174, Fuel Trim Lean Bank 1 & 2. I checked for vacuum leaks with carb spray, in common leak areas, replaced O2's, replaced PCV Valve. I cleared the code and all was good untill I would get on it. The SES light would come on. I disconnected the battery and reset the PCM, and the light hasn't come back on. Then about a week ago, I opened her up on the freeway, like 140MPH. As I started slowing dow, I noticed the temp gauge rising. Just before red zone, I pulled over and let her cool down. any way I got her home, and she has 125,000 miles, so I thought it's gotta be either water pump, or thermostat. I went with the Meziere Electric pump, and new therm. I figured it was all good. Took her out, and she overheated, and blew the radiator. Pump is working great, therm is brand new,and everything is installed correctly. I replaced the radiator with a Be Cool and thought, no more problems. Sure enough, she still gets way too hot. The only other thing I can think of is that the LS1 is still running lean, (with no codes?), possibly clogged cat and/or cat's.
I ordered new cat's but what do you all think.With all the airflow coming in, it makes sense that it is running lean, but I just don't know. I would appreciate any help, for I am out of Ideals. Oh yeah I also just order a Ractronix fuel pump, but I have hooked a fuel pressure gauge up to the fuel rails and I've got good 60 PSI witch drops a little (58 PSI) under load. Could this also be a bad regulator???

1998 Camaro Z/28 Mods.
1. SLP Air Lid
2. SLP MAF Sensor
3. SLP Air Bellow
4. SLP TCM ASR Reversal Module
5. SLP Fan Over Ride Switch/Harness
6. SLP Hurst Shifter Ball
7. SLP Cold Air Induction (Not Installed)
8. SLP Strut Tower Brace
9. F.A.S.T. 78mm Billet Throttle Body
10. EGR Tube Cut
11. ASR Underdrive Pulley set with Alternator Pulley
12. Meziere Electric Water Pump
13. Be Cool Aluminum Radiator
14. K&N Air Filter
15. Flowmaster
16. Mindon 160 degree Thermostat
17. Racetronix Electric 255 lph Fuel Pump w/ separate 12v line (NOT YET)
18. MSD Coil Packs
19. MSD Wires
20. NGK Iridium Plugs
21. ZO6 Clutch
22. Eibach Pro Springs
23. Edelbrock Torque Arm
24. Edelbrock Pannhard Bar
25. Bilstein Shocks
26. Superior Rear Axles
27. 17” SS Grey Rims
28. Skip Shift Eliminator

Parts Replaced (125,000)
1. Rear Axle Seals
2. Rear Pinion Seal
3. Clutch Slave Cylinder
4. Rear Brake Pads (Carbon Fiber Composite)
5. Oxygen Sensors (Bosch)
6. PCV Valve
7. Radiator Hoses
8. GM Corvette LS1 Water Pump Gaskets

 

Are you sure the fans are coming on? Does it heat up at high speeds or low, or both? Your mods should not be enough to cause it to run lean enough to overheat, although that MAF will throw those codes unitll you get it tuned. My advice is to find sombody that has either LS1 Edit or HP Tuners and let them tune and data log the car.

 

Radiators wont blow from overheating. The radiator cap will allow steam out as soon as the pressure is above 16 psi above atmosphere or so. The most likely reason you are still overheating (you may have already discovered this by now) is that combustion gasses are being vented into the water jacket. This is caused by blown head gaskets, cracked heads, and split cylinder bores. The combustion gasses in you cylinders are compressed to about 180 PSI above atmosphere before combustion, and I have no idea what the pressure would be post combustion (it'd be huge though)... that's the kind of pressure it takes to blow a radiator. Sorry to say, you're fix wont be a bolt-on. You're gonna have to pull the heads.

 

I tend to agree with Nitrojunkie, especially since it overheated all of a sudden under load. You can get the coolant tested for the presence of combustion gases.

 

if I remember right the the combustion chamber's reach 1500 to 1600 PSI after ignition on a N/A motor and 1900 to 2100 on a turbocharged or supercharged engine... so yes that kind of pressure will blow stuff up for sure...

but ya you've got a head leaking some where.. check your oil for trace's of coolant and have your coolant test for gas's and other thing's that shouldn'e be in it...