Overheating problem on 71 pontiac lemans sport 350

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Btc89

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I am having a problem with overheating in my car. I have flushed the block, new 160 degree thermostat, redone radiator, new cap, new overflow bottle, new hoses and new autometer water temp gauge. I did a 50/50 mix for the antifreeze and I did the fill it up then leave cap off until the thermostat kicks in then fill it all the way back up and put the cap on it. Well the problem is that when I do that and wait for the thermostat to kick in all the antifreeze does is splash out of the radiator and so I fill the radiator back up as fast as I can and put the cap back on it and then I looked at my gauge and it's saying 180 on the degrees then about 5 mins later it will start to overheat again. So I am running out of options. If anybody could help that would be awesome. Thanks!
 
Does the new thermostat open? ( cheap or name brand are known to fail, even new)

Water pump's age?

Trapped air/steam pockets or are water jackets full of crap? Blown head gasket?

Doug in P.R.:cool:
 
Water pump is fine, I believe my thermostat is working, I don't know if I have any blockage. There was some stuff in the block but I got it out. I notice that my radiator feels hot but my cap doesn't.
 
with the engine off and cold, assuming you have a clutch fan, how many times does the fan rotate if you push it by hand?
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I flushed my coolant system several times before I got all the brown crud out. Also, there is an issue with the divider plate behind the water pump. Many are not gapped correctly causing insufficient flow through the pump. The 2 bottom pics in this link show the before and after.
http://www.wallaceracing.com/water-pump-mods.php
 
Icefan71 said:
I flushed my coolant system several times before I got all the brown crud out. Also, there is an issue with the divider plate behind the water pump. Many are not gapped correctly causing insufficient flow through the pump. The 2 bottom pics in this link show the before and after.
http://www.wallaceracing.com/water-pump-mods.php
Click to expand...

Did you flush it with the block drain plugs out?

I 'm asking because I had a block once that was full all the the way over the top of the block drains and below the freeze plugs with brown crap . It was in there so packed in I had to take the heads off and use a long screwdriver down the waterjackets to get it all out.

Did you try radiator cool in the bottle? It does work, lowers you temps up to 20*.

Doug in P.R.:cool:
 
92 Sunbird LE said:
Did you flush it with the block drain plugs out?

I 'm asking because I had a block once that was full all the the way over the top of the block drains and below the freeze plugs with brown crap . It was in there so packed in I had to take the heads off and use a long screwdriver down the waterjackets to get it all out.

Did you try radiator cool in the bottle? It does work, lowers you temps up to 20*.

Doug in P.R.:cool:
Click to expand...
Haha yes I flushed it 3 times before I realized I should remove the threaded plugs. After I removed them, thats when I got all the crap out. I didn't have any hard stuff, though.
 
When I spin the fan clutch by have it doesn't spin very much. I bought a high performance thermostat it opens up at 160 but my car car is running at 190 right now.
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what PSI is the new radiator cap, 16? Are you using an overflow bottle or a coolant recovery bottle? A coolant recovery bottle uses a radiator cap with a rubber ring around the inside outer circumference. If you are using a coolant recovery bottle fill the radiator cold and add coolant to the bottle to the cold line. You could remove the thermostat and test it in a pan of hot water that you then bring to a boil to make sure it opens.
 
I replaced the water pump its a aluminum type, I installed a new high flow 160 thermostat, got my radiator cleaned out, new heavy duty fan clutch and 50/50 mix on the antifreeze and it slowly goes to 205 temp on the guage. Is this okay? I would like it cooler.
 
I am using a overflow bottle with a plastic cap.
 
1. do you have a full factory fan shroud installed?
2. There is no chance you installed the fan backwards, should say I believe "Front" on one side if it is a factory fan.
3. Are you using a 16 PSI cap with a rubber sealing ring around the outter diameter of the cap? Notice the ring around the top of the cap in this link. http://www.autopartsnetwork.com/radiator-cap-gates/avfCa4Lvx
4. Does the hose going to the bottle connect to the bottom of the bottle? If it connects to the top is there an internal hose going to the bottom?
5. What is the intial timing set for? retarded timing causes the engine to run hotter
6. Does the vacuum line going to the distributor have vacuum at idle or only when the engine speed increases above idle? Again having vacuum at idle advances the timing causing the engine to run cooler.
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The type of impeller on the "new" water pump is important, Pontiac originally used 2 or 3 different large cast impellers on the stock water pumps, most modern rebuilt water pumps us a generic stamped impeller that does not move the same volume of fluid the originals did. Pontiac V-8's also have a removable backing plate that goes behind the water pump, the clearance between this plate and the impeller can cause a lot of overheating issues if the clearance is to large. Also there are 2 transfer tubes (on 69 and later engines) that have seals on the front side of them, if the seals are hard they bypass fluid around the pump, again causing odd cooling issues

Here is a Link to a very long discussion on Pontiac V-8 over heating issues. Remember that the cooling system changed in 1969 and later Cars.

http://forums.performanceyears.com/forums/showthread.php?t=411256
 
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