I have a '89 Camaro RS with a new engine (355) converted to carb from EFI. For some reason that I haven't been able to figure out it constantly overheats since the new engine was put in. I have good water flow so I know the pump (which is new) is working. The radiator is a little dirty but still flows very well. Everything seems to be pointing at the thermostat (which is new) and replaced a new one already in the car.

It's been a long time since I built an engine and was wondering if the head gaskets could be put on upside down and cause water flow problems or am I over looking something else I haven't tried?

 

You did not mention the condition of the fan. The fan is probably the most common culprit in overheating issues. Run the car an note when/if the fan kicks on and get back to us. If its an electric fan, then removing your ECM will kill fan function. If its a manual fan, check for clutch operation.

 

Sorry, electric fan always on. With connect to a switch / sensor as soon as I figure out the problem.

I'm currently checking to see if the timing is a factor.

 

Does it overheat going down the road? Is the lower air dam still on the car? Camaro/Firebirds will always overheat if this lower air damn is missing, since it is the only way they can get fresh air up to the radiator.

Don't know about this one just something to put out there, if you go from V-Belt to Serpintine since you converted to efi and you used your old pump it may be spinning backwards??? Don't know about that for sure.

Do you have a good thermostat installed? Water in the radiator doesn't flow when it's cold does it?

Are running without a stat, the engine can overheat since the pump may push the water through the radiator faster then what the radiator was mean to handle to cool properly.

 

First time we drove it home it over heated, hasn't been driven since.

Has new serpintine belt.

Second new thermostat.

Took the stat out to see what would happen. It still over heated but a slightly slower rate.

I checked the timing and it was 16 deg. BTDC - I set it to 10 deg and it seems to be working. I'll keep checking and update later.

Thanks for all the replies.

 

For EFI timing I think it's supposed to be set at 6 degrees, computer will do the rest unless you have a custom tune.

You should have a lower air dam attached to the bottom of the radiator support if it's not there, go to the junk yard and get one it is the only way this car will cool going down the road. Here is what the piece looks like and hangs down from the radiator support.
http://www.hawksthirdgenparts.com/inc/sdetail/8423


On the serpintine it was more of a question to weather or not you used the V-belt water pump or not. If you did hopefully someone can give a definate to weather the water pump is spinning backwards.

 

You dont "have" to have the lower air dam providing you have an updated cooling system which mainly consists of a much larger radiator. My air dam kept triggering the finish line beams casuing me to break out when I needed to hit the brakes at the finish line...beams would catch air dam and show me getting to finish line quicker than I actually was since front tires are how muany inchs back from air dam??

ANYWAYS, LOL, if you just used a cheap auto store brand replacment stat, it's entirely possible your running into a batch of crappy ones....Ive never had good luck with anything other than OEM stats, I personally went through 4 stats in a row yrs ago within a week until I got one that worked properly...heard this story quite a few times from others and have since gone to the dealer fo replacements since. In fact I was in a bind with my plow truck last month with it overheating, did a new stat and it still overheated, changed clutch on fam, still overheated. next day when ford was open got an oem stat and it worked like a champ.

Might be worth your time to have system flushed if it's never been done, does'nt take much for the tubes to corrode up and hinder flow and if the shop is nice they'll keep the pan with crude to feast your eyes' on. Other than that, double check to make sure timing is correct as that in itself will cause issues. Also if this is a new motor you may just have a very stubborn air lock...been there done that too and since addition of electric water pump that's never been an issue, but sometimes they can be a real major PITA!! new empty motors have all kinds of knooks and cranny's to hid air pockets.