Weird Elise S2 cooling problem - advice sought
Discussion
Hi all
My S2 Elise Sport 135 (Rover engined) has developed a weird cooling problem this morning.
Ran it for 2 hours yesterday without issue, but today I was pootling along at 40mph and was horrified to see 103C on the readout!
I pulled into the nearest services (thankfully within 0.5mi), and checked the water level. It was fine - no lost water.
Then I checked the oil level (and condition) - was a tad low (topped it up) and it was in perfect condition (no mayonnaise). Water also looks fine.
Let the car cool down, then drove on to test it.
The water temperature readout is now very erratic:
generally on the move it stays around 90C. Go slowly, it rises dramatically, and stationary at lights it climbs above 100C scarily fast. Fan catches it, and brings it back to 95C, then on the move it can drop to 85C, then back up to 95C, down to 88C, up to 91C. But if I stop at the lights, the temperature rockets up.
Just checked the oil and water (1 hour later) and all is fine.
Any ideas? Sensor? Oil pump/oil pickup problem?
My S2 Elise Sport 135 (Rover engined) has developed a weird cooling problem this morning.
Ran it for 2 hours yesterday without issue, but today I was pootling along at 40mph and was horrified to see 103C on the readout!
I pulled into the nearest services (thankfully within 0.5mi), and checked the water level. It was fine - no lost water.
Then I checked the oil level (and condition) - was a tad low (topped it up) and it was in perfect condition (no mayonnaise). Water also looks fine.
Let the car cool down, then drove on to test it.
The water temperature readout is now very erratic:
generally on the move it stays around 90C. Go slowly, it rises dramatically, and stationary at lights it climbs above 100C scarily fast. Fan catches it, and brings it back to 95C, then on the move it can drop to 85C, then back up to 95C, down to 88C, up to 91C. But if I stop at the lights, the temperature rockets up.
Just checked the oil and water (1 hour later) and all is fine.
Any ideas? Sensor? Oil pump/oil pickup problem?
Hey Dave
Thanks for your post! Yeah, I thought it could be the sensor (I'm an engineer and always distrust sensors' reliability and precision). Do you know if the Stack's sensor gives regular issues? I've read that this could be it's "end of life" dance.
I'll check the sensor tomorrow.
Given that the oil and water are fine and uncontaminated, could it be something else fundamental (i.e. not sensor/display issues)?
Thanks for your post! Yeah, I thought it could be the sensor (I'm an engineer and always distrust sensors' reliability and precision). Do you know if the Stack's sensor gives regular issues? I've read that this could be it's "end of life" dance.
I'll check the sensor tomorrow.
Given that the oil and water are fine and uncontaminated, could it be something else fundamental (i.e. not sensor/display issues)?
- UPDATE* I have left the car for many hours now, and it's stone cold. Checked the water level in the overflow reservoir, and it was WAY low. When I checked the water originally, the car was still more-than-just-warm, and the coolant system was still pressurised. Had to relieve the pressure slowly by slowly removing the cap, and the water level was normal - with hot water. Now with the system unpressurised and cold water, it's extremely low.
bonehead said:
Hey Dave
Thanks for your post! Yeah, I thought it could be the sensor (I'm an engineer and always distrust sensors' reliability and precision). Do you know if the Stack's sensor gives regular issues? I've read that this could be it's "end of life" dance.
I'll check the sensor tomorrow.
Given that the oil and water are fine and uncontaminated, could it be something else fundamental (i.e. not sensor/display issues)?
Temp sensors do seem to get changed by many, I did mine in the S1 Elise. Thanks for your post! Yeah, I thought it could be the sensor (I'm an engineer and always distrust sensors' reliability and precision). Do you know if the Stack's sensor gives regular issues? I've read that this could be it's "end of life" dance.
I'll check the sensor tomorrow.
Given that the oil and water are fine and uncontaminated, could it be something else fundamental (i.e. not sensor/display issues)?
- UPDATE* I have left the car for many hours now, and it's stone cold. Checked the water level in the overflow reservoir, and it was WAY low. When I checked the water originally, the car was still more-than-just-warm, and the coolant system was still pressurised. Had to relieve the pressure slowly by slowly removing the cap, and the water level was normal - with hot water. Now with the system unpressurised and cold water, it's extremely low.
As for your edit, it could be the start of HGF, very common with the K series. However, have you noticed any steam/fluid fronm the front end?? May be a hose on the rad worked loose or the start of the famous failure of the end caps on the rad.
Just a thought but if you think it could be HGF then get it in sooner rather than later !
Thanks mate! Never seen steam (except on some rainy days when I assume rain water is evaporating on top of the radiator when I am stationary).
I'm gonna take it to the specialist and get him to pressure test the coolant system, then check for an imminent HGF.
I'll post the results as soon as I know, so anyone following this thread can see the closure.
I'm gonna take it to the specialist and get him to pressure test the coolant system, then check for an imminent HGF.
I'll post the results as soon as I know, so anyone following this thread can see the closure.
On my S1, whenever I've had the temp gauge randomness it's been the "other" way - it bounces between what I assume is the correct reading (92 say) downwards then back again. Or it will bounce between several random values, all below what I believe the engine is actually at. It never jumped to an artificially high reading. The main thing though is that it changes too fast for it to be a real temperature change.
HGF is a possibility, of course, and naturally the first thing that one thinks of when having any cooling related issues on a K. I have read that the S2 135R is particularly susceptible as the batch of heads that Lotus used on these were more than usually soft and porous.
Another alternative is that you have picked up a small pinhole leak in your radiator, possibly from a stone strike. If the coolant has then been allowed to drop below the bottom of the expansion tank it could have introduced a small airlock in the pipes, which could account for your erratic temperature readings. Check for signs of coolant leaks around the radiator, and possible coolant residue on the radiator air exit and windscreen. I had this a few thousand miles ago, with similar symptoms. Fixed the hole on the rad, topped up and bled the system, and all back to normal and running fine since.
Another alternative is that you have picked up a small pinhole leak in your radiator, possibly from a stone strike. If the coolant has then been allowed to drop below the bottom of the expansion tank it could have introduced a small airlock in the pipes, which could account for your erratic temperature readings. Check for signs of coolant leaks around the radiator, and possible coolant residue on the radiator air exit and windscreen. I had this a few thousand miles ago, with similar symptoms. Fixed the hole on the rad, topped up and bled the system, and all back to normal and running fine since.
HGF certainly, mine did the same thing. Exhaust gases are leaking into the coolant system and pressurising it, which is why the coolant level is low and still under pressure when cool, where normally it wouldn't be. Don't run it and be careful for hydrolock as once the engine isn't running the pressure in the system is forcing coolant back the other way into the cylinders.
The reason the temp is all over the place is that the sensor is designed to read in water and from time to time it's in air, or at least dissolved air.
Mine was caused by a failure across the fire ring (?)... not sure that was the exact phrase used mind you! Skimmed and shimmed I believe is the answer.
Textbook I'm afraid
The reason the temp is all over the place is that the sensor is designed to read in water and from time to time it's in air, or at least dissolved air.
Mine was caused by a failure across the fire ring (?)... not sure that was the exact phrase used mind you! Skimmed and shimmed I believe is the answer.
Textbook I'm afraid
I had similar symptoms from a small hole in the rad that leaked coolant when engine was under heavy load. Was that small that any leakage burned off without obvious steam. Coolant would not drop just pootling around town. So may not be dreaded HGF.
A specialist clocked it straight away as he could smell the coolant when stood at the front of the car and could see signs of the leak at the corner of the rad.
Could be a loose hose elsewhere of course.
A specialist clocked it straight away as he could smell the coolant when stood at the front of the car and could see signs of the leak at the corner of the rad.
Could be a loose hose elsewhere of course.
Had a chat with the specialist, and he is not sure yet what it is. He obviously needs to run some tests...but he said the fact that the car was able to control its temperature (with the fan) was promising.
The temperature reading did fluctuate, generally +-5C on an average of 90C, but then would rise when I slowed down/stopped and would cool down under the fan and then moving again. Checked oil again, nothing wrong, checked water reservoir, absolutely no sign of oil contamination. Specialist said it could be HGF causing water to enter the combustion chamber, where the water is simply burned away. Not a good thing, but not a catastrophe.
Scared to drive it though, so gonna arrange for a truck to pick it up and deliver it to the specialist.
Praying that the good sign (able to control the temperature) means it's something inocuous like a rad leak.
The temperature reading did fluctuate, generally +-5C on an average of 90C, but then would rise when I slowed down/stopped and would cool down under the fan and then moving again. Checked oil again, nothing wrong, checked water reservoir, absolutely no sign of oil contamination. Specialist said it could be HGF causing water to enter the combustion chamber, where the water is simply burned away. Not a good thing, but not a catastrophe.
Scared to drive it though, so gonna arrange for a truck to pick it up and deliver it to the specialist.
Praying that the good sign (able to control the temperature) means it's something inocuous like a rad leak.
I had a problem with jumping temperatures - up to 120 degrees showing.
Was getting really concerned about possible problems.
No faults found with the system but the problem persisted.
Today I discovered if I switch headlights off temperature drops from 117 degrees to 85.
Switch headlights on again and it jumps back up.
Obviously an electrical problem.
Mine is an S1
Was getting really concerned about possible problems.
No faults found with the system but the problem persisted.
Today I discovered if I switch headlights off temperature drops from 117 degrees to 85.
Switch headlights on again and it jumps back up.
Obviously an electrical problem.
Mine is an S1
Oscar the Grouch said:
I had a problem with jumping temperatures - up to 120 degrees showing.
Was getting really concerned about possible problems.
No faults found with the system but the problem persisted.
Today I discovered if I switch headlights off temperature drops from 117 degrees to 85.
Switch headlights on again and it jumps back up.
Obviously an electrical problem.
Mine is an S1
that's the engine grounding issue, they all have this problem sooner or later.Was getting really concerned about possible problems.
No faults found with the system but the problem persisted.
Today I discovered if I switch headlights off temperature drops from 117 degrees to 85.
Switch headlights on again and it jumps back up.
Obviously an electrical problem.
Mine is an S1
the earth strap from the gearbox to the chassis is into a riv-nut on the chassis end, this is plated and corrodes casing this king of problem.
if you un-bolt it, clean it all up, scratch the shaped washer clean, then re-fix and apply some Vaseline (to prevent it corroding again), this should cure it.
Hi Bonehead - what was the final outcome of / solution to your problem? I have very similar symptoms...temperature shooting up as I accelerate, and dropping as i release the throttle. Had the pressure valve on the cooling tank let of several bursts of steam the other day, and thereafter the pressure in the cooling system led to a small burst close to the radiator.... the radiator has sometimes been warm during the high engine temperatures, and sometimes stone cold.
We're pretty sure it is HGF due to the various symptoms described below but just in case you found it was something else I'd love to know before shelling out several thou (i'm in switzerland - labour costs are v high) for the full HGF remedy! Thanks!!
We're pretty sure it is HGF due to the various symptoms described below but just in case you found it was something else I'd love to know before shelling out several thou (i'm in switzerland - labour costs are v high) for the full HGF remedy! Thanks!!
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