I have a boosted b16a2, currently on a base tune of only 5lbs, but i have a problem. The car will sit at an idle and not overheat all day long but if i drive it for more than maybe 10 minutes it starts overheating quickly. It has fluid, there is no air in the coolant, the thermostat is good, the fan is blowing the right way. I cant figure it out any suggestions ??

 

Your airflow is probably obstructed or inefficient.

 

No ive checked all that as well, thought maybe a coolant line was collapsing so i replaced them and thats not the problem as well im stumped i have no idea what else it could be ??

 

Sure your fan is blowing in the right direction?

 

Excuse me. How do you check that when the car is in motion?

Is your rad and fan stock?

 

do you have a wide band? if so whats the afr? under load the car might be leaning out and getting hot

 

Have you checked the water pump? 94

 

Yeah my fan is blowing in the right direction, i believe its a stock fan with an aftermarket radiator not sure on the brand probably ebay. No i dont have a wideband but when the car gets into boost it black smokes a little bit so im assuming its running rich. And by the looks of the water pump it was just replaced looks brand new.

 

"by the looks of it"? How can you tell? Why no wideband? "Assuming it's running rich"? How do you know that without a wideband?

You seem dead set on shooting down anything we suggest.

 

No im taking all suggestions at this point, and the label on the radiator is so faded i can hardly make out what it says looks like c&r racing ?, ive had the car for like 5 days didnt come with a wideband and am waiting on my paycheck to order one, and i always thought if a car is black smoking under a load usually means it running rich.

 

I would stop driving it. What did the previous owner say about the smoking and overheating?

 

He didnt mention either one i let the car idle and get to running temperature before test driving is but i guess i didnt drive it long enough for it to start overheating. My mistake.

 

If it was the water pump wouldnt it overheat at an idle as well ?

 

Does it overheat while driving down the highway? What about driving in town?

 

Headgasket? IS your overflow filling up?

 

Havent had it one the highway yet just around town.

 

Yeah overflow is filling up

 

Headlift? Crappy rad? Any mixing of the oil? Do a compression test if you can.

 

Is your overflow, OVERfilling? If so it could be as bad as a HG or as simple as a radiator cap!

 

After you drive it for a few minutes, does the radiator get hot (not warm....HOT!!!)?

Start the car (cold) with the radiator cap off, let it get up to normal temps and can you see the coolant "moving"?

 

no its not overfilling but i have heard people say it could be a radiator cap, how many lbs should a cap hold

 

Yeah the radiator gets pretty damn hot, and yeah i can see the coolant moving

 

Temp sensor?

I believe the stock cap is like .9 bar (1 bar = 14.7psi). In my experience the cap increases pressure to increase the boiling point and does little to actually help the "cooling".

 

i was always told. idling overheat=fan, fast moving overheating=bad radiator. assuming the rest of the cooling system is ok

 

that seems right i think, my boosted b18b/vtec also have overheating problems and i cant figure it out.
not to thread jack this but if i let me car idle without the fan on then it over heats, soon as i turn the fan on the temp goes to normal, when im driving with the fan on at a constant high speed like 70-80mph then my temp goes up, i have to let of the gas a little to drive at 65mph then it will be ok. Im thinking of either getting a new fan or new radiator but cant make up my mind which one to get first.

to the op, maybe try a slim fan that flows more cfm than the stock fan, see if that will help. and make sure to get a shroud for the fan too!