2002 saturn sl1...last night, i was in the car for about 45 minutes and realized that even though i have the heat on full blast, it only comfortable in the car...normally, it's on high for 5 minutes and it's ridiculously hot and i have to turn it on

checked the air and sure enough, it's only blowing out barely-warm air, despite the fact that it was on max heat

what's broke and what's it going to cost me to fix it?

12/7/2009 8:27:39 AM

Very first thing...check your coolant level. Low coolant levels are notorious for producing that very symptom.

If it ain't that, then your heater core may be plugged up with scale. I've successfully backflushed heater cores before, and it's worth trying in light of the fact that the heater core is also notoriously difficult to get to in most cars. If there's permanently rooted scale in there, the symptoms would have had a much more gradual onset, though. I'm thinking the problem lies elsewhere, such as a malfunctioning air mix door or a stuck thermostat in the engine. Is your temperature gauge coming up to normal operating range?

12/7/2009 8:51:18 AM

Try switching the controls to cold for a minute and then back to heat. (is that car vaccum or cable controlled? I would usually assume cable w/ saturn)

Check the passenger side floor-board. any signs of moisture?

I agree with what zxappeal said. its probably engine related, not something inside the cabin.

Dont get overly concerned about it, heaters are very SIMPLE and it is most likely a easy fix.

12/7/2009 9:10:41 AM

My 98 saturn sc1 beater has just done the same thing, i'm banking on the t-stat so I will report back when I get it changed out.

12/7/2009 12:40:05 PM

Quote :

"Very first thing...check your coolant level. Low coolant levels are notorious for producing that very symptom."

well, coolant was definitely low, just barely below the minimum line...i topped it off, but that coolant is NASTY...brown and there is some powdery dark gray deposits in there...i assume it desperately needs to be flushed?

i can't tell if it made any difference or not...even after a good 10 minutes of driving/warm-up, the air remains fairly cool...when i'm driving, though, it warms up a bit (warmer than before, but still not nearly as hot as it used to be...not even close)

Quote :

"If it ain't that, then your heater core may be plugged up with scale. I've successfully backflushed heater cores before, and it's worth trying in light of the fact that the heater core is also notoriously difficult to get to in most cars."

how hard/expensive is this?

Quote :

"If there's permanently rooted scale in there, the symptoms would have had a much more gradual onset, though."

you know, i really don't drive my car that much considering i scooter everywhere...and when i do, it's usually just around town...over the past few months, it's been warm enough that i doubt i've used it very much, so maybe it WAS gradual

Quote :

"Is your temperature gauge coming up to normal operating range?"

it seems to be...this past summer, i was caught on 40 one night that they were doing construction and sitting in traffic...the car started to overheat pretty quickly (bad ECM or whatever it's called that controls the fan, i assume)...i never did get that fixed, but that's because it hasn't been an issue recently

*shrug*

Quote :

"Check the passenger side floor-board. any signs of moisture?"

i don't think so...but it's strange that you mention the passenger door, since the door has been sticking something fierce over the past couple of weeks...never had this trouble before, and i can't figure out why it's sticking...

12/8/2009 10:14:45 PM

suggestions?

12/9/2009 5:35:18 PM

I'm guessing since adding coolant did nothing you still have an air bubble in the system or your heater core is indeed plugged as zx said earlier. Do you hear swishing/gurgling water when you start up the car or when you start to drive? There's likely an air bubble. I'd get zx or the other garage guys here to go ahead and backflush it (cheapest option right now to find out for sure) because all that nasty shit you saw in the coolant tank/radiator is back in those dozens of little tubes going through your heater core. The other thing is, that chocolate mousse-looking gunk you have can be caused by just old coolant , or oil mixing with the coolant and vice versa. Overheating an older engine can crush the gaskets by thermal expansion and eventually the weakened gaskets can blow or crack leading to coolant loss, clogged heater core, worse gas mileage, and a slew of bad juju.

12/9/2009 6:27:00 PM

huh. i always thought cars just pulled heat straight from the engine... is that a common misconception?

should i turn on the "AC" switch when I run the heat?

12/9/2009 6:49:58 PM

Quote :

"it seems to be...this past summer, i was caught on 40 one night that they were doing construction and sitting in traffic...the car started to overheat pretty quickly"

This bit could be a thermostat problem.

12/9/2009 8:06:56 PM

Quote :

"huh. i always thought cars just pulled heat straight from the engine... is that a common misconception?"

depends on what you mean by "pull".. i mean, it's coming from the water that's going through the engine. i guess you figured that out already now though. heater core = small radiator inside the car basically.

[Edited on December 9, 2009 at 8:24 PM. Reason : but nah, never knew anyone messed that up ]

12/9/2009 8:23:31 PM

If it was still in the reservoir, just below the "low" line, odds are adding isn't and didn't do anything.

I would try back flushing it first. This is not hard to do, nor is it time-consuming. When doing this, you are 75% of the way to a "coolant flush" so you might as well finish the job.

If you drive around normally and it doesn't over heat, but when sitting in traffic (even for short periods of time) it does, than you are probably correct to assume that the cooling fan is not coming on. Usually the PCM controls it, but odds are that isn't the problem. There are multiple re-lays and speed control devices in between that usually go bad. Also, the fans have 2 purposes: for the a/c system and for engine cooling (although they are in the same spot). Usually turning the a/c on will force at least one of the fans to come on. Next time you see it start to overheat, try that to see if it stops.

It could also be a bad or sticking thermostat, but then the car would either take FOREVER to get up to normal temp in the mornings, or would very rapidly start to overheat. How long does it take for your car to warm up? Does turning on the heat slow this process down?

Depending on how hot you let the car get sitting in traffic, you may have messed up the headgasket. Basically what Chief said. this is BAD. hope this isn't the case. How long were you in traffic, how hot did it get, how long did it stay there, ect??

I'm not sure what you mean by passenger door. I wasn't necessarily taking about the door you use to get in and out of the car. If that door is hard to open it could be the fender is dislodged, the hinges are getting worn, needs grease, ect. Just check to see where the noise is coming from or where it is difficult (all the way closed usually means a latch problem, or halfway means a hinge problem)

What I was asking is to see if your heater core was leaking into your car. If that was the case, usually the passenger front floor (underneath the glove box) gets moist/wet.

12/10/2009 11:28:40 AM

bttt

4/9/2010 10:42:26 AM

last night it started to overheat again while sitting in traffic

4/9/2010 10:44:44 AM

Check that that radiator is full(check it cold, it will explode on you if you open it hot) Check the fluid level in the radiator itself, not the plastic bottle. Fluid should have at least some antifreeze in it, don't run straight water. Crank it and let it start to overheat. Is the radiator fan coming on with the A/C off? (the A/C should turn the fan on automatically) Look for steam leaks. Are both upper and lower radiator hoses hot?

Don't let it overheat, you'll blow the head gasket or worse.

4/9/2010 10:50:34 AM

radiator level's good (cold)...it's 50/50 water/antifreeze

i'll check the fan when i get home (i didn't drive it today)...i was thinking it might be the ECM

it's only actually gotten into the red that one time that i posted about above...fortunately i was paying attention to my gauges last night and saw it creeping up (99% of the time the needle hovers just barely past the 1/4 mark...it's always been like this...last night it crept to past the 1/2 mark...red happens at 3/4 mark on the gauge)

4/9/2010 11:00:28 AM

thermostat might not be opening

[Edited on April 9, 2010 at 11:50 AM. Reason : actually, i doubt it's that given the description. check out the fan.]

4/9/2010 11:50:15 AM

i didn't have a chance to let it overheat, but i did turn it on

whether the AC was on or not, the fan did not turn on...should it only come on once the car heats up? or should the fan ALWAYS come on if the AC's being used?

4/9/2010 12:47:38 PM

Usually the fan turns on whenever the AC is on, though I'm not sure if that's a rule of thumb for all cars.

If it is the fan you're in luck b/c that's one of the cheaper fixes given your problem. When you have time try to get the engine to come close to overheating and if the fan absolutely doesn't turn on then that could very well be your problem.

4/9/2010 3:34:59 PM

^ likely being the ECM or the fan itself? or the thermostat?

4/9/2010 3:41:14 PM

If the fan doesn't come on it could be the ECM or the fan motor itself. Doubtful it is the thermostat. I had the ECM short out for my old Accord's cooling fan way back in the day after I drove through a huge puddle at speed. Didn't realize it till a few days later when it almost overheated

4/9/2010 4:02:36 PM

fan doesn't cut on on at all...i didn't let it get all the way to overheat, but i watched it until it began its inevitable creep past normal operating temp and checked the fan...never cut on

is the ECM generally pretty easy to replace? kind of like a fuse?

4/12/2010 8:58:07 AM

swapped out the cooler fan relay and no dice...checked the 30-amp fuse and it's fine...so i assume i have a bad fan

how hard are they to replace? it LOOKS pretty easy...

4/15/2010 5:44:46 PM

put 12 volts across it and then you'll know if it's bad

4/15/2010 5:46:49 PM

Shouldn't be too hard to replace. I suggest picking up a used one from the junkyard.

4/16/2010 10:34:46 AM

the ecm going bad and causing the fan to not work is pretty common, from what i understand. happened to a friend of mine on her saturn.

4/16/2010 10:54:39 AM

the ECM is $550 at advance

i don't care about my car THAT much...then again, if i have no other choice...

4/16/2010 12:43:25 PM

You can wire up the fan to a switch or a shove the wire in a fuse that only comes on when the key is on, or splice it in to the headlights.

But before you go rigging it, check that fan relay is getting the on signal from the computer. Also check for blown fusible links.

4/16/2010 1:01:45 PM

try a junkyard.
wagners, lkq, etc

4/16/2010 1:16:29 PM

Quote :

"But before you go rigging it, check that fan relay is getting the on signal from the computer. Also check for blown fusible links."

how would i do this? i replaced the relay, so the relay likely isn't bad, but i'm not quite sure how to tell if the relay itself is getting a signal...also, fusible links? i checked the fuse associated with the cooling fan and it's fine, as are all of the other fuses in the same fuse box (mostly 30-amp fuses)...not sure what else to check, there

stupid question - could i not just take the fan wires and hook them up directly to the battery?

4/16/2010 1:19:30 PM

+12v across 85 and 86 for the signal - if not, i would suspect the ecm

you should also have +12v at either 87 or 30
one is the actual power that gets delivered to the fan, the other runs from the relay to the fan motor - if not, check for another fuse in the system

if you need a hand let me know.

[Edited on April 16, 2010 at 1:26 PM. Reason : clarity]

4/16/2010 1:22:51 PM

Quote :

"stupid question - could i not just take the fan wires and hook them up directly to the battery?"

yeah, you can, but then the fan is gonna run all the time, even when the car is off

i was saying to do that to check if the fan motor is bad

[Edited on April 16, 2010 at 1:26 PM. Reason : ed]

4/16/2010 1:25:58 PM

^ you could wire it up such that there is a manual switch, or even wire in a relay so that the fan runs when the car is running. but both are kinda ghetto.

4/16/2010 1:27:17 PM

uhm

[Edited on April 16, 2010 at 1:27 PM. Reason : wtf double post]

4/16/2010 1:27:17 PM

^^ what do i use to test it, though?

^ i meant only to test the fan

4/16/2010 1:28:04 PM

multimeter or a test light. i have a multimeter you can borrow if you need to.

[Edited on April 16, 2010 at 2:20 PM. Reason : it's extremely simple]

4/16/2010 2:19:58 PM

test for voltage at the plug that connects to the fan motor

4/16/2010 2:38:08 PM