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-   -   02 sl1 heat isn't working (http://www.saturnfans.com/forums/showthread.php?t=232999)

Thruxtonup 11-09-2017 05:59 PM

02 sl1 heat isn't working
 
Hey all, just recently found the forum.
I have an auto 02 sl1 with 105xxx miles.
I've ran into a strange issue where, it's throwing a constant coolant temp light, no matter where the temp gauge is and will only blow warmish air on the lowest fan setting. Any higher and the air is pretty much the ambient temperature.
Any insight is appreciated!

Chrisohki 11-09-2017 06:37 PM

Re: 02 sl1 heat isn't working
 
Have you checked your coolant level yet?

Thruxtonup 11-09-2017 06:38 PM

Re: 02 sl1 heat isn't working
 
Yes. Completely full

Chrisohki 11-09-2017 07:29 PM

Re: 02 sl1 heat isn't working
 
Could be the thermostat stuck in open position.

How hot does the gauge get after rubbing for 15/20 mins?

Thruxtonup 11-09-2017 07:42 PM

Re: 02 sl1 heat isn't working
 
Usually hangs on between 1/4 And 1/2

fdryer 11-09-2017 08:13 PM

Re: 02 sl1 heat isn't working
 
You may be describing two issues; lack of heat and an errant coolant indicator. If the engine isn't overheating, the coolant indicator may be telling you coolant level is low. Even when coolant level is correct, old cooling systems create slime and other undesirables. I not flushed out and replacing antifreeze, sludge may collect on the float, dropping it lower by weight and triggering the coolant light. A quick test of this is to overfill the container above the fill line by about an inch and see if the light turns off. If it does, the coolant container can be cleaned with hot water and dishwashing powder to remove sludge on the float. Or just overfill and leave it at that. The lack of heat may be related to one of several things; blocked heater core, heater hoses, outlet tube or worn out t-stat. If periodic coolant flushing and replacement isn't done, do so and disconnect the heater hoses to force water into the heater core to flush out any blockage, reversing flow to ensure flow.

T. Thudpucker 11-11-2017 12:20 AM

Re: 02 sl1 heat isn't working
 
I'll cast my vote for blocked heater core.

trottida 11-11-2017 07:21 AM

Re: 02 sl1 heat isn't working
 
1 Attachment(s)
The SOHC engine doesn't create much heat to begin with even at full operating temperatures.

The first problem regarding the low coolant is likely a stuck float switch in the coolant reservoir as fdryer noted.

The second issue could be a few things...
[LIST][*]A bad ETCS which are cheap and easy to replace.[*]A failed thermostat which again are cheap but a bit more involved to replace.[*]A blocked heater core which sometimes you can back flush to resolve.[*]The HVAC temp controls could be failing (not likely).[/LIST]
If you've never changed the thermostat I'd probably start there and while you have the coolant drained I would back flush the heater core and clean up that reservoir. It wouldn't hurt to change the ETCS even though in the 2002 models they installed the brass tipped version which don't crack like the resin tipped versions installed prior to 2002.

Edit: I just noticed that you wrote "Coolant Temp Light". We both assumed low coolant light. Which one of the two shown below are you referring to? The temp gauge and the coolant temp warning light would both be controlled by the ECTS. Try changing this first.

[IMG]http://www.saturnfans.com/forums/attachment.php?attachmentid=51694&d=1510403671[/IMG]

trottida 11-11-2017 07:49 AM

Re: 02 sl1 heat isn't working
 
Also, the temp gauge should read as the gauge below (~1/3) if your ETCS and thermostat are working properly. If fully warmed and it hangs at 1/4 it is likely you have a leaking thermostat which is not allowing the engine to come up to temperature and thus not providing sufficient heat to the heater core.

[IMG]https://mike-thomson.com/blog/wp-content/uploads/2012/07/temp-gauge-3-8.jpg[/IMG]

Thruxtonup 11-16-2017 03:29 PM

Re: 02 sl1 heat isn't working
 
[QUOTE=trottida;2258958]Also, the temp gauge should read as the gauge below (~1/3) if your ETCS and thermostat are working properly. If fully warmed and it hangs at 1/4 it is likely you have a leaking thermostat which is not allowing the engine to come up to temperature and thus not providing sufficient heat to the heater core.

[IMG]https://mike-thomson.com/blog/wp-content/uploads/2012/07/temp-gauge-3-8.jpg[/IMG][/QUOTE]

I'm sitting in it right now, the coolant is up to temp but it's not blowing any warm air at all. So I'm going to wager it's the core. I'll try to back flush it tomorrow

alordofchaos 11-16-2017 03:55 PM

Re: 02 sl1 heat isn't working
 
Two more possibilities are the blend door and the temperature slider.

The temp slider has a cone shaped arm at the other end that a wire loop cable end to the blend door hooks onto. I was getting no heat in the cabin because the previous owner disconnected it for some unknown reason (when installing a stereo?). If you are the original owner, or the heat worked before but stopped, this is probably not the issue - the cone has a groove that the end loop locks into and is unlikely to slip out.

The cable moves a blend door which controls how much heated air enters the cabin. occasionally, the gear or something breaks and the door does not move.

With the light, assuming it's the Engine Temp Light (on solid, not blinking) and not Low Coolant, I believe it can trigger if there is a fault or temperature mismatch with the automatic transmission coolant temperature sensor, located at the top of the trans. I don't have an owner's manual handy or an auto trans- maybe someone can confirm.

edit: to take a look behind the radio, I followed this, skipped all the steps noted, but also skipped the second step (column filler panel)
[url]http://www.differentracing.com/tech_articles/00-02radio.html[/url]

You may be able to check the core for blockage by checking temp of the inlet and outlet hoses. Of course, if your coolant is old or unknown age, may as well flush the crap out of everything :)

RobertGary1 11-16-2017 05:38 PM

Re: 02 sl1 heat isn't working
 
I had a heat issue that was caused by an anchor on the sleeve for the heat control breaking free and allowing excessive flex on the sleeve. As a result I lost about 75% of cable movement. The attach point is just to the right of the driver's right leg. Just remove the panel and make sure the cable sleeve is still attached to the air box and not moving around when you move the heat control.

-Robert

Waiex191 11-16-2017 06:56 PM

Re: 02 sl1 heat isn't working
 
I have no contribution, but a heat related question. The floor heat on my SL2 has been weak since new. Is this typical? My old 83 Omni was junk, but the heat on the feet was awesome.


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