I have 2003 G35 Sedan Manual and its starting to over heat. I noticed a small antifreeze leak from the bottom of the radiator where the plug is. I noticed no other leaks anywhere else. I was thinking it was a hose, I checked those and they seem to be fine. So I bought some Fiberlock and poured in the radiator and also added some coolant to the reservoir. Now it over heats in ten minutes tops. Could it be the thermostat, too much coolant in the reservoir or......? Need some help

 

Big mistake pouring anything into the radiator!
Possible now you might need a replacement radiator if you clogged it up with that s#it

With a fourteen year old vehicle it is probably time for not only a new thermostat, but a water pump, a new radiator cap, fresh coolant, new radiator hoses and a complete flush

Follow the troubleshooting steps in the FSM

Telcoman

 

What steps did you take? Did you disconnect the radiator hoses that would introduce air in the system if so. If you poured that stuff in as is you could be clogging up the passages with it. I would never use that stop-leak stuff. You could have replaced that radiator for about 100 bucks in parts.

 

I didn't take off any hoses at all. Poured it in the radiator. Guessing that wasn't the smartest thing to do. Probably needs to be flushed then a water pump replacement?

 

I would do the following tests then proceed from there:

1. Rent a block tester it's about 20 bucks. You take out some antifreeze and while the car is idling you suck in some air and it changes colors if there is exhaust gas. If it changes you need a head gasket and you're SOL for an easy cheap fix.

2. Rent coolant pressure tester. Hook it up and pump it to about 15PSI and see if any coolant leaks. You can tell if it's a hose, radiator, heater core, etc...

Feel the hoses when the car is running or they similar in temperature?

After doing those two tests proceed below to:

I would buy a new radiator, thermostat, and radiator cap. You can get all that for about 100 bucks.

You can check the water pump by opening up the black cover on the right front side of the engine. But, you need some long M8 bolts and have to slightly play with the timing chain to get it out. You can accidentally turn the car over and possibly skip your timing (don't ask how I know). If that happens best thing is to take everything apart and re-align everything back (I had to do it when my water pump went bad and skipped some teeth changing it). However, I'm not sure of your mechanical skills, I would leave checking/replacing the water pump to a pro.

I would then take out the old radiator, thermostat, and try flushing that stuff out. But, it could cause that stuff to flow through small passages, so I'm not sure I would do that just yet.

Replace said parts and spend a lot of time getting the air out.