first overheat problem EVER

[spectr019]

A week ago I installed all my winter supplied I had collected, of which included a Mishimoto radiator and a Megan catch-can. Installed everything and everything was good, but a fan blade was hitting my compressor outlet pipe, so I decided to get slime-lines. Ordered two Mishimoto 12" slime lines, and wired them for high speed only and to come on at the same time. I've watched them operate, so I know that I wired it correctly and that they come on.
Driving around today on city streets, my car started idling high...maybe 1200. Then next stop light, 1500. Next, 2000. My AFC is saying that I'm anywhere from 1.5 to 4% throttle. And suddenly, for the first time EVER, my temp gauge starts to rise (scariest moment of my life). I notice that when I'm in gear driving, however, the temp gauge returns to its normal position of temp.
So I get home and look around, hopefully something is simple staring me in the face. I notice that on my catch-can, one of the hoses is sealed shut. I routed the PCV on the back of the valve cover to the can, and from the can I have an in-line PCV valve going to the intake manifold. It was the piece of tubing from the intake manifold to the PCV valve in-line that was sucked shut. As soon as the car cools down I'm going to replace that hose with some vacuum hose.
Would that have been the problem? The fans were definetely blowing air (which was really hot by the way), and nothing else seemed to be out of place. I have idle surge once in awhile, but nothing like today, and with the temp gauge raising, I'm freaking out.
Sorry this took so long to explain. Thank you for any help.

Ben

 

[grnchevyz]

Sounds like you might have an air lock in your system. Take off the rad cap, start the car and see if you get air coming out...just keep refilling with coolant til it stays steady or you are satisfied there is no more air.

 

[spectr019]

seriously? Take OFF the radiator cap and THEN start the car? Won't coolant just blow out of there then? Certainly could be that there isn't enough in there, that just seems an odd way to measure the amount of coolant in the system.

Ben

 

[spectr019]

yeah for some reason I was reading what you were saying but thinking of taking the cap off WHILE the car is running. So you're talking about just like when doing a regular drain, flush, and refill of the radiator. Okay I'll give it a shot. Thanks.

Ben

 

[spectr019]

NEW SITUATION. Okay well now it's night time and a lot cooler than this afternoon. Went for an hour and a half drive. Finally after maybe an hour at a stop light the same situation started happening. The rpm will be higher at each stop, and my AFC will say that the throttle is around 2-4% open, and temp raises just past the waves, just past the half way point. I get to my garage and take a look. I can push on the throttle to close it and it works...? The rpms lower. The temp will still flucuate, however, from below half way to just above half way. The fans feel like they are blowing nothing but hot air. So it's my throttle though, it seems like it isn't closing all of the way. I've had that throttle body rebuilt by Steve Monroe and I installed it last Friday, a week ago. It COULDN"T be dirty enough to malfunction yet, could it?? But this kinda happened with my old throttle body as well, some surge. Could it be the cable? I wouldn't think so because the throttle spring shuts the plate closed itself. Could it be the BISS screw? I certainly can turn it in more to lower the rpms, but when it's idling regular it's fine right at 750-800. I'm very lost and confused with this

Ben

EDIT: P.S. the coolant levels are good, I double checked that, and I just drained and flushed and put new coolant in last week. The raising of the temp only has ever happened today after I put the slimelines in.

 

[spectr019]

Just ran into the garage and hooked up the data logger. The ecu is throwing me P0505, which is IAC valve system fault. I just installed a new one last fall, so it's been less than 6 months. Can they die that fast?? I think I have an extra floating around...I'll try it tomorrow when the engine cools down and see if that helps any.

Ben

 

[turboglenn]

Sounds like your cruise cable is too tight if it's getting to rev higher and higher the longer you drive. This is a common cause of idle surge and the process for adjusting it is documented on this site (just search for it )

As for the heating situation, i agree with the others to bleed the system and ensure there's no air pockets.

 

[stockfornow]

Well, you got two problems:

1: Your fans simply might not flow enough air. Try putting colder thermostat.
2: Your tb is sticking: Either when it was rebuild the nut on the shaft was tighetened a bit to much and needs to be loosened, or your throttle cable is too tight.

Edit: Sorry, when I looked at this, your post wasn't here, so I accidentally repeated your answer.

Also, you might want to try that stuff called something like water wetter...

 

[subie22]

You can try water wetter, but if you have a real problem that will not work, i know this since that was the first thing i tried. I would check make sure the tstat is working properly, if its from a autoparts store and not oem they are known to take a crap as soon as you put them in. Also like someone mentioned make sure you cars fans a fully making enough cfm's. Also you can up the rad cap pressure to 16psi. Just make sure all your hoses are in good condition, if not they will burst.

I had the same issues, i just took the rad out cleaned it very well, replaced the tstat, and used a 300zx rad cap. Its has not moved from the middle of the gauge. But could be a few things. Just do one thing at a time. Also to bleed coolant, it can take awhile to get it hot and get rid of all the air bubbles. It took me a half-hour out to just bleed it. But since then when it was being driven its perfect.

Also when you feel you got all the air bubbles out, take if for a decent drive. Your hoses should have some kind of pressure to them when you get home to check them. I knew i had an issue when i would feel the top and bottom hoses they were soft and warm. So i had no pressure.

I hoped this helped, this is what i did and it fixed my overheating issue.

 

[spectr019]

thank you everybody for your responses. I HAVE already tried loosening the adjustment bolt on the throttle, so I'll drive it and see if that made any difference. In regards to cleaning the radiator, it's a brand new piece so I wouldn't believe that it would need to be cleaned yet. I'll see what I can do about bleeding it and finding air pockets. I'll order a new radiator cap now, I know I've personally never replaced it (I've owned the car for half of its mileage life at least, but yeah it's gettin to be 13 years old). And if non of that works, I'll check the thermostat.
Nobody referred to the CEL I was getting about the IAV valve malfunction. Are the chances that that is in good shape and that's the only thing that the ECU can suggest? Again, I just replaced it late last fall.

Ben

EDIT: I have also never replaced the thermostat, so yes definetely could be something with that.
EDIT #2: Throttle cable definetely has some play if I wiggle it with a finger.
EDIT #3: Okay I just ordered a new rad cap rated for 1.3 bar, a new thermostat (OEM, not autozone or the like), along with a new set of radiator hoses. I noticed that when when I squeeze the top hose (when the car is cool) I can hear air escaping somewhere. Sounds like it's at the cap or the end of the hose, can't really tell.