sbc running hot what to do????

ok here is our problem.... sbc 350 .30 over 10 and a half to one compression its a 99 block with vortech heads new water pump 165 degree thermostat tried a 185 degree first 64 pontiac lemans with original 3 core radiator was a 6 cyl car with air... its running at around 230 degrees and got up to 250 earlier when i started runnin it alittle hard.... we are wanting to drive it to the hamb drags but cant get this cooling problem fingered out.... and we also tried some of that stuff that is suposed to keep it 40 degrees cooler and it didnt do a bit of good..... by the way the motor has less than 3 thousand miles on it.... and we have a aftermarket electric fan on it....

 

I think either the radiator is too small or not flowing , or the thermostat is too low of a temp. If its running hot when your driving there could be a coolant flow issue. Check the hoses so they are not colapsing, make sure its bled out so you dont have any air pockets. Is it running lean? Check some of the previous posts on this topic, there has been a lot of overheating issues lately, might give you some ideas to check . Good luck.

 

Man heating problems ****!!!

Ignition Timing?
To Lean? what type of carb?
Air flow Air flow? does it heat while driving or at idle?
has this motor always ran warm, you said it has 3000 miles on it?
those 3 core radiators have a really small tank, is the radiator plugged full of rust?


Start with the basics I guess, hope ya get it figured out

 

If the faster you go the hotter it gets check your lower radiator hose it should be firm or with a wire coil in it. If not your pump might be ****ing the lower radiator hose and it is colapsing limiting flow.

 

edelbrock carb. and its not running lean at all... havent had it on a timing light gonna do that tomorrow just been doing it by ear.... what pressure cap should we be running???

 

15 lb

 

You said it's a 99 block with vortec heads. That's what I have. The water pump for that motor turns opposite direction as early chevy pumps due to the Serpentine drive. Did you put a v-belt and traditional pullys on a late model pump? If it turns backwards, you're hosed.

 

still has the serpentine set up on it.... maybe a old style water pump??? how would i tell???

 

but also the car it was in before was a 89 GTA trans am and we never had a cooling problem.....

 

I think poor coolent flow or poor air flow is your problem.

Old radiators tend to restrict coolent flow as they build up with crud inside.

Is your electric fan a pusher or a puller? The puller fans seem to be more effecent. Also, is the core where the air flows through clean? Its amazing how much **** builds up in there. And lastly, can the air get out of the engine campartment? Before the cooler outside air can go through the rad, the old hot air must be able to get out from under the hood. Big motors in small engine compartments with tube headers tend to close up the air flow exit paths.
Gene

 

i would say the radiator is clogged...im not a machanic but i have had my share of problems with overheating..lol..the faster you go the hotter it gets..its the radiator is not flowing...try this when is at its hottest run your hand around the radiator and check for cooler spots around the tanks..if its cooler than the other sides its not flowing

 

Just so I'm clear, You have a 99 Vortec motor with the serpentine drive intact, previously run in an '80 GTA without issue? If so, It's not likely that you have the wrong pump, but that doesn't mean the pump is up to snuff. You also said you have an electric fan. Do you have a shroud? If not, the fan can only pull air through the core that it covers, and at a lower efficiency at that. Increased road speed should help cooling. If not, I'm with the previous opinions that you have a faulty core, thermostat, pump impeller or hoses. I would start with a new stat. If the one you have has gotten hot even once, you can't trust it. Water pumps are cheap, install a new one and you get 2 years of confidence. Might as well do the hoses while it's off. By the time you are done, you will have replaced the coolant and seen how much trash was in it. If bad, take the core to the shop and get it cleaned out. After that, you're looking at motor questions.

 

What ignition you running?

 

I would check the thermostat first, go to an 185 and make sure it's in the correct way (sounds stupid, but easy to do) then the hoses. Then waterpump ...could be running in oppsosite direction. There might also be blockage in the radiator froman over-abundance of silicone used around the coolent p***ages or if it hasn't been cleaned in a while. If the other stuff doens't work, I'd take it to the local radiator shop and get it checked/cored and maybe add another row of fins. Hope it all works out for ya.

 

All advice is good so far... I'd say dump the radiator and pump just to be on the safe side. It's gonna run you under 200 bucks and will buy you alot of ***urance..

ALSO - put a timing light on it immediately. If you timing is a few degrees to advanced you will run hot. This can make a big difference. If you don't have a light back the timing off untill it starts running ****ty and then bring it up untill it just starts to come back together. You can do this for testing purposes but make sure you get a light on it.

Water wetter does help but is not a cure all. I've found 30% antifreeze 70% water wetter really helps in my car... But first you've got to get your coolling system reasonably efficient or it's not going to help.

I would kinda rule out the fan if you are running electric since it will have a built in shroud. If your not running cooler while your moving it's probably not a fan issue.

 

I can't remember my old 64 Goat was cause I have CRS, but I would make sure that direction of the flow through the 64 Pontiac radiator you have is correct and is the same direction and flow of the original chevy radiator. If the previous radiator worked why not use the same thing also I doubt that the 64 radiator is big enough or actually efficient enough. Just my guess, and like others have said make sure you have a shroud. Another point you might check out is are you using a mechanical sensor or electric and are they consistant with the gauges you are using, i.e is it really getting hot or is the sensor and gauge mismatched. Are you running an automatic transmission through the same radiator? do you have a heat gauge on the ******?

 

This is my opinion also, I would buy a new pump for the bracket setup and a new stat, $40 well spent...........

 

The old goat has a shroud and it is completely sealed around the whole radiator.....brought the timing light home and gonna try that in a bit......The motor ran perfect in the GTA without any cooling problems at all....The radiator doesnt have the coolant p***ages for the ****** it is on a seperate cooler.....we have drained the radiator about 2 times in 5 days and everytime the fluid still looked brand new.......last night while driving it on the highway the air was about 65 degrees and it still got hot........Got to figure this out!!!!!!!!!!!!!!!!!!!!1

 

3 thousand before what the rebuild or after it? Was the block boiled to clean it? IE: hot tanked ? I hate to say it but many a hot engine problem is from old crusty blocks that werent hot tanked and still have **** in em and just wont cool. Also an overbore adds to the problem.
Dave

 

Are those aluminum heads? Even with aluminum heads you gotta have your motor tuned right to run cheap gas at 10.5 cr without pinging ( you can't hear all detonation) Preignition will cause overheating. Try hi oct. fuel.

Is the sending unit too damn close to block hugger headers to be accurate??? I'm just throwing out ideas, not claiming to be a mechanic.

 

The motor was rebuilt 3000 miles ago.....It ran in the Gta for the first 3000 then we put it in the old goat.......never had a problem in the Gta........now we are having problems.......PLEASE HELP

 

The temp unit is in the intake where the heater hose used to run off of it..........and last night we drove it about 25 min.....and it ran about 230 most of the time but it slowly kept climbing but real slow.....then got into it a little bit and it boiled over and the gauge read 250.........Does that help

 

As said,id check the water pump and fan seen a guy put a serpentine set up on wit an old clockwise water pump and fan,then he put the new ccw waterpump on but didnt change the fan at that time,still ran hot,then he figured it out to get a ccw fan.problem solved.

 

well we never changed the pump from the GTA to the goat and it never had a problem in there.......so I dont know we just hooked the vacuum advance to the manifold instead of the carb and we set the timing../.... and getting ready to try a 180 stat instead of the 160..........Anything else to try while im at it??????

 

Drill a hole small hole in the outer rim of the stat before putting in will help purge air out

 

did you check around the radiator for cooler spots to see if its flowing through out the tanks?if its cooler on one side than the other you can tell the differance

 

most likely your radiator. that's the only thing different sounds like. newer motors run hotter, so you probably need a new rad.

 

I just had the same problem with my chevy truck.I am here to tell you it' your radiatior

 

This is going to sound like a stupid question but:

are you sure that the fan is moving air the right direction??? - Stick a rag infront of the radiator and see if it gets ****ed into the radiator. Even if you have a ****py shroud it should pull some air. (my fan was about 2" away with no shroud - stock style pump driven fan - and it would still pull air through the radiator.

I know it sounds really dumb but I just had a guy with a '35 ford with a build flatty and he had the two electric fans hooked up backwards - they were pushing air out the grille - useless.

double check you got the hooked up right - some will run as a pusher or a puller depending on how you wire them.

 

well we got it down to a constant 230 drilled a hole in a 180 degree thermostat i was a tooth off on timing and its runnin real good.... See yall at the drags!!!!!