Getting hot
03-13-2011, 04:02 PM
#46
Chronic Tool Dropper
Lifetime Rennlist
Member
Lifetime Rennlist
Member
Turn the heater on with all the radiator bits reinstalled. This time, when you start the engine the first time, run the RPM's up to 1500. Keep the reservoir FULL. like right to the top FULL. Pull the vent hose from the top of the radiator itelf, and put it back on only when you start to see coolant come up from the nipple on the radiator. This burps all the air out of the radiator, the full reservoir means max push to get air pockets up and out, and the increased RPM's and heater open mean that coolant air bubbles will have an easy path to the reservoir. Monitor the temp gauge. When you hear/see the fans run, there's full circulation through the radiator.
03-15-2011, 12:32 AM
#49
Racer
Thread Starter
Scratch that last post!!
I was foolish and forgot that there was more than one jug of coolant that came out!
So I added the rest and no sudden over heating just gradual over heating like before.
Thanks to Dr. Bob I turned the heater on and bled the radiator and got another gallon of coolant in. I also noticed that the heater was cold even when the engine was at 200 deg f. I raised the rpm to 1500 and the heater got warm and the radiator started to just get warm and the car began slowly cooling down. It will continue doing this cycle. It also still over heats under load while driving.
There are no bubbles or exhaust smells coming from the reservoir ever and no coolant just disappears, so I seriously doubt it is a head gasket at this point.
I was foolish and forgot that there was more than one jug of coolant that came out!
So I added the rest and no sudden over heating just gradual over heating like before.Thanks to Dr. Bob I turned the heater on and bled the radiator and got another gallon of coolant in. I also noticed that the heater was cold even when the engine was at 200 deg f. I raised the rpm to 1500 and the heater got warm and the radiator started to just get warm and the car began slowly cooling down. It will continue doing this cycle. It also still over heats under load while driving.
There are no bubbles or exhaust smells coming from the reservoir ever and no coolant just disappears, so I seriously doubt it is a head gasket at this point.
03-15-2011, 12:35 AM
#50
Chris, saw you called. Give me a ring in the morning if you need to.
03-15-2011, 10:16 PM
#51
Racer
Thread Starter
I have removed the water pump now and it seems to be tight on the shaft when twisting the pulley and holding the impeller.
Given this and the information in post #49 what are everyones thoughts?
Thanks!
Given this and the information in post #49 what are everyones thoughts?
Thanks!
03-16-2011, 11:57 AM
#53
Racer
Thread Starter
It felt tight just like when I installed it. Could it really be slipping? Does anyone have any experience with a slipping pump?
If its not the pump Im really stumped. BTW there are no signs of the belt slipping.
If its not the pump Im really stumped. BTW there are no signs of the belt slipping.
03-16-2011, 12:24 PM
#54
Team Owner
how are you measuring the temperature of the running hot engine??
If your not using an IR gun then all bets are off.
OTOH if you are using it and your seeing temps over 220 then you definitely have hot running issues.
normal temps you should see are at the top rad hose about 185 to 195
return should be about 165 to 185.
to fill the cooing system remove the cap and fill it up ( the system holds just about 4 gallons if you only put in 2 or 3 then its not close to being full. )
Then turn on the heater to full hot, the run the engine with the cap off, till the fans come on.
Then go for a 5 mile drive with the heat ON, and the cap ON.
Then park it and let it cool off,
top up the system after the system cools,
if you have an old heater control valve replace it with a new part and a new short hose
If your not using an IR gun then all bets are off.
OTOH if you are using it and your seeing temps over 220 then you definitely have hot running issues.
normal temps you should see are at the top rad hose about 185 to 195
return should be about 165 to 185.
to fill the cooing system remove the cap and fill it up ( the system holds just about 4 gallons if you only put in 2 or 3 then its not close to being full. )
Then turn on the heater to full hot, the run the engine with the cap off, till the fans come on.
Then go for a 5 mile drive with the heat ON, and the cap ON.
Then park it and let it cool off,
top up the system after the system cools,
if you have an old heater control valve replace it with a new part and a new short hose
03-18-2011, 01:21 PM
#55
Racer
Thread Starter
Just replaced the water pump, which did not change anything. The heater still doesnt work and the car needs higher rpm's to cool at all. Also under load while driving at any speed it will overheat more quickly. It seems as though the higher rpm's are starting to have less effect now too as its hard to get the heater to change temps or the engine to cool now. BTW those who suggest to watch for the fans to kick on I have an '86 with a clutch fan (that works).
To summarize I have so far....
Replaced the thermostat and both front and rear seals with no change. I have also confirmed that the old one was good and the new one is good.
Replaced pressure cap with new 13lb cap which made no difference.
Replaced water pump with new laso pump with no change in cooling.
I have removed the radiator to check for gunk buildup, did not see anything at the inlet side and only a slight build up at the return, but thats not always telling. However a clogged radiator wouldnt have caused the heater to not work without higher rpm's.
What the hell I am stumped.
PS> The engine doesnt heat unevenly, as in the heads are the same temp as the thermostat housing and water pump. The upper radiator hose gets hot, last time I checked the lower did too but obviously not as hot, but the air being blown by the fan is just warm rather than HOT. So there is circulation to some degree. Where does the heater take coolant from?
To summarize I have so far....
Replaced the thermostat and both front and rear seals with no change. I have also confirmed that the old one was good and the new one is good.
Replaced pressure cap with new 13lb cap which made no difference.
Replaced water pump with new laso pump with no change in cooling.
I have removed the radiator to check for gunk buildup, did not see anything at the inlet side and only a slight build up at the return, but thats not always telling. However a clogged radiator wouldnt have caused the heater to not work without higher rpm's.
What the hell I am stumped.
PS> The engine doesnt heat unevenly, as in the heads are the same temp as the thermostat housing and water pump. The upper radiator hose gets hot, last time I checked the lower did too but obviously not as hot, but the air being blown by the fan is just warm rather than HOT. So there is circulation to some degree. Where does the heater take coolant from?
Last edited by Formula94lt1; 03-18-2011 at 01:42 PM.
03-18-2011, 05:37 PM
#56
Race Car
If you are not losing coolant, either you have air in the system and/or you have a physical blockage in some engine coolant passages (not the radiator). Also, when you replaced the water pump, what did the block look like that is directly opposite the water pump impeller? It should be perfectly smooth.
Dan
'91 928GT S/C
475hp/460lb.ft
Dan
'91 928GT S/C
475hp/460lb.ft
03-18-2011, 07:37 PM
#57
Racer
Thread Starter
Perfectly smooth.
What could be blocking a passage?
Coolant is properly filled and burped.
Head gasket?
Ive been meaning to get some one over to help make sure the car doesnt overheat in the process of me bubbling air through the test liquid to test for combustion leaks into the coolant. There is no bubbling or exhaust smell from the coolant tank which is apparently something you should notice if the gasket is bad enough to cause overheating.
What could be blocking a passage?
Coolant is properly filled and burped.
Head gasket?
Ive been meaning to get some one over to help make sure the car doesnt overheat in the process of me bubbling air through the test liquid to test for combustion leaks into the coolant. There is no bubbling or exhaust smell from the coolant tank which is apparently something you should notice if the gasket is bad enough to cause overheating.
03-18-2011, 07:47 PM
#58
Rennlist Member
did you put the t-stat in correctly.
just do my test. it will allow you to diagnos the problem quicky and easily!!
take the old T-stat. force open the shaft with a spacer (small electric motro spur gear works great) and replace. Now, your system is not dependant on the T-stat. lets see if you aregetting flow. out of the pump or out of the radiator. (see prior posts how)
this is not rocket science. you can do it. the surface doesnt have to be smooth. scots is all grounded down from a failure, and still works great. (block surface)
either your pump is still bad, or you have a tstat that is put in backwards or some major blockage in the system like a rag left in the block.
my test will determine this!
just do my test. it will allow you to diagnos the problem quicky and easily!!
take the old T-stat. force open the shaft with a spacer (small electric motro spur gear works great) and replace. Now, your system is not dependant on the T-stat. lets see if you aregetting flow. out of the pump or out of the radiator. (see prior posts how)
this is not rocket science. you can do it. the surface doesnt have to be smooth. scots is all grounded down from a failure, and still works great. (block surface)
either your pump is still bad, or you have a tstat that is put in backwards or some major blockage in the system like a rag left in the block.
my test will determine this!
Just replaced the water pump, which did not change anything. The heater still doesnt work and the car needs higher rpm's to cool at all. Also under load while driving at any speed it will overheat more quickly. It seems as though the higher rpm's are starting to have less effect now too as its hard to get the heater to change temps or the engine to cool now. BTW those who suggest to watch for the fans to kick on I have an '86 with a clutch fan (that works).
To summarize I have so far....
Replaced the thermostat and both front and rear seals with no change. I have also confirmed that the old one was good and the new one is good.
Replaced pressure cap with new 13lb cap which made no difference.
Replaced water pump with new laso pump with no change in cooling.
I have removed the radiator to check for gunk buildup, did not see anything at the inlet side and only a slight build up at the return, but thats not always telling. However a clogged radiator wouldnt have caused the heater to not work without higher rpm's.
What the hell I am stumped.
PS> The engine doesnt heat unevenly, as in the heads are the same temp as the thermostat housing and water pump. The upper radiator hose gets hot, last time I checked the lower did too but obviously not as hot, but the air being blown by the fan is just warm rather than HOT. So there is circulation to some degree. Where does the heater take coolant from?
To summarize I have so far....
Replaced the thermostat and both front and rear seals with no change. I have also confirmed that the old one was good and the new one is good.
Replaced pressure cap with new 13lb cap which made no difference.
Replaced water pump with new laso pump with no change in cooling.
I have removed the radiator to check for gunk buildup, did not see anything at the inlet side and only a slight build up at the return, but thats not always telling. However a clogged radiator wouldnt have caused the heater to not work without higher rpm's.
What the hell I am stumped.
PS> The engine doesnt heat unevenly, as in the heads are the same temp as the thermostat housing and water pump. The upper radiator hose gets hot, last time I checked the lower did too but obviously not as hot, but the air being blown by the fan is just warm rather than HOT. So there is circulation to some degree. Where does the heater take coolant from?
03-18-2011, 07:49 PM
#59
Rennlist Member
the test is simple for exhasut gas . you wont smell anything really, but the tester will sense the presence of exhasut gas. just before it warms up put the tester in the opening of the overflow. rev the engine a bit. it will turn the liquid color if you have a head gasket leak. BUT, if it is this bad, you would be pushing water out the over flow . so its probably fine.
03-18-2011, 08:13 PM
#60
Rennlist Member
Sounds like its time for a new radiator.
I was able to extend the life of mine with reverse flushing with a shop vac at the inlet and introducing dishwashing soap at the outlet. About 100 gallons of water.
Forced half a tube of 10,000 cp silicon into my working fan.
Now the needle runs to horizontal on the gauge, a big improvement.
I was able to extend the life of mine with reverse flushing with a shop vac at the inlet and introducing dishwashing soap at the outlet. About 100 gallons of water.
Forced half a tube of 10,000 cp silicon into my working fan.
Now the needle runs to horizontal on the gauge, a big improvement.