Freakn' cooling system. - where to go from here
#46
Burning Brakes
Thread Starter
Hard to tell with a turbo. There is so much stuff in the way you can't easily get your hand in front of the fans without your fingers getting hit by the blades. That being said the fan seem like they're really getting after it from what I can see and if I put a piece of paper on the front of the radiator it gets sucked to it flat right away.
Last edited by Last Lemming; 05-21-2016 at 12:43 PM.
#48
Burning Brakes
Thread Starter
#49
I would take the radiator to a radiator shop and let them check it. Sounds like the fans are not removing the heat from the radiator. I know that you said the radiator is new but you never know. Let us know how you make out.
#50
Burning Brakes
Thread Starter
While certainly a possibility - why would the car cool just fine once on the move?
#51
Addict
Rennlist Member
Rennlist Member
A couple of thoughts. Was it doing this before replacing the water pump? Was thinking the impeller on the wp shaft could be slipping.
When you put the new radiator in was the thermoswitch corroded badly. If so that can act as an insulation, make sure it is good and clean and functioning properly.
When you put the new radiator in was the thermoswitch corroded badly. If so that can act as an insulation, make sure it is good and clean and functioning properly.
#52
Is it possible the small radiator vent hose (left radiator tank to expansion tank) blocked keeping the radiator air bound?
#53
Burning Brakes
Thread Starter
A couple of thoughts. Was it doing this before replacing the water pump? Was thinking the impeller on the wp shaft could be slipping.
When you put the new radiator in was the thermoswitch corroded badly. If so that can act as an insulation, make sure it is good and clean and functioning properly.
When you put the new radiator in was the thermoswitch corroded badly. If so that can act as an insulation, make sure it is good and clean and functioning properly.
As for the impeller - it depends on how it's attached. I did mark pulley relative to what seems like then end of the shaft and I haven't seen any rotation. However if the impeller is pressed on to a shaft behind the pulley then slippage is possible I suppose. It's a new Laso pump. I wonder what the fail rate is on them.
#54
Burning Brakes
Thread Starter
A couple of thoughts. Was it doing this before replacing the water pump? Was thinking the impeller on the wp shaft could be slipping.
When you put the new radiator in was the thermoswitch corroded badly. If so that can act as an insulation, make sure it is good and clean and functioning properly.
When you put the new radiator in was the thermoswitch corroded badly. If so that can act as an insulation, make sure it is good and clean and functioning properly.
#55
Three Wheelin'
My fault Last Lemming, after looking at your video, I realized the foam strip mounts to the shroud that goes under the intercooler & butts up against the top of the radiator.
Another thing I'm wondering is the fans aren't receiving enough voltage so they are turning slower thus not moving as much air. They should cycle on and off at idle.
Another thing I'm wondering is the fans aren't receiving enough voltage so they are turning slower thus not moving as much air. They should cycle on and off at idle.
#56
Addict
Rennlist Member
Rennlist Member
I had a spun water pump impeller and it'd overheat at speed. It seemed to move a little water at idle but no way enough when driving, even slowly.
It sounds like the radiator is dropping heat appropriately at idle with the fan running. If true this means you do not have enough water flow through the radiator at idle, or too much heat is being produced.
You say the thermostat is new but is that new, replaced since the problem was identified or new from some other work? I dislike running without a thermostat (fat running, carbon deposits, etc.) but it'd be worth trying.
I wonder if it's just leaning out or otherwise running hot at idle? Or maybe always? O2 sensor?
The cat inlet and maybe the hotside should glow red at 525F or so and if this is happening at idle that's probably no bueno. It might take a while to heat up the hotside but the cat, before the heatshield and just after, should get hot quick.
It sounds like the radiator is dropping heat appropriately at idle with the fan running. If true this means you do not have enough water flow through the radiator at idle, or too much heat is being produced.
You say the thermostat is new but is that new, replaced since the problem was identified or new from some other work? I dislike running without a thermostat (fat running, carbon deposits, etc.) but it'd be worth trying.
I wonder if it's just leaning out or otherwise running hot at idle? Or maybe always? O2 sensor?
The cat inlet and maybe the hotside should glow red at 525F or so and if this is happening at idle that's probably no bueno. It might take a while to heat up the hotside but the cat, before the heatshield and just after, should get hot quick.
#58
Burning Brakes
Thread Starter
I had a spun water pump impeller and it'd overheat at speed. It seemed to move a little water at idle but no way enough when driving, even slowly.
It sounds like the radiator is dropping heat appropriately at idle with the fan running. If true this means you do not have enough water flow through the radiator at idle, or too much heat is being produced.
You say the thermostat is new but is that new, replaced since the problem was identified or new from some other work? I dislike running without a thermostat (fat running, carbon deposits, etc.) but it'd be worth trying.
I wonder if it's just leaning out or otherwise running hot at idle? Or maybe always? O2 sensor?
The cat inlet and maybe the hotside should glow red at 525F or so and if this is happening at idle that's probably no bueno. It might take a while to heat up the hotside but the cat, before the heatshield and just after, should get hot quick.
It sounds like the radiator is dropping heat appropriately at idle with the fan running. If true this means you do not have enough water flow through the radiator at idle, or too much heat is being produced.
You say the thermostat is new but is that new, replaced since the problem was identified or new from some other work? I dislike running without a thermostat (fat running, carbon deposits, etc.) but it'd be worth trying.
I wonder if it's just leaning out or otherwise running hot at idle? Or maybe always? O2 sensor?
The cat inlet and maybe the hotside should glow red at 525F or so and if this is happening at idle that's probably no bueno. It might take a while to heat up the hotside but the cat, before the heatshield and just after, should get hot quick.
One caveat here is that the AC condenser radiator is not on the car currently. It is getting tested and cleaned so I don't know how much that had to do with hindering the cooling process however it was not dirty at all on the outside when I took it off.
I also bled the system very well and even rented a pump to pressurize the system to get rid of any extraneous small bubble.
One thought I'm having is the impeller does not have a tight enough tollerence and I could just not be flowing enough coolant at low RPM because the gap between the back of the impeller in the block is too great, but at higher RPM it follows enough
#59
Addict
Rennlist Member
Rennlist Member
Some observations before I forget, stock 1992 968.
72F degree day, sunny. Exterior temp gauge showing 75-80F due to sun and hot roads.
Fully warmed up after 25 mile drive. Radiator hoses near radiator, idling in the driveway, 195 degrees in 145-150 degrees outlet.
On the highway, top down, AC on, 75 mph I get almost to the top thin white line on the gauge.
AC off, 75 mph, at middle of the gauge
AC off, 60-65mph, maybe 1-2mm over the lower white line
AC off, 45mph, pretty much on the lower white line
AC off, 25mph (neighborhood) just below the middle of the gauge (note, warmer than 45mph cuise)
AC off, idling, just above the lower white line. Some fans running.
72F degree day, sunny. Exterior temp gauge showing 75-80F due to sun and hot roads.
Fully warmed up after 25 mile drive. Radiator hoses near radiator, idling in the driveway, 195 degrees in 145-150 degrees outlet.
On the highway, top down, AC on, 75 mph I get almost to the top thin white line on the gauge.
AC off, 75 mph, at middle of the gauge
AC off, 60-65mph, maybe 1-2mm over the lower white line
AC off, 45mph, pretty much on the lower white line
AC off, 25mph (neighborhood) just below the middle of the gauge (note, warmer than 45mph cuise)
AC off, idling, just above the lower white line. Some fans running.