Hot running issues
Discussion
Yeah, an old chestnut I know but anyone with similar experiences/advice could help me out here.
All the temps given are off the dash gauge - I have no reason not to trust it but of course it could be at fault. Car is a standard 500 (or as standard as they come!)
1. It comes to temp VERY quickly. Within 10 mins from cold it is already well on the way to 80. Could be a dodgy thermostat but I think that has been checked.
2. Soon after it reaches 90, even if I'm blatting up the motorway / A roads.
3. There it stays. Fans come in and kick out, in traffic mostly always on. My otter is at bottom of rads.
4. That is then pretty much equilibrium. Though I had a rough time last week in Blackpool when it briefly climbed over 100. Stopped, shorted the otter feed leads to relay to keep fans on and off again.
5. With fans always on it sits at about 85 which seems a bit high with constant fans.
Steve Howard has given it a fair bit of attention and without further exhuastive investigation he can only suggest at the moment that the cam may be wearing (car has done 31k, some cams go as low as 25k I believe).
One other odd thing. Driving on motorway a week back I noticed the gauge dive down from 90 to 70 and then flicker back up. Did this twice that I noticed. Could be an airlock I suppose if the sensor is briefly in air not water?
Car doesn't use much coolant/oil at all so no leaks apparent. No mayo in the oil filler and oil stays quite clean so don't suspect any bad gaskets. Always get hot air from the heater matrix (don't we all regardless of setting!)
Otter is the 92 on 88 off version.
Any help appreciated
Cheers
Dave
>>> Edited by donatien on Monday 27th September 19:44
All the temps given are off the dash gauge - I have no reason not to trust it but of course it could be at fault. Car is a standard 500 (or as standard as they come!)
1. It comes to temp VERY quickly. Within 10 mins from cold it is already well on the way to 80. Could be a dodgy thermostat but I think that has been checked.
2. Soon after it reaches 90, even if I'm blatting up the motorway / A roads.
3. There it stays. Fans come in and kick out, in traffic mostly always on. My otter is at bottom of rads.
4. That is then pretty much equilibrium. Though I had a rough time last week in Blackpool when it briefly climbed over 100. Stopped, shorted the otter feed leads to relay to keep fans on and off again.
5. With fans always on it sits at about 85 which seems a bit high with constant fans.
Steve Howard has given it a fair bit of attention and without further exhuastive investigation he can only suggest at the moment that the cam may be wearing (car has done 31k, some cams go as low as 25k I believe).
One other odd thing. Driving on motorway a week back I noticed the gauge dive down from 90 to 70 and then flicker back up. Did this twice that I noticed. Could be an airlock I suppose if the sensor is briefly in air not water?
Car doesn't use much coolant/oil at all so no leaks apparent. No mayo in the oil filler and oil stays quite clean so don't suspect any bad gaskets. Always get hot air from the heater matrix (don't we all regardless of setting!)
Otter is the 92 on 88 off version.
Any help appreciated
Cheers
Dave
>>> Edited by donatien on Monday 27th September 19:44
Do you know what temperature stat you have fitted?
Those symptoms suggest that the gauge might be lying. There are several ways you can cross check the reading. The easiest is to see what temperature the gauge shows at the point the fans come on. You can also measure the resistance of the ECU coolant temp sensor, which is at the front of the inlet manifold close to the sender for the temperature gauge. The sender for the gauge has a stud with a single wire connected to it. The sender for the ECU has a two pin connector similar to the ones on the injectors. You can also measure the sender resistance at a known temperature by taking it out of the car and sticking it in a pan of boiling water, and see what reading the gauge shows when it is connected to that resistance. If you take the pressure cap off, the engine won't go over 100 C without boiling. It should tick over happily with the pressure cap off, with the fans holding the temperature below 95 C. If the gauge shows over 100C with the pressure cap off and the engine isn't boiling, that shows the gauge is reading high. You will know it is boiling because it will spit water out, and the noise of boiling water in the heads is audible when the engine is running and very obvious when its switched off. Be carefull just in case the gauge is not lying and the engine really is boiling, because if you leave it boiling for prolonged periods you can cause local overheating in the heads. But a minute or so ticking over gently is OK, so waiting to see if the engine boils is a reasonable test to do.
Those symptoms suggest that the gauge might be lying. There are several ways you can cross check the reading. The easiest is to see what temperature the gauge shows at the point the fans come on. You can also measure the resistance of the ECU coolant temp sensor, which is at the front of the inlet manifold close to the sender for the temperature gauge. The sender for the gauge has a stud with a single wire connected to it. The sender for the ECU has a two pin connector similar to the ones on the injectors. You can also measure the sender resistance at a known temperature by taking it out of the car and sticking it in a pan of boiling water, and see what reading the gauge shows when it is connected to that resistance. If you take the pressure cap off, the engine won't go over 100 C without boiling. It should tick over happily with the pressure cap off, with the fans holding the temperature below 95 C. If the gauge shows over 100C with the pressure cap off and the engine isn't boiling, that shows the gauge is reading high. You will know it is boiling because it will spit water out, and the noise of boiling water in the heads is audible when the engine is running and very obvious when its switched off. Be carefull just in case the gauge is not lying and the engine really is boiling, because if you leave it boiling for prolonged periods you can cause local overheating in the heads. But a minute or so ticking over gently is OK, so waiting to see if the engine boils is a reasonable test to do.
GreenV8S said:
Do you know what temperature stat you have fitted?
Those symptoms suggest that the gauge might be lying. There are several ways you can cross check the reading. The easiest is to see what temperature the gauge shows at the point the fans come on. You can also measure the resistance of the ECU coolant temp sensor, which is at the front of the inlet manifold close to the sender for the temperature gauge. The sender for the gauge has a stud with a single wire connected to it. The sender for the ECU has a two pin connector similar to the ones on the injectors. You can also measure the sender resistance at a known temperature by taking it out of the car and sticking it in a pan of boiling water, and see what reading the gauge shows when it is connected to that resistance. If you take the pressure cap off, the engine won't go over 100 C without boiling. It should tick over happily with the pressure cap off, with the fans holding the temperature below 95 C. If the gauge shows over 100C with the pressure cap off and the engine isn't boiling, that shows the gauge is reading high. You will know it is boiling because it will spit water out, and the noise of boiling water in the heads is audible when the engine is running and very obvious when its switched off. Be carefull just in case the gauge is not lying and the engine really is boiling, because if you leave it boiling for prolonged periods you can cause local overheating in the heads. But a minute or so ticking over gently is OK, so waiting to see if the engine boils is a reasonable test to do.
Peter,
Think it's a standard 72 (or 75 not sure) stat. As far as I know it has the small holes to allow some premature bleed and is fitted the right way up. Heard a rumour that they need to be fitted in correct orientation.
The fans do come on at just over 90 registered on gauge so it seems right. Of course there is potentially a difference between the measurement (and hence actuation) the otter takes at bottom of rads and the temp gauge sender on the block.
I have seen 95-100 on gauge and fans still off. They usually come on a bit later but at that point I decide it's time to stop.
Also, if I park up and return to the car within a few minutes as I drive off the gauge sometimes tells me a higher reading than when I turned it off, again 95-100 when it showed 90 a few minutes previously. It does then settle down to 90 though.
It's that difference in otter/gauge that bugs me. Gauge can say almost 100 with no fans on at which point I take corrective action.
If indeed the gauge is lying it still doesn't explain why my fans are on so often? The weather isn't that hot at moment.
One last thing that may cast some light. In damp weather I sometimes get the odd situation that the fans are always on - indicating a bad earth or wiring from otter to relays? This goes away after a day or so.
Thanks for the help, appreciate it
Dave
Guillotine said:
duff otter switch...fans not cutting in occasionally?
bad earth for the fans...not cutting in again occasionally.
(heat soak will build up temp in the block after shut off as there is no water circulation only thermal conduction. normal)
change the otter.
IMHO
Bad earth sounding likely
especially as the fans can be stuck on in the damp Luckily I'm now just down the road from TVR in Lytham so maybe they can squeeze me in for a check
Edited to add - the otter is fine actually. Had it in boiling water and it kicks in out about right (didn't measure it exactly but it does trip both ways)
>> Edited by donatien on Monday 27th September 21:51
>> Edited by donatien on Monday 27th September 21:52
its only an intermittent prob tho isn't it? may not work every time. 9 out of 10?
for the price i'd change it anyway.
the rapid change in temp would be electrical. the water system can't change that quick. got to be the sensor or conections. change the sensor too. again cheap.
>> Edited by Guillotine on Monday 27th September 21:58
for the price i'd change it anyway.
the rapid change in temp would be electrical. the water system can't change that quick. got to be the sensor or conections. change the sensor too. again cheap.
>> Edited by Guillotine on Monday 27th September 21:58
Sounds like a number of things to me:
Check radiator - remember that its a modified to fit but standard land rover 3 core unit - I have upgraded mine to 4 core
Air blocks - the car shouldnt sit at 85 or 90 on a motorway (unless stationary) - I have had a similar issue in the past, as I put my foot down the speed and temperature both climbed (scary)I now regularly check, bleed and top up the system via the brass nut
ALSO : fit kenlow unit and leven water wetter
no problems since
Check radiator - remember that its a modified to fit but standard land rover 3 core unit - I have upgraded mine to 4 core
Air blocks - the car shouldnt sit at 85 or 90 on a motorway (unless stationary) - I have had a similar issue in the past, as I put my foot down the speed and temperature both climbed (scary)I now regularly check, bleed and top up the system via the brass nut
ALSO : fit kenlow unit and leven water wetter
no problems since
I think your car could be cured with a few simple, but not cheap fixes .. either a new gauge if it's not overheating but telling porkies, or a resistor in the wire to it to make it read the correct value .. or just accept it'll overread.
if the temp is actually that high then you need to think about replacing the rad, thermostat again and otter switch .. if all those things are working properly it will run properly, if the temp is climbing it's because one or more is faulty .. for the sake of 300 pounds you can replace them all and have total peace of mind.
>> Edited by joospeed on Wednesday 29th September 20:30
if the temp is actually that high then you need to think about replacing the rad, thermostat again and otter switch .. if all those things are working properly it will run properly, if the temp is climbing it's because one or more is faulty .. for the sake of 300 pounds you can replace them all and have total peace of mind.
>> Edited by joospeed on Wednesday 29th September 20:30
joospeed said:
I think your car could be cured with a few simple, but not cheap fixes .. either a new gauge if it's not overheating but telling porkies, or a resistor in the wire to it to make it read the correct value .. or just accept it'll overread.
if the temp is actually that high then you need to think about replacing the rad, thermostat again and otter switch .. if all those things are working properly it will run properly, if the temp is climbing it's because one or more is faulty .. for the sake of 300 pounds you can replace them all and have total peace of mind.
>> Edited by joospeed on Wednesday 29th September 20:30
Yeah, probably best to get sorted.
Would a worn cam make it run hotter? If the valves aint opening at the right rate it could run a bit lean which means hotter.
I'm sure it is something that can be fixed (and I do ant it fixed) for a bit of cash.
If it is a cam is there any benefit in getting any other work done at the same time? I'm not looking to get it up to 300+ bhp or so but maybe there are better everyday cams available over the standard
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