Problem with my 3kGT it overheats to 3/4 of gauge!! Help? - Page 3 - 3000GT/Stealth International Message Center

Fernandoz3kGT · 11-12-2012, 07:27 PM

Overflow tank is the one inserted like in the front bumper? seems that i need to remove the bumper to get it out and clean it? Can anybody correct me if im wrong? I will replace the coolant tomorrow and replace radiator cap and coolant temp sensor like you guys said and post back results.

dbest671 · 11-12-2012, 08:16 PM

Oh yeah, the 99 coolant tank is in a different place... IDK if you can remove it without removing the bumper. But if you have orange/brown stuff in your coolant system, I bet you have a mud like stuff on the bottom of your coolant overflow.

Grandpa Poser · 11-12-2012, 09:02 PM

If its that bad a system flush would be in order. You can DIY but I prefer to have a rad shop do it.

Grandpa Poser · 11-12-2012, 09:50 PM

Sorry, I must have missed the part about you already doing the flush. Did you use a solution or just fresh water?
Now the good stuff. Several tests.
After your car warms up feel not only the hoses but the top and bottom tanks as well, feel both ends of them as well as the middle near the hoses. Also feel several different areas on the fins. You are checking for temperature differences that may show blocked tubes. Entire top should be warmer than entire bottom.and there should not be any cool spots.
You already checked/replaced stat and cap so you can skip that test. Is your overflow bottle empty or loosing coolant? When you flushed/filled did you burp the system? Air trapped in the heads can make you run hotter.
When your car is cold give your top hose a squeeze so you know how it feels pressure wise, start your car and give it another squeeze every 30 seconds, if there is a pressure buildup before it gets warm it mkght mean a bad head gasket.
Another way as mentioned before is to look for bubbles.
Again, cold car, remove cap and fill/burp, start your car but DO NOT rev the motor. let it warm up at idle and keep an eye on the coolant, there may be a few bubbles from trapped air but those should pass soon, what you are looking for is bubbles that never stop.

Fernandoz3kGT · 11-12-2012, 10:02 PM

I used fresh water for the flush from the upper hose with no t-stat and waited to see clear water leave the bottom hose which i removed from rad and let it drain away. Did the same with the rad had water put in the top and watched in leave the bottom hose away, again it first came out brownish orange and stop until clear water made its way out. The car had this orange coolant in it when i got it. When i topped it off with the conventional green i started up the car cold with cap off and topped off as necessary letting a few bubbles appear and waited for the car to get warm top off and replace rad cap. Maybe the cooling system had been really dirty and with some rust and i didn't get all of it out??? I haven't cleaned the Reserve tank because its not easily removable and i cant see if its even dirty like previously said in the 99 model its location is kinda hidden. I have a new rad cap just not installed yet (too dark right now) and a new coolant temp sensor that will be installed tomorrow after hopefully another flush using a flush bottle from oreillys or something ? what do you recommend? Again i bought conventional 50/50 green coolant that will go in tomorrow.

Thanks for all the help!

Grandpa Poser · 11-12-2012, 10:14 PM

I have no preference as far as chemical flush agents are concerned, just follow directions, plan enough time so you dont leave any in you cooling systen. The reason I prefer letting a shop do it is that sometimes you can end up with a leak. If someone used stopleak or you have a thin wall thats about to go, per se.
One of your pictures showed the top of the rad, flat space with numbers, looks like OEM rad to me.

white1995vr4 · 11-12-2012, 10:27 PM

This same issue was happening to me and it turned out to be the cap. It was not holding the correct pressure. I just bought one at napa for 6 bucks, but make sure it is the correct pressure. Some of the aftermarket ones can be higher or lower pressure. My cap for my 1995 vr4 was 0.9bar but you might want to double check the one for a 1999. Like it was said before start with the cap and go from there. The cap is the cheapest part in the system.
Thanks,
Joe

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Fernandoz3kGT · 11-12-2012, 10:46 PM

Really? Never thought the cap itself could cause the issue, the one it has since i got the car looks ok i mean it seems to be fine no rust spots or wear on rubber. But this is the one i bought idk if i did good or bad but the guy at the store said it was good enough and has the security release.

Murray Caps & Stats 7913 - Safety Release Radiator Cap | O'Reilly Auto Parts

Fernandoz3kGT · 11-12-2012, 10:48 PM

And this is the sensor i got as well:

MasterPro Ignition 2-9338 - Coolant Temperature Sensor | O'Reilly Auto Parts

westcott · 11-13-2012, 10:59 AM

I am leaning toward a bad sensor. Your fans should come on much earlier than you reported and cycle fairly regularly.

I would change one thing at a time so you know what corrected the problem.

And yeah, the overflow bottle can be a pain but putting good coolant in a dirty system is counterproductive. You will be surprised how much rust can collect in the bottom of it.

I also suggest using nothing but distilled or RO water. Calcification is your engine\coolant systems worst enemy. 50/50 coolant may be convenient but you are paying a premium over mixing your own. Besides, 2 parts distilled water to 1 part glycol is the best ratio for maximum cooling while still maintaining proper rust and freeze protection.