k-series idle water temperature problems
Discussion
Hi,
I have a question concerning your experiences with the water temperature during idle in a 1.8l (200 bhp) k-series superlight.
My engine is running a modified and blanked VVC head with 285H cams on 42 mm ITBs controlled by an Emerald K6. The exhaust consists of long 4 in 1 primaries with a cat and the R500 silencer and I have a QED remote thermostat installed.
I modified the fan control by adding a ECU controlled relay to switch the fan depending on the ECU measured water temperature independent of the thermo switch which is still in place.
When I finally got my homemade CAN Display installed this summer I noticed that the ECU measured temperatures were quite a bit higher (ca. 12-15 °C) than the values showing on the analog gauge. During normal operation on road and track the water temperature will stay around 82 °(ECU) which shows me that my thermostat and the water pump must generally be working correctly.
When sitting in traffic before I did the relay mod I noticed that the water temperatures were rising over 100° without the fan kicking in, so I checked for possible air bubbles in the radiator (found none) and in the end installed the ECU fan control. Now the fan starts to kick in at whatever temperature I like, but nevertheless the temps still keep climbing above 100° when idling for a longer time. As soon as I get to move again the temperatures drop rather quickly.
I would assume that there are two possible causes for this behavior and I would really appreciate if you could comment my thoughts on this matter.
1. The water pump capacity is too low at idle, so the engine gets hot because of a lack of sufficient water flow.
2. The primaries under the bonnett radiate a lot of heat into the water rail/temperature senders, so that the measured temperature is actually higher than the correct temperature of the water leaving the cylinder head.
Assuming that the thermoswitch is still working the fact that the fan was not kicking in before the mod would suggest that the water entering the radiator was not as hot as the ECU temp sender says. Checking the water rail temperatures with an infrared thermometer showed a decreasing gradient of measured temperatures starting from the head moving on towards the end of the water rail which coincides with the distance of the primaries to the water rail.
Did anybody experience similar problems and could advise a solution?
Do you have any suggestions how to further diagnose my problem?
Do you know a way to check my cooling flow at idle?
Thanks for reading this rather long post and I would appreciate any help.
Felix
I have a question concerning your experiences with the water temperature during idle in a 1.8l (200 bhp) k-series superlight.
My engine is running a modified and blanked VVC head with 285H cams on 42 mm ITBs controlled by an Emerald K6. The exhaust consists of long 4 in 1 primaries with a cat and the R500 silencer and I have a QED remote thermostat installed.
I modified the fan control by adding a ECU controlled relay to switch the fan depending on the ECU measured water temperature independent of the thermo switch which is still in place.
When I finally got my homemade CAN Display installed this summer I noticed that the ECU measured temperatures were quite a bit higher (ca. 12-15 °C) than the values showing on the analog gauge. During normal operation on road and track the water temperature will stay around 82 °(ECU) which shows me that my thermostat and the water pump must generally be working correctly.
When sitting in traffic before I did the relay mod I noticed that the water temperatures were rising over 100° without the fan kicking in, so I checked for possible air bubbles in the radiator (found none) and in the end installed the ECU fan control. Now the fan starts to kick in at whatever temperature I like, but nevertheless the temps still keep climbing above 100° when idling for a longer time. As soon as I get to move again the temperatures drop rather quickly.
I would assume that there are two possible causes for this behavior and I would really appreciate if you could comment my thoughts on this matter.
1. The water pump capacity is too low at idle, so the engine gets hot because of a lack of sufficient water flow.
2. The primaries under the bonnett radiate a lot of heat into the water rail/temperature senders, so that the measured temperature is actually higher than the correct temperature of the water leaving the cylinder head.
Assuming that the thermoswitch is still working the fact that the fan was not kicking in before the mod would suggest that the water entering the radiator was not as hot as the ECU temp sender says. Checking the water rail temperatures with an infrared thermometer showed a decreasing gradient of measured temperatures starting from the head moving on towards the end of the water rail which coincides with the distance of the primaries to the water rail.
Did anybody experience similar problems and could advise a solution?
Do you have any suggestions how to further diagnose my problem?
Do you know a way to check my cooling flow at idle?
Thanks for reading this rather long post and I would appreciate any help.
Felix
Not sure how similar it will be but running a K series in a mid engine car it is considered that the water pump is a little lazy at idle.
If you raise the idle a little does the temp drop?
You could check the flow by swopping in a length of clear hose (available from Aquarium/pond shops) just don't get it too hot. I seem to remember someone doing this with a bit of ribbon in the tube. I may be mad though and I would be concerned it may come off and end up in the engine somewhere!
If you raise the idle a little does the temp drop?
You could check the flow by swopping in a length of clear hose (available from Aquarium/pond shops) just don't get it too hot. I seem to remember someone doing this with a bit of ribbon in the tube. I may be mad though and I would be concerned it may come off and end up in the engine somewhere!
Have you tried insulating the water rail to reduce the influence on the measurement?
I know that many people wrap their primaries to reduce the heat under the bonnet, but I am not really fond of insulating the primaries. I would then expect the heat transfer from the exhaust manifold to the head to become even worse, since cylinder head temperatures especially around the exhaust valves are rather critical.
I guess the best would be to measure the water temperatures at a different location.
Are there any sensible solutions that have proven to work?
P.S. Raising the idle speed seems to make it a little worse. That is why I tend to think that the measurement is influenced by the hot air under the bonnet and by radiation and not by insufficient coolant flow
I know that many people wrap their primaries to reduce the heat under the bonnet, but I am not really fond of insulating the primaries. I would then expect the heat transfer from the exhaust manifold to the head to become even worse, since cylinder head temperatures especially around the exhaust valves are rather critical.
I guess the best would be to measure the water temperatures at a different location.
Are there any sensible solutions that have proven to work?
P.S. Raising the idle speed seems to make it a little worse. That is why I tend to think that the measurement is influenced by the hot air under the bonnet and by radiation and not by insufficient coolant flow
I've nothing much constructive to add, but have thought the ECU temp sender above the primaries to be a little wrong, especially in a black pipe. I have revuilt my car with a black powder coated engine bay. The passenger footwell on my K series, which as you know is near the primaries, gets too hot to rest bare feet against when sitting as a passenger. So the water rail, although with moving water inside, must be going through something similar.
I plan to insulate the end of the passenger footwell, maybe I'll do the water rail also, it couldn't hurt could it?
I plan to insulate the end of the passenger footwell, maybe I'll do the water rail also, it couldn't hurt could it?
Move the temp senders out of the water rail into the bypass loop away from the exhaust - this was standard on the R500. http://www.caterhamparts.co.uk/product.php?id_prod...
sfaulds said:
Move the temp senders out of the water rail into the bypass loop away from the exhaust - this was standard on the R500. http://www.caterhamparts.co.uk/product.php?id_prod...
Does it use the same water rail but with blanked off tappings? Or a new rail? Where is the remote rail located?Gingerbread Man said:
Does it use the same water rail but with blanked off tappings? Or a new rail? Where is the remote rail located?
Yup. I've done this with my 220hp SLR. Although I'd be surprised if the rate of water flow even at idle is not enough to carry the heat radiated by the primaries away from the sender enough for it not to give an artificially high reading.
I inserted something like the image per the link below in the return pipe from the rad (sited above the DS pump) and mounted the water temp sender for the ECU in there.
http://www.dhgate.com/store/product/28mm-40mm-blue...
I also hard wired an override switch into the dash to be able to manually control the fan.
I also have the PRRT solution installed, with an 82 degree stat built into that, so that tends to be where my temps sit, regardless of use.
The car started its life as a 1.8 Superlight with 140 hp and I don't think the rad has ever been changed.
It is made of aluminum and looks a lot like this one
http://www.caterhamparts.co.uk/product.php?id_product=43
It is made of aluminum and looks a lot like this one
http://www.caterhamparts.co.uk/product.php?id_product=43
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