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Discussion Starter #1
SO I have a cooling issue in my Excel, and the traffic on the Excel related sites is so low I thought I would ask the Esprit guys.

When running the AC, the car gets hot, not overheating, but over 100C

Turn off the AC and it virtually instantly drops in temperature

IT can idle practically till it runs out of gas and it will run on the fan thermostat, 84-88C

It is not an instrument issue.

Fans run in correct direction

Thermostat changed with lower temp correct one[previous one was also correct type]

Plumbing appears correct. It might be different than Esprit. heater has a valve that shuts off flow. Funky two chamber two cap overflow/pressure tank. Heater hose sized hose feeds into bottom, small hose runs from top of thermostat to top of pressure chamber, really the same as most modern cars, but curiously Lotus.

It does not seem to gain heat at idle, I have left it idling several times with the AC running and it will sit at about 88C

Hates moving slowly under 50mph with AC on, builds temp eventually and does not want to lose it until I shut the AC off

On the highway, yesterday for instance, 88C when I got on the highway AC on, stayed virtually totally stable for 15 minute run at ~70mph
As soon as I decelerated to the off ramp, you could see the temp rise from 88 to 90, 2 stop signs wait for traffic, maybe 3-4 minutes, up to ~95C. Back on the highway, very slowly dropped until it was back to 88 in another 10 minutes or so.

Compare this to earlier in the day, I ran around town, 3 minute drive to post office, left it idling with AC on, maybe 90 C, drive in traffic temp slowly rises, open road but slow[35mph] gets to 102C, won't cool down until I shut the AC off. Mid 80sF temp.

Both radiator and condenser appear 'new' although I do not see in the records them having been changed.

I lose no coolant that I am aware of

Non contact thermometer focused on the base of thermostat housing agrees with dash gauge. Top of thermostat housing reads much cooler though, 10-15 degrees cooler which is odd to me, as on my +2 the gauge will agree with the water in the top of radiator perfectly

For all the world it feels like the fans are bad but they blow the right way, not over strong, but you can feel the suction on the grill intake
Were it a clogged radiator I feel it would get worse on the highway

ideas?
 

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Because it is impossible to properly examine the radiator for debris, and it is a common problem for them to get plugged up over time, if you have an overheat problem you should be pulling down the "Cooling System Package" to inspect and clean it. All the junk can pass through the A/C condensor coil and plug up the air side of the radiator. Then I would flush and change the anti-freeze and make sure it is properly bled. Check the hoses, if they feel soft, especially on the suction side, they should be replaced. They might be collapsing and preventing full flow of coolant. BTW, over 212 F (100 C) is not overheating, under pressure and with a 50/50 mix of water and anti-freeze, your boiling point is 256 F. Make sure nothing is obstructing the intake grill like a license plate or aftermarket lights and all of the ductwork is intact and in place. This advice is primarily for the Esprits, not so sure about Excels.
David Teitelbaum
 

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Discussion Starter #3
yeah, I know it is not overheating, but it aint right. Of course the red part of the gauge starts at 100, which is ridiculous, but makes one nervous

The air path is clear, blasted water from the radiator side to make sure there was no hidden mud. Records indicate coolant was changed twice since 2011, once by the PO's shop and once before it was imported.
 

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Wingless Wonder
1988 Esprit Turbo
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Sounds as if the air going to the radiator is being 'pre-heated' by the A/C evaporator. So, the rad (which reduces the temp by a certain amount) can't cool the antifreeze enough to get the gauge in your comfort zone.

It's been 10 years since I worked on an Elite (similar, right?) tho'.
 

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Discussion Starter #5
Yeah it is similar, if more complicated.
I expect an increase in temp, but I do not think this is normal.
 

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That water test wouldn't work on an Esprit. You can still have a lot of junk and water would pass through.
David Teitelbaum
 

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1990 Esprit SE
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blasted water from the radiator side to make sure there was no hidden mud
I agree with jtrealty. All points to a partially blocked radiator.
Try checking the temperature of the rad matrix in various places.
Areas that are blocked may feel cooler than other parts.

Andy.
 

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Discussion Starter #8
So this is the best shot I can get. Limited access to measure temps, but I see ever spot I can measure in the 80s C. You can see the condition of the radiator, and unless someone pulled it out polished it up and painted it, it is not very old. Sure it is possible that it is plugged. I personally feel it unlikely, the car is reasonably maintained, and there is no evidence of it sitting abused for any time. 60k miles, replaced AC condenser also new looking.

1268418
 

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1990 Esprit SE
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Mmmm... The rad does look new.
How about the pump. Are you happy it is circulating well.
The impeller could be corroded away or partially blocked from an earlier time.

You say its idles with the AC on, with no issue, what happens if you hold the rpm at say 1700-2000 with the car stationary and AC on?

Andy.
 

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It almost sounds electrical, meaning its voltage related to the gauge (is the temperature gauge you are looking at mechanical or electrical?) No charge (idle) with A/C on is fine, but as RPM increases with A/C on the temp (on the gauge) increases. A key statement to me was that as soon as you turn the A/C off the temp almost immediately drops (meaning the fans are now OFF and the temp goes down rapidly which is the reverse of what would normally occur) . Is it possible to temporarily install a separate mechanical temp gauge? (over and above the one in the dash) you may not have a problem at all and it could be either the gauge, sender, capillary, resistor etc etc.
 

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Discussion Starter #13
As I mentioned, it is not the instruments, I have done extensive work to stabilize voltage to the gauges. I also double checked the temp with a non contact thermometer at the thermostat housing.

Electric errors are instant, trust me, I have chased several in this project, 'almost' isn't instant
 

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Almost was my term, yours was ‘virtually instantly‘
 

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Discussion Starter #15
I was thinking of doing this


in fact bought a valve to do so

perhaps @mrdangerous has an opinion
 

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Can i ask what year excel? I've owned the Elite and Eclat but likely earlier models. Also where was its original designation (U.K, ROW?) If you haven't done so i would also recommend you post the question on the S1/S2/S3 group and Turboesprit forums as several of those members currently own Excels, Elites and Eclats, as well as the earlier Esprit. Tim Engel owns an Eclat i believe, he would be my best best.
Can be found here:
 

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Wingless Wonder
1988 Esprit Turbo
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"Professor Tim" is @Esprit2 here. He is on FB too.
 

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Discussion Starter #19
So I ran a bypass around the heater today. I have a bypass valve on order, but I do not foresee needing the heat the next 2 weeks, so I will see how it goes. Of course it is 69 degrees the next couple days, so hard to test.
I did drive it around today, both with and without the AC on. Max temp about 91 degrees, AC on. Mostly 81-86. Seemed more stable, but it is not warm enough to make a real judgement
 

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Discussion Starter #20
Warmer today, drove inland to where it was 84F outside. It did get hotter than I think it should, but it seems to act more rationally. It still struggles to come down from high temp when I think it should.
For instance deliberately drove into traffic, multiple traffic lights, slow going. It got up to about 100C, and when I got on the highway, I would 'expect' it to drop fairly quickly down, but it really several minutes for the needle to start dropping. Mind you I was deliberately heat soaking the car

Still odd that it loves to idle. Pull into a parking spot and it will slowly cool down, rather than the reverse.
 
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