280i temparature
Discussion
Does this sort of stuff work? ..... Rad Flush
using various potions is an accepted way of cleaning domestic heating systems
using various potions is an accepted way of cleaning domestic heating systems
Update: I've had partial success by making up a radiator shroud our of galv sheet spaced as far back from the rad as possible which wasn't very far, maybe 2 inches. Result is that the car get to temp quicker due to less airflow with fan off, but when the fan comes on, it is far more effective than it was pre-shroud at pulling the temp down.
However...
I got an infrared thermometer gun to see what was going on. This tells me that:
1. The fan thermoswitch is set to come on at 85C and does, exactly. However the sensor is at the bottom of the rad,
2. The temp gauge sensor is at the top of the engine and reads fairly accurately.
3. Water that is going back to the rad is typically 90-92C which seems too hot.
So it seems the engine heats up the water by around 7 degrees from when it enters to when it exits. I don't know what temp the fan is set to switch off but I think it's going off too soon.
The thermostat is 82C so if is keep the fan on longer by swapping out the sender or getting an adjustable one, the stat will close!
Taking out the thermostat is unwise because the water will flow faster and the rad won;t be able to cool it before it goes back into the engine.
So my thinking is that (short of buying a custom radiator) I need a lower temp thermostat (anyone know if they exist?) and a thermoswith (otter) that keeps the fan on longer.
Does that make sense?
However...
I got an infrared thermometer gun to see what was going on. This tells me that:
1. The fan thermoswitch is set to come on at 85C and does, exactly. However the sensor is at the bottom of the rad,
2. The temp gauge sensor is at the top of the engine and reads fairly accurately.
3. Water that is going back to the rad is typically 90-92C which seems too hot.
So it seems the engine heats up the water by around 7 degrees from when it enters to when it exits. I don't know what temp the fan is set to switch off but I think it's going off too soon.
The thermostat is 82C so if is keep the fan on longer by swapping out the sender or getting an adjustable one, the stat will close!
Taking out the thermostat is unwise because the water will flow faster and the rad won;t be able to cool it before it goes back into the engine.
So my thinking is that (short of buying a custom radiator) I need a lower temp thermostat (anyone know if they exist?) and a thermoswith (otter) that keeps the fan on longer.
Does that make sense?
I still think the starting point here should be to have the rad re-cored before you go mucking about with ancillaries. Yes I know you've had it flushed but those water channels are so small they easily clog up with muck which solidifies over the years and no amount of flushing will shift it.
440Interceptor said:
1. The fan thermoswitch is set to come on at 85C and does, exactly. However the sensor is at the bottom of the rad,
2. The temp gauge sensor is at the top of the engine and reads fairly accurately.
3. Water that is going back to the rad is typically 90-92C which seems too hot.
Presumably that is stationary with the fan running? Although if your 'stat opens at 82C and your temp sender unit and gauge are accurate and showing 85C then you can assume this is pretty much what is happening on the move as well.
Doesn't sound much of a temperature drop across the rad to me. How does that compare with other cars?
Good question, I don't know, but I'm going to buy one of those thermometers and find out on my other cars.
I'd also like to know what the ideal temp for the Cologne motor is. Presumably somewhere around mid 80s C.
It also seems the motor is heating the water up 7 degrees - in at 85 and out at 92, and that shouldn't change much. So If i want it coming out the top at mid-high 80s then it needs to go in the bottom a little cooler than it currently is. BUT with the switch turning off the fan at 85 that will never happen.
You know what, a fan override switch will be a cheap way to test the theory... fan on longer should get temp down to 82 before the stat closes...
I'd also like to know what the ideal temp for the Cologne motor is. Presumably somewhere around mid 80s C.
It also seems the motor is heating the water up 7 degrees - in at 85 and out at 92, and that shouldn't change much. So If i want it coming out the top at mid-high 80s then it needs to go in the bottom a little cooler than it currently is. BUT with the switch turning off the fan at 85 that will never happen.
You know what, a fan override switch will be a cheap way to test the theory... fan on longer should get temp down to 82 before the stat closes...
440Interceptor said:
.....You know what, a fan override switch will be a cheap way to test the theory... fan on longer should get temp down to 82 before the stat closes...
Not necessarily. It depends on how quickly the coolant is flowing through the rad. The slower it moves through the greater the cooling effect of the flowing air and vice-versa. The rad is just a simple heat exchanger. The coolant needs to be in there just long enough for the air to remove the required amount of heat. I had a 82 degree stat fitted..It used to get to around 87 degrees before the fan would come on to allow full opening of the stat...anything under 90 is okay for a Cologne....as said as long as the flow is good then you should be okay...If it were me I would ditch the viscous fan as that is pants and just uses up horses...It essentially just blows the heat around the engine bay which is not good for a fibreglass car...get yourself a decent 16-17" Kenlowe fan, ideally a puller if you can remove the viscous fan...then you won't need to worry...
Ziga
Ziga
If someone with a 280i and a stock rad (recently re-cored ideally) can measure the temps at the top and bottom hoses you'll know what sort of temperature reduction you should be looking for.
One of THESE will come in handy. If you're prepared to wait they are about a third that price from China.
One of THESE will come in handy. If you're prepared to wait they are about a third that price from China.
Classic Chim said:
Can you get an alley rad for these cars as I have one in my 4.6 Chim and its very effective. For a few hundred quid it’s a good investment imo
I've had two alloy rads in my V8S (@ £400+ ea) and have gone back to OE copper. Both alloy rads failed after a relatively short time and the car now runs cooler with the old style rad.v8s4me said:
I've had two alloy rads in my V8S (@ £400+ ea) and have gone back to OE copper. Both alloy rads failed after a relatively short time and the car now runs cooler with the old style rad.
I’ve heard similar things about one or two fitted to Chims. I fail to see how forces can be applied to distort and break it as in the case of the so called Chim issue. I added new bobbins and made sure the lugs fitted loosely at the base and mines been good until now. I think it’s 5 years or more since it was fitted.
Different cars so no point comparing I suppose. Mine runs cooler quicker with alley rad but other than that it seems to do a similar job as the original.
I’d agree if the rad takes shocks or vibration your better off staying O/E
As I’ve removed mine about 3 times I’ll say it’s a lot lighter
Classic Chim said:
Can you get an alley rad for these cars as I have one in my 4.6 Chim and its very effective.
For a few hundred quid it’s a good investment imo
Hi mateFor a few hundred quid it’s a good investment imo
I think the original V6 rad was 2.5 core and I had mine rebuilt to 3 core...however the onset of a supercharger meant big changes, Tim at ACT sorted me out a few years back with an alloy rad...
I then fitted an 18" turbo boost Kenlowe....Shame about the dodgy heads I bought...
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