Stupid Saturn Heater

[wahoowad]

We have a little 4-banger Saturn, maybe 2001 or 2003 year. She normally drives it but lately I have been driving it. The heat sucks. It takes me 25 minutes to drive to work and the air coming out the heater is still lukewarm after all that time. My truck has nice, warm air after just a couple miles.

My initial thought is that maybe the thermostat is stuck open on this car. I've heard an open thermostat allows the coolant to pass continually and not let the engine temps warm up like usual. Any way to check the thermostat without cracking open the system and having to replace the gasket and lost coolant? Any ideas on what else it could be? All the heater controls appear to be working.

 

[wahoowad]

Funny answer from a guy with a name like bondo. Anyway, so...thinking...if the heater core is plugged then I might be able to feel a significant temp difference between the radiator hose and the heater core hose? Just want to check as much as I can before tearing stuff apart.

 

[Highbeam]

Is your temp gauge coming up on the dash? It's easy peasy to change the stat on most 4 bangers and the coolant doesn't last forever. You probably have like 3 quarts of coolant in that engine so it isn't a big deal to replace the cheap t-stat. Having heat is just so important.

 

[Danno77]

you're right, it sounds like a stuck open thermostat. wayyyy better than stuck closed. Try this to see if it helps: get some cardboard and put it in front of the radiator and see if that helps. if it does then that's probably the problem. won't hurt too badly to wait until warmer weather to take care of it, so if the cardboard works then you could get by. is there a temp gauge on the dash?

i have experience with three vehicles and only one has a helpful gauge. The aerio has dummy lights = blue is too cold, red is too hot, no light means either broken or ok temperature. The honda says "Hot" at one end and "cold" at the other, with absolutely NO indication of where the needle should rest or what the hot temp is or the cold temp. The jeep has a gauge that says 100 at the low end, a little line at where it should reside, 210 in the middle and then some temp at the high end.

 

[EatenByLimestone]

When I change a thermostat I usually go for a quality one. I like RobertShaw. They operate off the expansion of a ball of wax instead of bimetallic strip. They used to be lifetime guaranteed.

Matt

 

[mayhem]

If its a GM product and the coolant has never been changed, its probably got the dreaded DexCool in there, GM's 100,000 mile coolant. It has a tendency to create silt while its in there and hat silt gets caught up in the heater core and plugs it up. If your hester core hoses are different temps, you've probably got a plugged core. Take both hoses oss and run a garden hose through the core in both directions until the water coming out is clean. Plug the hoses back in, top off the coolant and start her up...you'll still have air in there, so you'll have to run it and burp it a bit to get it filled properly. If you ge a plug of crap that looks like coffee grounds coming out of there you ought to flush and fill the whole system eventually because the radiator is probably full of silt too and is not working as efficiently as it should.

If both core hoses are hot (like you can't hold it in yuor hand fr more than a few seconds hot) then your core is fine and you can do the T-stat.

Only other thing I cna think of if that all checks out is a temperature blend door stuck on cold.

 

[billb3]

You could try disassociate the heater core from the cooling system and see if water from a garden hose will pass through it to test for blockage.
For the T-stat there's always boiling it in hot water to see if it opens - most meat thermometers will take ya to 195 degrees aroundabout where t-stats should be open. Course if it's stuck open boiling it won't do much.

The flap/door at the other end of the temp adjuster may not be doing anything if there is one.

I had a Sentra with the air /door / cable not working problem. Heat was on medium all the time.
It got fixed real quick on a trip to Florida one January. Luckily the end of the cable had just popped out.

 

[Flammam]

I own 5 saturn S series cars. Flush your cooling system and change your thermostat. Your temp gauge should be just a hair below the midpoint after the car is warmed up. My Saturns all warm up within the first 5-10 miles of starting. You may also want to change you Coolant temp sensor its a 10 dollar part that will fail if its got the plastic tip. Try going to www.saturnfans.com for more info.

Saturns are great little cars if you keep an eye on the oil and change it evry 3k miles. All of mine have over 200k miles and are still going strong.

 

[Highbeam]

If both core hoses are hot (like you can't hold it in yuor hand fr more than a few seconds hot) then your core is fine and you can do the T-stat.

I was with you until this. If the heater hoses were hot then there would be no problem. All you can do is check to see if one is hot and the other is not which means a plugged core. If neither get hot then a bad stat. If both get hot then there should be plenty of heat.

 

[mayhem]

I thought I said that. If one is hot and the other isn't, you have aplugged core...if both are hot the core is fine and you can look elsewhere.

 

[Flammam]

I have never seen a Saturn with a plugged heater core. I have seen many failed thermostats.

 

[Danno77]

I thought I said that. If one is hot and the other isn't, you have aplugged core...if both are hot the core is fine and you can look elsewhere.

I think that HB is saying that: if it's hot into and out of the core, then you don't have a heater problem NOR do you have a t-stat problem (cause you wouldn't be getting hot into the core)

let me try this (someone call me on it if I get one wrong). This will be Danno's BASIC car heat Troubleshooting:

1. Hot before radiator + cold after radiator = bad t-stat (stuck closed)
2. Warm before radiator + warm after radiator = bad t-stat (stuck open)
3. Warm before core + warm after core = check for #2
4. Cold before core + cold after core = check for #1
5. Warm before core + cold after core = clogged core + check for #2
6. Hot before core + cold after core = clogged core
7. Hot before core + hot after core = check control knob + wires+ assembly + blend door
8. Cold everywhere = check water pump


is this too simplified? it's early in the day, feel free to correct me, i'll come back and edit it as needed. (need to finish this first cup of coffee)

 

[mayhem]

Got it, guess I wasn't really typing what I was thinking.

I think the only thing you mght have missed is a bad temperature blend door. If the coolant system is working just fine and you have a hot heater core, you still won't get hot air out f the vents if the flap doesn't divert fresh air over the core. Not a common issue on older cars with cable operated flaps and when those broke you knew it because the levers would move unusually easily, but virtually all newer cars have little servo-motors running the blend doors now.