Thermostat issue? M100 runs too cold?

[Polymathic]

Now that the cooler weather has come to California, I've noticed that my temperature gauge will drop below the 1/4 mark if my driving is mellow. The engine also takes quite a bit of time to heat up. Is that an issue to worry about? Could the thermostat be stuck, and the coolant circulating at all time? (For sure, the fans only come at the 3/4 mark, only while idling in summer.) Thanks for the help.

[Fredjohn]

The readings you are describing and the behaviour of the gauge engine and fans sounds like your car is perfectly normal. There are plenty of posts on here, and probably a write up on WikiLEC to confirm this.
The only fault is the mismatch between the gauge and the temp sensor. One GM the other Isuzu, designed in as standard by Lotus!!

Don't worry, it's a Lotus.

If you are judging the engine warming up time by the gauge, this will not be accurate. Use Elanscan, this will tell you precisely the engine temp and warm up time.

[rip]

I have to disagree. It sounds like your thermostat is stuck open.
It was subtle enough for me to not notice until I was a passenger in someone else's Elan. I noticed how quickly it warmed up.
The temp gauge should sit on the 1/4 mark when driving & climb to 3/4 when idle before the fans start.

A new thermostat should not cost a lot (about £10 over here, so probably about $15). You will not lose a lot of coolant when changing it.

[steve matthews]

I have to disagree. It sounds like your thermostat is stuck open.
It was subtle enough for me to not notice until I was a passenger in someone else's Elan. I noticed how quickly it warmed up.
The temp gauge should sit on the 1/4 mark when driving & climb to 3/4 when idle before the fans start.

A new thermostat should not cost a lot (about £10 over here, so probably about $15). You will not lose a lot of coolant when changing it.

+1

[GeoffSmith]

+1

After years of diagnosing stuck thermostats from ElanScan files world-wide, I eventually realised mine was stuck open when the target idle started drifting on a cold day. It will never happen again though as I have the patented Lotus Elan temperature gauge linearised fitted.

[Polymathic]

Thanks for the information. Now is there a reference part for that thermostat part? Or are most thermostat similar? Thanks again.

*EDIT* Never mind that last question. Found all the info here. Sorry about that.

[Fredjohn]

I bow to superior analytical ability and experience

But as Geoff says, it would still help to use an Elanscan to verify and aid diagnosis.

[GeoffSmith]

But as Geoff says, it would still help to use an Elanscan to verify and aid diagnosis.

But you said it first!

[Elanlover]

.................................. It will never happen again though as I have the patented Lotus Elan temperature gauge linearised fitted.

Still waiting for the web store to open up so I can place my order Geoff!

[GeoffSmith]

.................................. It will never happen again though as I have the patented Lotus Elan temperature gauge linearised fitted.

Still waiting for the web store to open up so I can place my order Geoff!

Did you miss the group buy?

[Elanlover]

Did you miss the group buy?

Intended effect achieved.

Yes, I did nervously look at the Group Buy section before replying

[GeoffSmith]

[tigerdog]

When I first got Smaug, his thermostat was stuck open. Temp needle would dip quite far below the 1/4 mark, almost to the bottom. Once fixed, it rises quite quickly to just below the 1/4 mark and does not dip below this point again while running. If you have Elanscan, you can look at the coolant temperature from cold start to fan-on. If you see a smooth gradual warmup, the thermostat is stuck open. If you see a rapid rise, followed by a small leveling or dip, followed by more rise, then the 'stat is OK.

Best part is, at least in my case the engine runs noticeably better with some heat in it.

[Polymathic]

Thanks guys. This is all helpful. That Elanscan looks interesting, but apparently all posts on this device are very old, and I can't quite figure out if it will work on a Mac.

[rip]

Did you miss the group buy?

Completely. Can't find it in the group buy section. Has someone removed it?

[Elanlover]

Did you miss the group buy?

Completely. Can't find it in the group buy section. Has someone removed it?

ROFL.

Its the gift that never stops giving.