I just swaped out the 305 in my '83 camaro for a 350. I put a 180 degree thermostat in it and the car runs a 240 degrees. It warms up to 220 and then after you drive about 10 miles it jumps to 240. But it never goes above 240. And the strange thing is that the car stays cooler when its idling and warmer when its being driven. The fan is working. I know the thermostat is opening and closing and it is the second one I put in there. It has a 195 degree in it now. It is the original radiator in the car and is made for the 305, but I looked up a radiator for a 350 (only it was for an '87 since the '83 didnt come with a 350) and the '87 350 and 305 radiator are the same. Any help would be appreciated.

 

well you might to run dual electric fans instead of just one..

is your air dam in good shape?

what type of coolant mixture are you running?

 

the air dam is good and I am running 50/50. I didnt think with running a 300 hp 350 I would need dual electrical fans. Could I need a better flowing radiator.

 

Do any of the other guages drop when idling, like gas level and voltage?

 

I've always run more water then coolant, like a 60/40 or 70/30 mix. Water will pull more heat then coolant will. If your waterpump and radiator are in good shape, I wouldn't worry about them being able to handle a 350. I'm running over 300hp with my 350 and stock 305 waterpump and rad. and single fan setup and I'll run 180 all day long with a 180 stat. What did you do with your induction? Are you sure you're not running lean in the mid to top range cause that will cause more heat too.

 

The only thing I can think of is that the timing might be to advanced. But will that cause me to run as much as 240 degrees? I do not get any other gauge drops that I have noticed. Just curious, but why would that matter? But if the timing was advanced to far I think I would be getting detonation. How car I tell if the radiator is bad? It get pretty hot when the car runs for a while. The upper radiator hose gets hot so I know the thermostat is working. The only temp wire that is hooked up is the one that screws into the pass side head. Are there any others? Could there be another one that needs to be hooked up to maybe get a more accurate reading? Thanks for the help.

 

If the other guages were also dropping, it could have been a voltage drop whilst idling that caused the guages to drop, but as they are steady it does seem the engine is getting too warm when moving along.

Did you check for trash on the outside of the radiator?

Did you change the inlet manifold over? If so did you blank the front or rear cooling outlets in the heads? Most Camaro V8 engines need the rear outlet blanking, if it is not blanked, or worse the front is blanked, it overheats the heads.

The other place to put a sensor - apart from the other head, is below the thermostat housing, if it has been tapped to accept one there. That is the best place for the second sensor, becasue it lets you know the coolant temperature going to the thermostat, which can be different to the coolant in the heads.

It does sound like either the blanking problem or maybe bugs or ruts in the cooling passages. Did the engine get flushed before use, was it standing around a while open to the elements?

 

The radiator looks good. No trash on the fins. I did not use any blanks. Not even on the rear. It is an edelbrock performer manifold if that helps any. The old thermostat waterneck had a sensor on it but I put on an aftermarket waterneck. You can tell the car is running to hot so even if the guage is a little off it still is way to hot. Would not having the back spacer make it run hotter? It sat covered in my garage for about a month on an engine stand. It was very well protected. I have all new radiator hoses, radiator cap, waterpump. Water is flowing through the radiator. Maybe I need to change the coolant mixture to more water.

 

The problem sounds very much like due to the missing blanks. The coolant needs to flow from the pump, back along the block, then up into the heads, then forwards to the outlet at the front of the heads. If the blanks are not put in at the rear, coolant goes directly to the manifold, instead of along the head.

With the water going straight into the manifold, the flow almost stops in the heads. The head does not get sufficient cooling, and the thermostat does not get to the right temperature, until the engine is actually much hotter than the thermostat should open.

The heads can fit on either side of the engine, so they need coolant each end to make them fit either side.

A good gasket set from NAPA explains this too. I don't know if the competition manifolds can take the coolant at the rear, but the effect you are getting sounds just like what you'd expect with no blanks in place.

I use pure anti freeze and get cooling OK. I don't understand the water being better theory.

 

Actually, 100% Antifreeze would cool the car down. the only reason you dont use 100% antifreeze is due to it cools better so it will not let your car heat up.
If you only drive your car in summer take the thermostat out it will take alot longer to heat up..Try getting a lower air dam, yours may look good but i could be worn. Im trying to get some sort of scoop for the radiator to cool way! better. I just need to find the right stuff

 

Antifreeze does no cool as well as water, it only prevents corrosion and lowers the freezing point and raises the boiling point of your coolant. If you have only antifreeze your car will probably overheat.

Have you replaced the coolant temp guage sender? Sorry if I missed it.

 

I don't mean to flame here but that is total crap. I'm not sure where or who you are getting your info from,but I would suggest abondoning it now before you get even more miscondeptions. No offense.

 

Yup Yup. What is the condition of the lower radiator hose??

 

Well...It reall doesnt matter now. I went to start the car yesterday and the engine siezed up. I cant even turn it buy hand. What a waste of about $2500 and about a thousand hoursof hard work. Talk about a deep sinking feeling. I guess thats what to expect when you build an engine yourself for the first time. I guess I am going to have to pull it out and start over, so I guess it would be a good time to insert the blanks. I really appreciate your guys help.

 

Oi that sucks. Sorry to hear about it. I can't imagine what I'd do if that happens to me. Give up, most likely. hehe. Keep at it, you'll get there eventually.

BTW, 100% antifreeze is murder for the engine! It's also more viscous, which means more work for your water pump. Although, I hear there's a new antifreeze coming out that doesn't need water, something called NPG+. Anyone tried this stuff?

 

Before you give up, remember that the engine is not necessarily a wite off, also it may only be one cylinder or a valve that has stuck. You need to pull the heads and look at the bores, to see if they are damaged.

There are plenty of other things that would prevent the engine turning over. Take off the belts and see if it will turn over. It doesn't take much to make it impossible to turn.

Also if the engine was running, you shut it down and then it wouldn't start, or if it locked up shortly after starting, that does not sound like a sieze up. Did it stop dead when you switched off the ignition last time, or did it seem normal.

It seems very unlikely that it would sieze up if it had coolant in the system and was not boiling over.

There is only one way to learn about cars, and thats to work on them and that is guaranteed to lead to many screw ups and disapointments. Or you could take the car to a garage and pay lots and lots, for very little.

 

NPG... I heard you canrt use water with that or you get some bad *** repercussions. Dunno.. dont dick with it. Anyway... I had the same problem with my t/a... and ya know the problem when I got it to then engine shop? 2 blown rings and a cracked piston. I had no signs of it that i knew of. Somebody tried playing with the engine before I got it (seen that from taking it out to take to the shop)

Anyway, I was told it was because it was severly beaten before me. heh. anyway, Id check that out. As for that... I kept my heads... and went 350 block. Im doing fine now and isnt runnin over 180. 11:1 compression and even when romped on doesnt go a degree above. Id look into that if I were you.

I had the same problem where it actually gets hotter when you drive. I guess more stress when you have a piston cracked inside your walls.



Just my experience... hope it helps
~Cory