Hmmm! - Cooling issue
Discussion
As some will know I have got to the stage where I can start my LS7 and generally annoy the neighbours whilst 'testing' the idle, oil tem and pressure and water temp and the odd mandatory blip of tthe throttle for good measure!
Seriously though, yesterday was the first time I left the engine idling to see if and when the fan kicked in, after checking the wiring and testing employing the orange & black wires thoughtfully left in the dash collection for a switch, and yes, I could start the fans ok...however..
The water and oil tems climbed nicely, oil pressure maintained around 75-85, but after a bit I noticed the water temp climbing to beyond 90 with no sign of the fans kicking in, resulting in an increasing rough idle, so I switched off.
The water temp is measured at the heads, so I assume would be much higher than the radiator, which is a worry - also the oil temp at the final point, the bypass valve (to the oil radiator) was still closed as evidenced by a cool radiator and leading hoses.
A bit concerened that maybe the water thermostat switch is not really suitable? I have no idea at what temp it is supposed to open, but it may open too late considering the location in relation to the engine?
Thoughts please?
Cheers
keith
Seriously though, yesterday was the first time I left the engine idling to see if and when the fan kicked in, after checking the wiring and testing employing the orange & black wires thoughtfully left in the dash collection for a switch, and yes, I could start the fans ok...however..
The water and oil tems climbed nicely, oil pressure maintained around 75-85, but after a bit I noticed the water temp climbing to beyond 90 with no sign of the fans kicking in, resulting in an increasing rough idle, so I switched off.
The water temp is measured at the heads, so I assume would be much higher than the radiator, which is a worry - also the oil temp at the final point, the bypass valve (to the oil radiator) was still closed as evidenced by a cool radiator and leading hoses.
A bit concerened that maybe the water thermostat switch is not really suitable? I have no idea at what temp it is supposed to open, but it may open too late considering the location in relation to the engine?
Thoughts please?
Cheers
keith
Edited by V8 Vum on Monday 8th November 15:47
not sure what ECU you are using, but I can adjust the temp the fans are starting in the ECU software and I am measuring the water temp at the water pump for my dash display. The difference is quite significant (20 -30 degrees) and I had to increase the temp for fan kick in to 105 or 110 degrees (do not remember exactly) to avoid fans kicking in too early. If you radiator is cold then your thermostat has not opened yet or is defective, so in this case the fan switch in the front sees cold water nothing else. If you use the GM ECU there was this nice OBD software that would allow you to monitor all these signals coming from your engine.
I will have to check Spatz. The fans are controlled by the thermostat in the front top of the radiator as per std Ultima.
The temp I am measuring is degrees C so at 90 degrees it is nearly at boiling.
The rad was warm, but I suspect no-where near warm enough to kick the fan in.
It may be a bleeding problem as the rad is a long way from the engine.
Has anyone got a suggestion or method of removing trapped air in the system? ...or at least to check?
I remember years ago we used to use a rad cap with a long tube to a reservoir, but then the radiators do not have such a cap.
cheers
keith
The temp I am measuring is degrees C so at 90 degrees it is nearly at boiling.
The rad was warm, but I suspect no-where near warm enough to kick the fan in.
It may be a bleeding problem as the rad is a long way from the engine.
Has anyone got a suggestion or method of removing trapped air in the system? ...or at least to check?
I remember years ago we used to use a rad cap with a long tube to a reservoir, but then the radiators do not have such a cap.
cheers
keith
The rad is fitted with a bleed tube back to the swirl pot. Provided this tube has been fitted correctly the rad will bleed itself without any intervention of the user.
It may be that your water pump is not moving enough water at tickover. In its normal application it only has to move the water a few inches from the rad and back whereas we have many feet of water to move. This is the reason some have gone for electric pumps.
Steve
It may be that your water pump is not moving enough water at tickover. In its normal application it only has to move the water a few inches from the rad and back whereas we have many feet of water to move. This is the reason some have gone for electric pumps.
Steve
Like http://www.demon-tweeks.co.uk/Motorsport/Cooling_S...
But where do you put it? Not much room!
Cheers
But where do you put it? Not much room!
Cheers
I have small block but the problem was the same for me. water pump was unable to circulate enough water at idle to cool engine or to get fans to kick in until water temp at engine was 110deg C plus ( not boiling coz of pressure in system). So I replaced belt driven pump with an electric one which is speed controlled by the water temp as it leaves engine. It also controls the fans which kick in when temp is 3 deg above set point. Engine remains cool at idle. It works perfectly. It also circulates water after engine switch off. Pump is CSR bought on ebay. I believe that they also make to fit LS engines
The LS water pump is more than capable of pumping the water around the Ultima cooling system!!!
Firstly have you got your H pipe connected into the system?
The LS uses a reverse water flow setup ie the water circulates around the heater system before opening the stat(86 degrees opening temp), if you have not got it flowing correctly this will cause you problems.
The Ultima temp sensor is not very accurate and to be honest i would use your ECM to switch the fans( connect it to the fans relay), the ecm will not switch the fans on until 98 degrees (can be changed). The LS is designed to run "hot" and needs to see temperatures in the 90's to run at its best.
Firstly have you got your H pipe connected into the system?
The LS uses a reverse water flow setup ie the water circulates around the heater system before opening the stat(86 degrees opening temp), if you have not got it flowing correctly this will cause you problems.
The Ultima temp sensor is not very accurate and to be honest i would use your ECM to switch the fans( connect it to the fans relay), the ecm will not switch the fans on until 98 degrees (can be changed). The LS is designed to run "hot" and needs to see temperatures in the 90's to run at its best.
standard thermostat fitted to a LS7 is in the 90s Centigrade. So based on your temp gauge it should not be open yet. The factory gauge which I use on the dash is 4 degrees over what my Motec reads at the same head location I would bet on the Motec. So you may have only seen 86 degrees. As far as the idle quality goes these motors are mapped to run at least at 94 degrees. What I am saying there is that the engine getting to a mere 90 has nothing to do with a unstable idle. Hope that helps. Lee
Thanks Guys,
Kyle, yes I have the heater H pipe sorted, I think something else is going on then...Just a bit surprised when the idle got so rough at that temp, and trying to pick the revs up became more and more difficult the hotter it got.
Maybe I was a bit previous... I will have to reconnect the OBDII plug which I am relocating in the cab, and then 'see' what my App tells me. Its probable that its picked up some error-codes through me messing around - need to check all the sensors are in place, and I will reset the system I think and try again.
On the water-fill exercise, whats the best method of ensuring all air is out of the system?
cheers
Kyle, yes I have the heater H pipe sorted, I think something else is going on then...Just a bit surprised when the idle got so rough at that temp, and trying to pick the revs up became more and more difficult the hotter it got.
Maybe I was a bit previous... I will have to reconnect the OBDII plug which I am relocating in the cab, and then 'see' what my App tells me. Its probable that its picked up some error-codes through me messing around - need to check all the sensors are in place, and I will reset the system I think and try again.
On the water-fill exercise, whats the best method of ensuring all air is out of the system?
cheers
Edited by V8 Vum on Tuesday 9th November 08:13
maybe your fuel is too hot, are you using the factory routing for the LS engines, if so then there is no fuel returned to the tank and at idle the consumation is very little so the fuel in the rails can get quite hot. the water temp should have no effect on the idle or throttle pick up unless you have blown your gaskets already.....a joke
Keith,
think I have the same engine as you from JS (675 HP)?
With the original mapping my engine ran way too rich, the cats began to glow red after some minutes.
Had to stop it to avoid damage to the cats.
Rough idle, bad response to the throttle. Maybe the same problem?
Do you run cats?
The ECU was remapped (a copy of Mr. Snood`s map that was worked out on the dyno afaik).
The engine now runs bettter, not perfect, but I can drive the car. Need to do my own dyno run in the
future.
Regarding water temp, 90 - 95 degree is ok, water does not boil at 100 degree in a pressurised system.
Check if the return line from the cooler (driver side in your case, connected to the thermostat housing)
is hot. If not the thermostat has not opened yet.
Check the fans circuit by shorting the contacts of the themostat switch. Do the fans run?
My two uprated fans blew the 30 A fuse every time they kicked in, had to use 40 A.
Michael
think I have the same engine as you from JS (675 HP)?
With the original mapping my engine ran way too rich, the cats began to glow red after some minutes.
Had to stop it to avoid damage to the cats.
Rough idle, bad response to the throttle. Maybe the same problem?
Do you run cats?
The ECU was remapped (a copy of Mr. Snood`s map that was worked out on the dyno afaik).
The engine now runs bettter, not perfect, but I can drive the car. Need to do my own dyno run in the
future.
Regarding water temp, 90 - 95 degree is ok, water does not boil at 100 degree in a pressurised system.
Check if the return line from the cooler (driver side in your case, connected to the thermostat housing)
is hot. If not the thermostat has not opened yet.
Check the fans circuit by shorting the contacts of the themostat switch. Do the fans run?
My two uprated fans blew the 30 A fuse every time they kicked in, had to use 40 A.
Michael
Well I reconnected the ODBII plugged in and.......
Remember I said that after the engine got to running temp, it started to idle very roughly..and got worse until it would not respond to the throttle? ..which is where I shut it down.... well
The trusty ipod rev app tells me that I now have a cam sensor circuit fault!
Clearing the codes and trying to start is useless just fluffs around..and stops
Disconnected the cam plug, cleaned and reconnected ...still the same
Grrrrrr...now what! ..and of course it is right at the front of the engine...not much chance of fixing it without the engine out..if that is what it is...
You know...if it wasn't for you Guys out there, I think I would have given up ages ago...
...must be my age! ..and I feel lonely!
I'm so peed off - going to have a very stiff G&T S@d it!
Remember I said that after the engine got to running temp, it started to idle very roughly..and got worse until it would not respond to the throttle? ..which is where I shut it down.... well
The trusty ipod rev app tells me that I now have a cam sensor circuit fault!
Clearing the codes and trying to start is useless just fluffs around..and stops
Disconnected the cam plug, cleaned and reconnected ...still the same
Grrrrrr...now what! ..and of course it is right at the front of the engine...not much chance of fixing it without the engine out..if that is what it is...
You know...if it wasn't for you Guys out there, I think I would have given up ages ago...
...must be my age! ..and I feel lonely!
I'm so peed off - going to have a very stiff G&T S@d it!
V8 Vum said:
Like http://www.demon-tweeks.co.uk/Motorsport/Cooling_S...
But where do you put it? Not much room!
Cheers
Put it in the front, just behind the radiator input.But where do you put it? Not much room!
Cheers
As you know a pump pushes it doesnot pull.
The pump on the engine is rpm related, and at low refs there is low flow.
That is not nice if you come from a highway and have to stop for a light.
the engine heats up and you have not aenough flow.
Then the electrical pump keeps pushing the water through the radiator and through the blok.
Keith
this is the best way to ensure no air in your system.
http://buy1.snapon.com/catalog/item.asp?store=snap...
I know its snapon but its about £70.. it sucks all the air out of your system and then sucks the coolant in... Guarenteed, no spillage no air locks.
I ve used these for years and you can fill your coolant system from empty in about 1 minute.
Dom
this is the best way to ensure no air in your system.
http://buy1.snapon.com/catalog/item.asp?store=snap...
I know its snapon but its about £70.. it sucks all the air out of your system and then sucks the coolant in... Guarenteed, no spillage no air locks.
I ve used these for years and you can fill your coolant system from empty in about 1 minute.
Dom
V8 Vum said:
Well I reconnected the ODBII plugged in and.......
Remember I said that after the engine got to running temp, it started to idle very roughly..and got worse until it would not respond to the throttle? ..which is where I shut it down.... well
The trusty ipod rev app tells me that I now have a cam sensor circuit fault!
Clearing the codes and trying to start is useless just fluffs around..and stops
Disconnected the cam plug, cleaned and reconnected ...still the same
Grrrrrr...now what! ..and of course it is right at the front of the engine...not much chance of fixing it without the engine out..if that is what it is...
You know...if it wasn't for you Guys out there, I think I would have given up ages ago...
...must be my age! ..and I feel lonely!
I'm so peed off - going to have a very stiff G&T S@d it!
calm down most likely it is not the sensor as this only a hall effect sensor and they are not too sensitive. If you have a scope and some skills in this direction you would be able to see if there is an output. You could even verify this with a multimeter when cranking.Remember I said that after the engine got to running temp, it started to idle very roughly..and got worse until it would not respond to the throttle? ..which is where I shut it down.... well
The trusty ipod rev app tells me that I now have a cam sensor circuit fault!
Clearing the codes and trying to start is useless just fluffs around..and stops
Disconnected the cam plug, cleaned and reconnected ...still the same
Grrrrrr...now what! ..and of course it is right at the front of the engine...not much chance of fixing it without the engine out..if that is what it is...
You know...if it wasn't for you Guys out there, I think I would have given up ages ago...
...must be my age! ..and I feel lonely!
I'm so peed off - going to have a very stiff G&T S@d it!
If you have a pinout of your ECU plug I would first test the connection from cam sensor to ECU see if the harness is ok, maybe one pin failed not properly crimped can easily happen with changed temperature.
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