ok heres the deal. i swapped my 305 with a 350. the 350 has a lot of engine work done to it and is a very good engine. i got it in my car and ran fairly well but...it overheats at a high rpm. it has a new 180 thermostate. the radiator has no leaks. and it only had water in it but it had enough just so i dont go waiting coolant incase there was a leak. when its at idle around 700 rpm its fine and stays steady at 180degrees or so. but once i started to drive it or when i tried to seat the cam. it gradually started to over heat up to 220 and 240. i have no idea what could be causing this but my grandfather who helped me put the engine together thinks that its maybe running fine and is not overheating and that maybe the temp gauge is at fault. i think he thought that because then it was up to 240 degrees, the water didnt start boiling in the recovery tank when i shut it off when it should have if it was at this temp. does anyone have any idea what could be wrong? by the way it is an 88 z28 camaro...

 

well i have another question. i just talked to my grandfather and he said that he thinks he figured out why the camaro is over heating. well the grill is blocked off in the middle but has a passage way on both sides like all grills are on this model to my knowlege but anyways he says that there has to be something that routes the air from the sides of the grill to the middle where the fan is. he wont tell me what this part is but he says its a part that i have to order because its missing on my car. does anyone know what this part is what its called and how it works. i havent the slightest clue what hes talking about because i've never seen it...probably because its missing on my car. he says this explaines why the car stays fairly cool when its at idle in a dead stop but why you arnt getting enough air flow when driving or at a higher rpm. does anyone agree with him??? please help!!!

 

I would make sure its not running lean and the timing is set properly. With a scantool, you can watch the fuel trims (Block learn and Integrator) to see what its doing. If its running lean, you'll see it on the scantool.

Also, make sure the timing is correct, and make sure you disconnect the EST wire by the A/C box when you do this.

As far as airflow, you should have a small strip of plastic right below the condensor to direct air up to the condensor/radiator while driving. This is called an air defelector or air dam depending on who you talk to. I'm not sure what your grandfather is talking about, hopefully somebody with a Camaro can chime in here...

 

do you know or does anyone know of a link to a picture of an air dam cause i have no idea what it looks like since i evidently dont have one on my car according to my grandfather. but i want to see what it looks like just in case i really do have it and my grandfather just doesnt know that its already there. is it something you have to order from the dealership?

 

Here is a picture of a camaro air dam. Its just a plastic "wall" hanging down in front of the condensor to direct air (while moving) up into the condensor and radiator assembly. It only works while driving, if your overheating while not moving, something else is wrong.
https://www.thirdgen.org/techbb2/sho...ro+air+dam+pic


What water pump did you use for this?

 

You only need two things to keep an engine from overheating: coolant flow to cool the engine and airflow to cool the coolant. Your fans normally don't come on until ~225* or so... can you tell when they come on? Does the engine cool off when the fans come on?

To me, it sounds like a coolant flow problem, really. I can only speculate at the cause, but it could be a a failing water pump, a blockage somewhere in the lines or radiator, or your t-stat doesn't open fully for some reason.

The part your grandfather is referring to is the fan shroud. If your fans are far from your radiator, then it could cause a slight issue, but I doubt it would cause a big problem.

 

well i know that the coolant is flowing atleast somewhat cause we left the cap off once to make sure. and we have a rebuilt water pump and a new thermostate so i dont think that is the problem altho that doesnt mean that those things are ruled out.

and as far as the fan it has the original shroud and i had to wire the fan so it runs all the time once a switch is turned on so that wasnt the problem.

the car didnt over head when it was at idle and sitting there. it only overheated when i was driving it...which it over heated gradually and when i was in park and had the engine at 1700 rpm or so constant for about 10 min trying to seat the cam. i'm going to go to a bone yard i guess and try to get an air dam and put it on my car. i'll only have time to do this on tuesday so i'll put it on and drive it and see if it makes a difference. but we'll see. thinking about it, it may be the problem cause at idle the temp stayed at about 180 but once driving it could have used the air dam...

 

The reason I ask about the waterpump, is because pumps installed on engines with a Serpentine belt drive spin the opposite direction of those used on V-belt cars. So when you shop for waterpumps, you can't just ask for a SBC pump, you have to specify either the "year, make and model" or "serpentine accessory drive".

Have you looked to see if you do have an air dam? I'd hate for you to buy one only to find out you already had one when you go to install the new one.

 

well i got an air dam from a junk yard which was in decent condition and went up to my gf's house to put it on my car. i guess that was what i needed cause it stayed right about at 180 the whole time although once on the highway going home it got alittle hotter like around 200 but stayed steady but once i got off the highway it started to rise for some reason up to 220. once it went alittle past 220 i stopped so it could cool. once i started driving it again it stayed cooler than 180 so its weird...but anyway for the most part it stayed cool, and this was a good 63 mile trip none stop. i dont plan on driving this thing around like that everyday anyways. anywho, its cuts off when i'm at a stop light from time to time too cause the idle is so messed up. it goes up and down and when it gets too low it cuts off. well its here at my house now so i'm gonna fix these leaks i have so the only thing i really should need after that (hopefully) is to get it tuned. oh i dont know if this makes a difference but i was only running straight water in the cooling system on the way home just incase there was a coolant leak or something so i didnt have to waist money on more coolant.

 

Once you decide you don't have any leaks, get some coolant in there!

220° is considered normal. Fans don't kick on untill 225° (unless hotwired like yours).

Glad the air dam helped!