Thermostat Problem?

[DAdragna]

I noticed that my engine temp gauge does not climb above the first mark on the bottom of the temp gauge when moving. If the car is left to idle, the gauge will climb only slightly, never to the level where the fans would come on. I notice when stopped for a brief period of time the heat gets nice and warm...then once moving again the car engine temp gets cool and the heat becomes luke warm? Is this symptom of a stuck thermostat?

On another note, the car's boost reaches .5 bar and will not go higher.
(I have not checked into the TPS sensor yet because I think the lack in boost may be relative to the temp issue.) I believe that the mechanical boost will deliver .5Bar, and the additional is from the frequency valve. On my old Esprit, the frequency valve that pulses to control additional boost would not cycle because the car was running to cool (Therm prob).
Any thoughts or suggestions would be appreciated!


PS-I have had the car one day and love it! (Also put 1350 miles on it!)
What is the correct therm for the car. Isuzu? Part?

Dan A

[Doc Fizzix]

This sounds about right, my mark rarely goes above the first mark, also, boost is origanaly set to .65 bar.

The heating problem could be that the valve for the heater is not operating correctly. it is vaccum controlled and can lock up if it hasrusted upor may not be getting vaccum.

When the thermostat goes out, it usually sticks closed so the car runs hot.

[Gary]

That all sounds normal to me. Boost about half way on the gauge and temp gauge sits at bottom under normal conditions.

I would expect the temp gauge to go up to 3/4 if left idling for a long period and then for the cooling fans to kick in. If this doesn't happen then something is amiss

[chris.t]

i have been told that the in cabin gauges are not necessarily that reliable so (not that i've tried cos i'm laptopless) elanscan might give some clues??

[ab2cv]

I noticed that my engine temp gauge does not climb above the first mark on the bottom of the temp gauge when moving. If the car is left to idle, the gauge will climb only slightly, never to the level where the fans would come on. I notice when stopped for a brief period of time the heat gets nice and warm...then once moving again the car engine temp gets cool and the heat becomes luke warm? Is this symptom of a stuck thermostat?
Dan A

Mine behaves in exactly the same way and I've been meaning to post the exact same question now for a while. My car is taking longer than ever to heat up and I can be driving for 30 mins before the air through the vents even begins to get warm - it never used to take this long.

I guess that the thermostat is a relatively cheap component to replace anyway to eliminate it from the equation(?)

Alan

[DAdragna]

When I said the first mark on the gauge, I don't think I was clear.
I mean the bottom mark at the cold point. I found some talk in another area on the list where they discussed this same problem. The heat works if you let the car sit and idle for 10 minutes. When you drive the car the heat turns luke warm at best. So...I am sure all heater components are fine..just lacking good hot water because the thermostat is either stuck open or just opening too soon. I will put one in in the next couple of days and post my results.

BTW-When I got my first Esprit, I always would wander out into the garage for no particular reason..just to look at it. Then I got my second Esprit...and would do the same. Well, I am back to wandering out into the garage to just look at the Elan...and my garage never looked prettier!

Thanks,
Dan

[ab2cv]

Concur entirely with you on the gauge needle position - mine appears to not even move from the bottom stop pin (or whatever you call it). I'd be extremely interested to hear if changing the thermostat makes a difference.

Alan

[Gary]

On my S2 the needs rests right on the bottom, on my SE it goes up to quarter. Neither does much in the way of producing any heat from the heater

[Dico]

BTW-When I got my first Esprit, I always would wander out into the garage for no particular reason..just to look at it.

Nothing unusual about that

The missus wonders why i volunteer to take the washing out to the dryer so often

[Doug]

I had the same issue for some time--the temp would go to the bottom peg when moving and the cold idle setting would even come on again then. Sitting it would warm up a bit -- turned out to be a sticking t-stat cured by replacing it. Problem was it would stick open like that but one day it stuck closed and barely got the car home without blowing it up.

So be warned and change the t-stat if it is sittin on the bottom mark -- this is not normal!!!

If you hook up ElanScan you should be able to tell that it really is running too cold on the CTS, etc.

see: http://lotuselancentral.com/lec/thermostat.htm

[Gary]

I don't want to get in an argument with Doug, but my mechanic reckons it is perfectly normal for an Elan temp gauge to sit at the bottom

[Paul.P]

I don't want to get in an argument with Doug, but my mechanic reckons it is perfectly normal for an Elan temp gauge to sit at the bottom

Dito !

[M100 TWO]

It is for sure a stuck thermostat ,or the rubber seat that has deformed parsing water,which was what happened to me, the gauge should read one stop under half way

[John_W]

This Elanscan plot shows how the temperature should rise when sitting at idle for a long period.
http://www.asnu59.dsl.pipex.com/elan/gr ... p_idle.jpg
You can see the thermostat opening then the fans cutting in.
John

[Doug]

I don't want to get in an argument with Doug, but my mechanic reckons it is perfectly normal for an Elan temp gauge to sit at the bottom

well, it depends on your gauge. The bottom line is to see what the true temp is and that requires ElanScan! If the coolant temp is below your thermostat opening temp and the car is warm, then the t-stat is stuck open!!

The gauge could be operating properly and fine at the bottom, but otherwise, most gauges are designed to not sit at the bottom peg when running at operating temps . . . this defeats the purpose of the gauge. Since the Elan's gauges are not high end it may just be that some read low normally.

[DAdragna]

I agree with the don't fix what isn't broke theory whole heartedly. But.....
I noticed issues with my heat that could only be explained by thermostat irregularities. (Based on it's behavior) The thing that surprises me with regards to the temp is that I know for a fact that on the Esprit the frequency valve that purges pressure to the wastegate capsule is controlled by the ECU based on engine temp / intake temp / fuel mixture. The frequency valve allows slight overboost. The Esprit SE uses .65 approx as the mechanical boost setting, the frequency valve (under acceptable conditions / with TPS wide open) will pulse and allow overboost to .8 approximately. I believe that the Elan uses the same technology only the numbers are different .5 and .65. (I am not sure...haven't started reading the manuals yet-or really looked over the motor)

Now here is what I am thinking... My car gets .5 on the gauge under full throttle conditions. I know that the gauges aren't that accurate all the time but I have a feeling mine is on the money! I think after I put a new thermostat in the car...I will see .65 on the gauge. My old Esprit would not get the full boost (wide open throttle) and I did everything everbody was telling me. (replaced TPS, rebuilt chargecooler pump, had turbo machined with hybrid compressor wheel, the list goes on) Then one day somebody asked me what temp my car was showing on the gauge. I also checked the temp using my laptop and freescan (like Elan scan). Well it turns out that the car was not fully warming up. I put a proper thermostat in the car and warmed it up and guess what!? Full boost! I guess that the ECU will only pulse the Frequency valve if the car is a certain temp!

If this makes no sense and what I said about the Elan using similar tech as the Esprit is not correct...I am sorry I was justing talking out of my ass.
But if what I said is correct...I may be onto somthing.

I am going to get a thermostat right now!

Cheers,
Dan A
99 Esprit V8
92 Elan

[ESM]

I agree with Doug's post - its normal for the gauge to sit at the first mark on the temp scale its NOT normal for it to sit on the peg.

DAdragna you are quite right, active boost control is enabled only once the engine is warm (from memory a cololant temp around 60-70°C) and disabled again when if its too hot (again from memory 100°C). My experience is that passive boost is around the 0.5bar mark, although the manual says its 0.4bar.

The coolant temperature sensor and the gauge sender are discrete units (like the boost gauge sender and the MAP sensor) so its quite possible for the temperature gauge to be dead without any engine management consequences. If the boost is low and the gauge reads low then the thermostat may well be at fault. Another possibility if boost and temp readings are low is that the earth to the thermostat housing is bad, messing up both temp. sensors' readings.

[Monty]

I agree with doug to, if the garage says thats normal then he is a clown and u need to change garages .

Make sure the temp gauge is working IIRC just earth the wire on the needle should move changing the thermostat is the next thing and an easy job to do. Also try earthing the thermal fan switch to make sure u`r fans are working.

U could be right on the boost side as when the engine is cold i`ve also noticed the boost is restricted to 0.5 bar

[Doug]

I agree with the don't fix what isn't broke theory whole heartedly. But.....
I noticed issues with my heat that could only be explained by thermostat irregularities. (Based on it's behavior) The thing that surprises me with regards to the temp is that I know for a fact that on the Esprit the frequency valve that purges pressure to the wastegate capsule is controlled by the ECU based on engine temp / intake temp / fuel mixture. The frequency valve allows slight overboost. The Esprit SE uses .65 approx as the mechanical boost setting, the frequency valve (under acceptable conditions / with TPS wide open) will pulse and allow overboost to .8 approximately. I believe that the Elan uses the same technology only the numbers are different .5 and .65. (I am not sure...haven't started reading the manuals yet-or really looked over the motor)

Now here is what I am thinking... My car gets .5 on the gauge under full throttle conditions. I know that the gauges aren't that accurate all the time but I have a feeling mine is on the money! I think after I put a new thermostat in the car...I will see .65 on the gauge. My old Esprit would not get the full boost (wide open throttle) and I did everything everbody was telling me. (replaced TPS, rebuilt chargecooler pump, had turbo machined with hybrid compressor wheel, the list goes on) Then one day somebody asked me what temp my car was showing on the gauge. I also checked the temp using my laptop and freescan (like Elan scan). Well it turns out that the car was not fully warming up. I put a proper thermostat in the car and warmed it up and guess what!? Full boost! I guess that the ECU will only pulse the Frequency valve if the car is a certain temp!

If this makes no sense and what I said about the Elan using similar tech as the Esprit is not correct...I am sorry I was justing talking out of my ass.
But if what I said is correct...I may be onto somthing.

I am going to get a thermostat right now!

Cheers,
Dan A
99 Esprit V8
92 Elan

exactly, I agree with your info and reasoning fully -- replace the t-stat and your gauge should read temp at the first hash mark, the coolant should warm properly, nd you will get full boost.

drop in the ESM chip and you will get some sick boosting fun . . .

[DAdragna]

Doug,

I replaced the Thermostat last night with a 90C. I performed a little test before doing so. I let the car idle for 30 minutes...fans did not turn on..and the temp guage rose only slightly. After the new thermostat was installed, the temp indicator went to the middle of the cold and hot range.
Every few minutes the indicator would go about 3/4's and the fans would cycle. Haven't driven it yet, it was pouring rain last night. I am curious to see what the boost will do?

BTW-I had read another thread where M100 had commented on adding a chip and it not working well with out a MBC. He had also commented that his car had similar behavior as mine, temp wise. It seems the chip would add fuel (running rich) but not be able to increase boost via frequency valve unless the car is the correct operating temp. This would explain the car not running well with the chip. Right? Not knocking anyone, just inquiring!

Dan A