: Coolant smell from heater; how screwed am I?



The_Raven
02-17-04, 12:45 AM
Howyadoin,

Started up the '96 SLS this evening, and smelled an odd odor from the heater, smelled a lot like the air released from a tire when you are adjusting pressure. I have a slow leak on my front left wheel (damn chrome rims, I think, getting it checked), but this was way too strong to be that. So then I smelled something like paper burning, but that went away. So I'm left with this strong smell that I'm guessing is Dexcool.

No leakage outside the car
No steam from the engine compartment
No condensation on the windshield when front defrost is turned on, although fans don't run very long.
No dampness that I could detect on the carpets
Engine temperature consistent with weather conditions

The heater fans start up, but then shut down after 5 seconds or so even in manual mode.

So the question becomes, what next?

Assuming the heater core is leaking, can I use Barsleak Gold to fix the problem? If so, is the procedure the same as for a non-Dexcool motor?

The fan situation concerns me... Is there a air output temperature sensor that might be keeping the fans from continuing to run after that initial 5 seconds or so?

If the heater core needs to be replaced, how involved is it? Are we talking dismantling the dashboard?

ARRRGGGHHH... Help please?

-Mark P.
Salem, MA

BeelzeBob
02-17-04, 11:00 AM
Howyadoin,

Started up the '96 SLS this evening, and smelled an odd odor from the heater, smelled a lot like the air released from a tire when you are adjusting pressure. I have a slow leak on my front left wheel (damn chrome rims, I think, getting it checked), but this was way too strong to be that. So then I smelled something like paper burning, but that went away. So I'm left with this strong smell that I'm guessing is Dexcool.

No leakage outside the car
No steam from the engine compartment
No condensation on the windshield when front defrost is turned on, although fans don't run very long.
No dampness that I could detect on the carpets
Engine temperature consistent with weather conditions

The heater fans start up, but then shut down after 5 seconds or so even in manual mode.

So the question becomes, what next?

Assuming the heater core is leaking, can I use Barsleak Gold to fix the problem? If so, is the procedure the same as for a non-Dexcool motor?

The fan situation concerns me... Is there a air output temperature sensor that might be keeping the fans from continuing to run after that initial 5 seconds or so?

If the heater core needs to be replaced, how involved is it? Are we talking dismantling the dashboard?

ARRRGGGHHH... Help please?

-Mark P.
Salem, MA

From what you say it sounds more like the HVAC blower motor speed control has fried.....

Lack of the blower fan would not be related to a heater core leaking......

If you have heater core leaking you would know it with the unmistakeable smell of coolant (DexCool and the green stuff are both 99% ethylene-glycol...so they smell the same) steam from the vents, wet , yucky carpets, etc.... I don't think you have a sudden heater core issue.

You so have the BarsLeaks/GM coolant supplement in the system already, right??? After all the conversations about that it should be in there already protecting you from just such an occurance....LOL

I would check the voltage to the blower motor feed for power. Probably the speed control has died and that means the blower motor needs replacement on yours as I think a 96 has the integral blower speed control in the motor.

There was lots of info on this on the old caddyinfo forum that you might search there for an update/refresher.

The_Raven
02-17-04, 11:30 AM
Hey Bbob,

As far as the coolant supplement, I just bought the car Thursday, and haven't contacted the dealership where the guy had the car serviced to see if I can get info out of them regarding what service has or hasn't been done. It's at 122K with Dexcool, so I was going to do the coolant this weekend regardless just to know that it had been done and done with the pellets. I've learned well the importance of cooling system maintenance on the Northstar.

I'm definitely getting a powerful whiff of coolant in the interior, but the carpets seem OK, unless the coolant is going underneath...

Just as an aside, I swear there are cycles of problem reports on these boards, and I seem to be in synch with a lot of them. The EGR period back in 2001 when everyone was having EGR cleaning parties, the shift solenoid festival of 2003, and now it seems like every other post is about cooling system issues. Maybe it's just perception?

-Mark P.
Salem, MA

BeelzeBob
02-17-04, 12:15 PM
Hey Bbob,

As far as the coolant supplement, I just bought the car Thursday, and haven't contacted the dealership where the guy had the car serviced to see if I can get info out of them regarding what service has or hasn't been done. It's at 122K with Dexcool, so I was going to do the coolant this weekend regardless just to know that it had been done and done with the pellets. I've learned well the importance of cooling system maintenance on the Northstar.

I'm definitely getting a powerful whiff of coolant in the interior, but the carpets seem OK, unless the coolant is going underneath...

Just as an aside, I swear there are cycles of problem reports on these boards, and I seem to be in synch with a lot of them. The EGR period back in 2001 when everyone was having EGR cleaning parties, the shift solenoid festival of 2003, and now it seems like every other post is about cooling system issues. Maybe it's just perception?

-Mark P.
Salem, MA


I think the internet has that effect.... People search out the forums to find out about their problems...not to brag about how good their car is running. An there is a certain amount of "car hypochondriacs" I think....LOL They read about a problem and assume they have the same problem or start imagining it on their ride.... It is really misleading to read about a problem on one car and immediately assume that all of them will do that...which is what often happens I think.


I notice the cycle of problems definitely trends toward "no heat" in the fall/winter to "no AC" in the spring summer. Obvious I guess. I commmented much the same as you did back about a year ago on the old caddyinfo forum about the surge of similar problems. The worst was everyone cleaning their EGR tubes on the 4.9's....and people trying to clean them on Northstars...LOL


If this is a "new" car to you I would do the cooling sytem and when it is drained, pressure check it to see if you can "hear" any hissing in the HVAC case from a heater core. It will be much more noticable if you pressure check it when the system is empty or full of air as the air will leak thru any orifice much more obviuosly than coolant if it were pressure checked full of coolant.

I wouldn't worry about the service records. It needs draining and refilling anyway to just add the coolant supplement pellets as they need replenishing with the new coolant as well.

The_Raven
02-17-04, 11:25 PM
Howyadoin,

Hey Bbob, is it true that the pencil shavings in your pocket protector can cure cancer? :)

You nailed it! It was the blower motor that was toast, replaced it and all is well. Not an easy job, but I've got a king-hell mechanic with the proverbial "bitchin' set of tools" who keeps the greasy parts greasy, donchaknow... He was spot-on with the blower motor diagnosis as well.

BTW, that was one nasty-ass stench from the blower motor. It's gonna take a few of those pine-tree air freshener thingies to cover that up. But like I said in my car journal on caddyinfo, I'd hang those bastards like dingle-balls rather than have to rip the interior apart to replace the heater core!

Thanks as always!

BeelzeBob
02-18-04, 11:53 AM
Howyadoin,

Hey Bbob, is it true that the pencil shavings in your pocket protector can cure cancer? :)

You nailed it! It was the blower motor that was toast, replaced it and all is well. Not an easy job, but I've got a king-hell mechanic with the proverbial "bitchin' set of tools" who keeps the greasy parts greasy, donchaknow... He was spot-on with the blower motor diagnosis as well.

BTW, that was one nasty-ass stench from the blower motor. It's gonna take a few of those pine-tree air freshener thingies to cover that up. But like I said in my car journal on caddyinfo, I'd hang those bastards like dingle-balls rather than have to rip the interior apart to replace the heater core!

Thanks as always!

Where you live there MUST be someone that can exorcise that smell.....LOL

Glad that was the problem.