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HELP: K-series S2 overheats when idle, A/C doesn't blow cold air

2K views 18 replies 6 participants last post by  eliseS2 
#1 · (Edited)
My S2 K-Series Lotus overheats when idle (only when idle and VERY fast) and A/C doesn't blow cold air.

The car has been in the garage for 2.5 years after which I replaced both radiators and fans (with OEM parts). It was perfectly fine before it was garaged.

We have so far:
- bled the air from the radiators multiple times
- checked for leaks (no leaks at all)
- checked thermostat
- checked water pump
- ran CO2 test to check HGF
- checked ****load of evident small things that could be the culprit and no luck so far

They say the A/C pipes are freezing cold, but the heater control doesn't correctly distribute the heat (or the air? or whatever) which they say may be why the A/C doesn't blow the air. They also say the issue with the heater control may be the reason why the whole cooling system doesn't work. Or that some pipes are messed up and they need to take the whole cooling system apart.

They also say that it's likely the heater cannot be repaired partially and needs to be replaced completely which may or may not solve the issue. Anyone knows how much is the heater for 111s?

Any suggestions please?
 
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#4 ·
So you could drive for an hour as long as you don't idle and it won't overheat?

When you say overheat, is it dramatically boiling or is the gauge reading high?

take the front wheel arch covers off and feel the radiator hoses to see if they are both hot. If not, there is no coolant flow

Try the AC from dead cold and see if there is something approaching cold air, if so it must be the flap is not moving, otherwise there are a whole bunch of things there that could be wrong.
 
#5 ·
Correct, I can drive for hours and it won't heat up, but as soon as I stop it goes up by 1 degree celsius per second. From 94 to 107 in a matter of seconds and it doesn't stop rising so the longer it's idle (in seconds, not minutes) the higher the temperature.
 
#7 ·
It heats up THAT fast, I am not exaggerating. I stop at the traffic light and I have to shut down the car because it heats up from 90smth to over 105 degrees before the light turns green.

It's extremely unlikely there is any air left because they bled it multiple times already with the vacuum filler.
 
#9 ·
I know its on your (I tested ) list but I had that same thing on my mr2. Turned out to be an air bubble in my coolant system. Had that exact same symptoms even the AC issue. Mr2 had many bead valves.

running my AC blower at %100 slowed down the heating.
 
#10 ·
I don't think they've done the compression test, but based on the CO2 test and some other test, HGF is pretty much out of question. It's probable the A/C and overheating issue is connected because something's not right with the cooling system, not the engine itself.
 
#12 ·
Just as a sideways bizarro comparison:

my Xterra for some reason never draws coolant out of the reservoir

give me no problem

except.....

no heat at idle

works perfect at speed

so air gets in it and won't let if flow, pump faster and it splashes through

I refill directly to the radiator and it is fine, because it self bleeds

Elise does not self bleed so well

just sayin..........
 
#15 · (Edited)
This really sounds like trapped air or an above-coolant air leak where the system won't pressurize, but it also won't leak much. The fast temp rise sounds like steam as exigegus pointed out.

The leak check was done with a pressure tester I presume?
So the system held pressure at x bar for xx minutes?
Even with an airlift, there can still be air pockets on this car. I'm not sure how this happens.

Since you replaced the fans, are they blowing the correct direction? At speeds above 35 mph, you don't need fans at all, so the fact that it gets warm when stopped makes me think that the fans aren't running, or they are possibly running in the wrong direction.

The CO2 HG test only checks for compression-side HG failures. If there is a non-compression HG leak, you won't pick it up that way. I'm doubtful that you have a HG leak, however.
 
#16 ·
Yes, they did the pressure check. Fans are blowing too. They still cannot find the issue, though. Everyone I talk to keeps telling me it's an air pocket, but we've checked it a million times and I had the radiator replaced in the past without any issues. Madness...
 
#19 ·
Alright, so we have finally managed to solve the issue. It looks like the A/C and overheating was not connected after all. A/C didn't work because of some issues with the heater. Overheating was mostly due to the electric pump which was terribly malfunctioning. Since they don't have the right software to properly read old Rover engines (nobody here does, literally), they said it might take a long time to figure out exactly why it doesn't work properly, and since I don't really need it, they completely turned the electric pump off (not to be confused with the water pump). They also replaced the intake manifold gasket, almost completely took apart the cooling system looking for signs of corrosion or similar.
 
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