free hit
counters
No heat - Interior/Exterior/Lights/Glass/Alarms/ICE/HVAC - The Lotus Forums Jump to content
Sign in to follow this  

Recommended Posts

I just picked up a 1990 SE and it is winter (high of 25F today). There is no heat in the car, at all. I took a look in the service manual about the heater system but the pictures and explanations weren't that clear. I wasn't able to find the valve that is supposed to be located under the fusebox. Also, how do you access the area the radiator / heat exchanger and "flaps" are? Beneath the car? Would there be anything I could troubleshoot from inside?

I believe the controls are indeed functioning as I can change the "mode" and have air blow from different vents. Just can't get heat. Also, I would assume the A/C is a different system and has no effect but it is currently disconnected and the compressor isn't even fitted in the car yet. I'm hoping it something simple like a stuck valve or "flap."

Share this post


Link to post
Share on other sites

Upgrade today to remove Google ads and support TLF.

I notice your in Coastesville which is actually not to far away from me (relatively speaking). The HVAC system on our cars run off of a vacuum pump which is driven by the engine. If your not getting any heat at all I would suspect the vacuum fittings, which reside just to the right of the drivers foot well, are leaking and not actuating the heater damper. I may be completely wrong, but I would check those fittings first since they are pretty easy to find. There are a group of them all precariously connected together with T fittings. Good Luck and keep us posted!

Cheers,

Graham

Edited by Drfatz

Share this post


Link to post
Share on other sites

I'll check that stuff out some time. It's been really cold all weekend. I'd rather drive a little chilly then fool with the HVAC in the open cold with wind blowing.

Maybe we could meet up sometime, compare cars. :P

Share this post


Link to post
Share on other sites

Also note that the heat only comes out of the demister vents on the top of the binnacle(at least in my 89SE they do)

Artie


89 White Esprit SE

...a few little upgrades....

93 RX7.....Silverstone

....slightly modded...Muahaha...

New Addition:

1990 300ZX TT......Hmmm

Share this post


Link to post
Share on other sites

if your controls work then your vacuum system should be okay. I would think it has more to do with the thermocouple that goes into the core. As far as i can tell the heater core won't circulate untill it reaches temperature... so if the thermocouple is broken/malfunctioning then the valve will never open and you'll never get heat. I may be wrong about this, but there's a valve just above the top of the clutch pedal which controls the flow of fluid to the heater core, if you ensure that it's open all the time, you should get heat... There is also a possibility that the thermocouple is part of lotus' version of "climate control" which would mean that the flow of the valve is proportional to the heat setting via an electric circuit. This is far more likely. Most manufacturers just make a mechanical connection to the valve... lotus seems to have put their faith in LUCAS again.. silly buggers.

Basically... check the thermocouple -- it goes from that valve to the heater core via the top of the climate "box".


Modifying esprit's.. now that's fun..

PS... I AM NOT A CERTIFIED MECHANIC.. I Have chosen to help those in need, in the past and must not be construed as being a certified technician.

Share this post


Link to post
Share on other sites

I would locate that where Mark? Above the clutch pedal? In the cabin? Like I said, the weather is a bitter cold at the moment and I haven't been brave enough to flip upside down and check under the dash with my legs hanging out in the open cold. I'd like to know exactly where to look so I can make it quick. :P

Share this post


Link to post
Share on other sites

Well.. making it quick won't be possible -- fixing it will probably take you a while. However, it is just above the clutch pedal right against the front bulkhead. If you look at the bulkhead, you'll see a hose coming out and heading off to the left (or right if you're on your back). That leads to a brass and plastic setup that has a valve on it with a long copper wire exiting it and heading toward the heater box. The brass and plastic box is the control valve.. the copper wire goes to the thermocouple -- just like the one in a furnace.


Modifying esprit's.. now that's fun..

PS... I AM NOT A CERTIFIED MECHANIC.. I Have chosen to help those in need, in the past and must not be construed as being a certified technician.

Share this post


Link to post
Share on other sites

I have the exact same issue . . .was going to break into it this weekend, i am in NC it is around 32 F here right now. I wnt through the service manual to figure out how to work the heater controls, and it is funny. Luckily with my head 2 feet from the engine . . . i get some heat all the time . . . good luck, i will tell you if i figure anything out. I was going to check the valve first as i can hear my flaps moving when i change the knobs . . . so i think vac is ok. note that the middle vents never get heat . . . no matter how you move the contrls, it is always top or bottom from what i understand.

Share this post


Link to post
Share on other sites

Hmm, I didn't know that Chris. I'll have to investigate that a little more because I've been checking the vents in the dash cluster. If I move the mode knob (defrost to feet) that seems like it works but it blows nothing but cold air, not even lukewarm or anything.

Share this post


Link to post
Share on other sites

hello i had a demist problem, found that one of the small vac pipes had come out of an elbow. take the engine cover off get in the boot and look down near the front of the headder tank there will be a t piece coming out of the body mine had come adrift, these pipes are very small in, think ball point pen refill you can also trace these if you take out the rh side cover where the qtr glass is. hope its as simple as a pipe adrift

all the best


It's Oogies turn to boogie

Share this post


Link to post
Share on other sites

I've had this problem. Turned out the heat exchanger behind the dash was clogged.

I had to back flush it to clear out what came out as a mud like substance. Mine has worked perfectly ever since.

Share this post


Link to post
Share on other sites

If any of his hvac controls work then there's no problem with the hvac system. The system is so sensitive to leaks that nothing will work with even the smallest of leaks -- the vac pump is very weak and can only suck so much air. I am currently investigating this problem on the S4 in my shop -- if I get no leaks... it works... if i have even the slightest leak.. nothing works.


Modifying esprit's.. now that's fun..

PS... I AM NOT A CERTIFIED MECHANIC.. I Have chosen to help those in need, in the past and must not be construed as being a certified technician.

Share this post


Link to post
Share on other sites
I just picked up a 1990 SE and it is winter (high of 25F today). There is no heat in the car, at all. I

Are you sure there are no air-locks in the heater system, I think this is fairly common on the Esprit after an anti-freeze change etc....

Martyn :ermm:

Share this post


Link to post
Share on other sites

Wow... that's a really good point..


Modifying esprit's.. now that's fun..

PS... I AM NOT A CERTIFIED MECHANIC.. I Have chosen to help those in need, in the past and must not be construed as being a certified technician.

Share this post


Link to post
Share on other sites
Wow... that's a really good point..

What is your temperature gauge reading? if not 82 you have bad themostat which is why your not getting any heat. jp

Share this post


Link to post
Share on other sites

Hi,

I know you have checked but on my old S4 when I changed the radio I noticed that the outer sleeves on the cables fot the heater knobs had both come out of the clasps,meaning that although the knobs appeared to be working and indeed moved the cables a tiny bit ,they were not really doing anything . Refixed them and adjusted the travel and bingo heat.

R

Share this post


Link to post
Share on other sites

that is a good idea, my car came with some freako radio that some PO put in it . . . and it is loose, I will yank it out this weekend and look . . .

Share this post


Link to post
Share on other sites

I have some heat coming out of the screen vent but none from the footwells. I have two disconnected vacuum lines above the drivers pedals that hiss when I block them both, but I dont know where to reconnect them. There is a junction of small pipes at the end of the disconnected pipes. The Mode and Fresh air valves appear to have their vacuum lines connected, at least the parts I can see upside down with my head jammed under the footpedals! I need a diagram of the vacuum layout.

The car is a 1987 HC turbo G car.

Joolz

Share this post


Link to post
Share on other sites
Wow... that's a really good point..

what is your engine temperature gauge reading? I have seen so many people that did have any heat and all they need was a thermostat for the radiator. If it is not reading 82 change it and that will fix your heat. I can get heat to blow out from the floor, top side or dash as they all should. Just follow the direction in the manual for the correct positions of the controls. thanks jp

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Sign in to follow this  

×
×
  • Create New...