1996 502 Impala SS Overheating Issues

[infomanSS]

My vote (even though the water pump has been rebuilt recently) is the water pump. If the fans are coming on properly and the engine isn't staying cool, then it is a flow issue. Flow could be thermostat not opening enough or the pump not working efficiently.

When you increased the RPM's and it started to cool, that seems to indicate the pump to me. Have you considered changing to electric water pump?

[Mr pogo]

Originally Posted by angelo

If we're all "bench racin'" here, i would ask others who have the 502....like BK or AREA51 who likely did the build.
Not saying you will get any help but no harm in asking....?

MY penny's say double check you are not running LEAN to rule it out as that is all i can think of that would make it run HOT if everything else is fine with your setup.

GL

-ALF out...

lol, why did I forget all about BK?

[502-SS]

I don't know if I have time to get the pictures tonight but I will take some pictures of the cooling line setup tomorrow after work and post them tomorrow night.

[udownwitk]

Originally Posted by Crime Scene 96

Im still stuck on the 502 part. Any pics?

I, too, saw 502 and immediately scrolled down to see pics... LOL, i skipped the story all together. HAHA!!

[Crime Scene 96]

Originally Posted by udownwitk

I, too, saw 502 and immediately scrolled down to see pics... LOL, i skipped the story all together. HAHA!!

LMFAO, when i saw the title of the thread this came to my mind (seriously):

Will Smith -Errr - YouTube

Will Smith -Errr - YouTube

[NADACOP]

More information please on your fuel management and fuel pump as well as what you are using to control the ?stock? fans please.

Hopefully you're aware that some big block water pumps are designed to run in certain rpm ranges. This one should be fine for the normal range that most big blocks see but if you wind it up around 7k you might be better off with a different pump.
You said you had it rebuilt by edelbrock, did they replace the impeller or just the O-ring?

Also, how did you plumb your cooling system? Did you plumb it like the stock LT1 system or like a normal big block system? The cap on the stock LT1 coolant recovery tank was rated to 15psi if I'm not mistaken. What is the one rated for on the Be Cool radiator?

You said it has always overheated. Was this engine actually used in a boat? Fresh water is more likely to pick up sand that will erode the pump impeller where salt water environments can leave salt deposits on the valves and seats causing other problems.

Most of your temps don't look wildly out of line though. Does it actually puke anti freeze and have you confirmed that you have a 195 degree thermostat?

Jim

[502-SS]

I understand the cooling fan issue and I thought that would be my next step but I called Be-Cool tech support and they don't seem to feel that it is a fan issue. I need to try and find out the CFM rating of the stock Impala fans because the guy at Be-Cool said that he would be glad to sell me a set of fans but he thought I should do more research before I spen the money on the fans.
I took the car for a ride last night which the outside temp was about 85 degrees. The route I took ranged from speeds of 30 to 45 mph and was about 4 miles around with hills flat areas and stop lights. The car seemed to be staying around 180 for the first 2 time around but on the third trip the temp would start to rise when I would come to a stop light and even when I took off and got up to 45 mph in high gear the temp kept on increasing.
The temp continued to rise to about 210 driving at a steady speed of 45 mph so I desided to drop down into second gear while maintaining the 45 mph. Once I was in second gear going 45 mph the rpm went to about 2750 and the temp came down to 180 almost instantly. I kept the car in second gear for about 1/2 mile still going between 40 and 45 and the temp held at 180. I came to a stop light and the temp started to rise and once the light changed I only let the car shift into second gear and drove home still at about 40 mph with a 180 temp.
I feel that the test I did last night tells me that it is not an air flow issue because I maintained a 40 to 45 mph (with electric fans) and when the rpms were low in high gear the car wanted to get hotter and when I down shifted into second gear raising the rpms the engine got cooler.
I now feel that it is a coolant flow issue like a thermostat not opening all the way or the Edelbrock water pump does not flow enough water to cool at lower rpms. I measured the crank pulley at a 7.750 diameter and the water pump pulley is about 5.625 diameter which matches the Z06 corvette a friend of mine has. I don;t know if this difference is diameters is correct for this motor but maybe I need a pump pulley diameter change.
I desided to change the thermostat today so I drained the fluid and un-bolted the housing and to my surprise there was no thermostat, someone has put a restrictor plate in place of the thermostat that has a 1 inch diameter hole in it so the motor has constant water flow. Why would someone do this and could this be my problem? I don't know the exact volume of water that can flow through that 1 inch hole compared to an actual thermostat but I would assume that the 1 inch hole in the plate would flow more water than the thermostat.
If it is not an air flow issue from the electric fans and it's not the thermostat the only thing that is left is that I need a higher flowing water pump or a pulley change. I don't want to make to much of a pulley change because I would think that I would start burning up bearings if I spin the pump to fast.

Reply to NADACOP
1) Fuel pump I am not sure but the car has a pressure gage that stays pretty steady at 48 psi. The car has a marine EFI unit bolted to the fender.

2) The overheating issues seem to be at lower rpms but if you get on the highway and really run it hard it will start to get warm but that is running hard and once you put that much heat into everything I guess it takes a while to cool it down.

3) Edelbrock did a complete rebuild (impeller, bearing, seal and new back cover).

4) I will try and describe the cooling line setup. Upper and Lower Hoses of course. The bypass fitting out of the pump goes to the intake just below the thermostat housing. The other fitting coming out of the water pump heads to the heater core but just under the stock impala reservoir tank there is a (T) fitting and off of the (T) it goes to the bottom of the reservoir tank and then the straight part of the (T) continues to the heater core. Then the other hose connected to the heater core goes to a port that is in the intake manifold which also has a (T) style fitting coming out of the intake and on the end of that (T) fitting there is a reducer fitting down to a 3/8 diameter hose which goes to the top port on the stock reservoir tank.

[502-SS]

I understand the cooling fan issue and I thought that would be my next step but I called Be-Cool tech support and they don't seem to feel that it is a fan issue. I need to try and find out the CFM rating of the stock Impala fans because the guy at Be-Cool said that he would be glad to sell me a set of fans but he thought I should do more research before I spen the money on the fans.
I took the car for a ride last night which the outside temp was about 85 degrees. The route I took ranged from speeds of 30 to 45 mph and was about 4 miles around with hills flat areas and stop lights. The car seemed to be staying around 180 for the first 2 time around but on the third trip the temp would start to rise when I would come to a stop light and even when I took off and got up to 45 mph in high gear the temp kept on increasing.
The temp continued to rise to about 210 driving at a steady speed of 45 mph so I desided to drop down into second gear while maintaining the 45 mph. Once I was in second gear going 45 mph the rpm went to about 2750 and the temp came down to 180 almost instantly. I kept the car in second gear for about 1/2 mile still going between 40 and 45 and the temp held at 180. I came to a stop light and the temp started to rise and once the light changed I only let the car shift into second gear and drove home still at about 40 mph with a 180 temp.
I feel that the test I did last night tells me that it is not an air flow issue because I maintained a 40 to 45 mph (with electric fans) and when the rpms were low in high gear the car wanted to get hotter and when I down shifted into second gear raising the rpms the engine got cooler.
I now feel that it is a coolant flow issue like a thermostat not opening all the way or the Edelbrock water pump does not flow enough water to cool at lower rpms. I measured the crank pulley at a 7.750 diameter and the water pump pulley is about 5.625 diameter which matches the Z06 corvette a friend of mine has. I don;t know if this difference is diameters is correct for this motor but maybe I need a pump pulley diameter change.
I desided to change the thermostat today so I drained the fluid and un-bolted the housing and to my surprise there was no thermostat, someone has put a restrictor plate in place of the thermostat that has a 1 inch diameter hole in it so the motor has constant water flow. Why would someone do this and could this be my problem? I don't know the exact volume of water that can flow through that 1 inch hole compared to an actual thermostat but I would assume that the 1 inch hole in the plate would flow more water than the thermostat.
If it is not an air flow issue from the electric fans and it's not the thermostat the only thing that is left is that I need a higher flowing water pump or a pulley change. I don't want to make to much of a pulley change because I would think that I would start burning up bearings if I spin the pump to fast.

Reply to NADACOP
1) Fuel pump I am not sure but the car has a pressure gage that stays pretty steady at 48 psi. The car has a marine EFI unit bolted to the fender.

2) The overheating issues seem to be at lower rpms but if you get on the highway and really run it hard it will start to get warm but that is running hard and once you put that much heat into everything I guess it takes a while to cool it down.

3) Edelbrock did a complete rebuild (impeller, bearing, seal and new back cover).

4) I will try and describe the cooling line setup. Upper and Lower Hoses of course. The bypass fitting out of the pump goes to the intake just below the thermostat housing. The other fitting coming out of the water pump heads to the heater core but just under the stock impala reservoir tank there is a (T) fitting and off of the (T) it goes to the bottom of the reservoir tank and then the straight part of the (T) continues to the heater core. Then the other hose connected to the heater core goes to a port that is in the intake manifold which also has a (T) style fitting coming out of the intake and on the end of that (T) fitting there is a reducer fitting down to a 3/8 diameter hose which goes to the top port on the stock reservoir tank.

5) The Be-Cool radiator does not have a cap the system just uses the stock reservoir tank with the 15 psi cap on it.

6) I really do not know if this motor was ever used in a boat because when I got the car this motor was already in it and from what I have been told the business that put this motor in the car is no longer in business after the economy took a dump.

I am just the unlucky sap that got a car that you can only drive in cool weather or run around is second gear from what I have figured out. I am sure there is a solution to this overheating issue but I need help figuring it out.

[Mr pogo]

Originally Posted by 502-SS

4) Then the other hose connected to the heater core goes to a port that is in the intake manifold which also has a (T) style fitting coming out of the intake and on the end of that (T) fitting there is a reducer fitting down to a 3/8 diameter hose which goes to the top port on the stock reservoir tank.

pictures are better dude.
not familiar with bb manifold plumbing but is the intake port at the cooling passages at the front of the intake manifold?
if so, disconnect and plug the lines temporarily and plug the intake manifold hole.
or pinch off the hoses that goes from the intake to the heater core and coolant tank.
one or the other, want to block flow from intake to heater core and tank.
then take it for a test drive and see if it overheats.
if it doesnt overheat then, I know what the issue is.

[502-SS]

Here are some pictures and as you can see I have it taken apart currently in order to get to the thermostat bolts where I found the restrictor disc with the 1 inch hole in it.