Coolant burning/boiling type smell, everyone once in a while.

06TrailblazerLSS

Original poster
Member
Apr 28, 2014
93
My buddy has an 05 Trailblazer LS, it smells like burning or boiling coolant. Or like coolant is leaking onto something hot.

I got under it and only see/smell water dripping after its been running and parked. Was told to "taste" the water to make sure its not coolant, if coolant it should taste sweet. Didnt really taste sweet lol.

Anyways, also was told it could be heater core or hose leak. Anything similar happen to anyone here? Truck has about 85k miles. Just started smelling yesterday, no high temps on dash. Smells and then it doesnt, etc.

Any help appreciated.
 

The_Roadie

Lifetime VIP Donor
Member
Nov 19, 2011
9,957
Portland, OR
If it's from behind the passenger wheel well spilling on the ground, that's often AC condensate - pure water and not hot. You need to do a close inspection to locate the smell.

And my usual questions: How many miles? Any major maintenance history? Is he current on all fluid changes and spark plugs?
 

triz

Member
Apr 22, 2013
746
You might want to check the drivers side area of the engine near the clutch fan. If the coolant leaks from there its usually small and will burn out quickly. If its in that area its your water pump (or his).
 

06TrailblazerLSS

Original poster
Member
Apr 28, 2014
93
BlazingTrails said:
About what area is the liquid coming from?
Thats the thing not sure, but what I think is the normal water drip is dripping from where the hoses meet the firewall, where it usually drips. Same spot where water drips from mine too. Thing is not sure if water or coolant

Right near the passenger wheel area, or under passenger dashboard area.
 

06TrailblazerLSS

Original poster
Member
Apr 28, 2014
93
The_Roadie said:
If it's from behind the passenger wheel well spilling on the ground, that's often AC condensate - pure water and not hot. You need to do a close inspection to locate the smell.

And my usual questions: How many miles? Any major maintenance history? Is he current on all fluid changes and spark plugs?

85k miles or around there I think. He keeps up with it, no bad maintenance history besides belt tensioner and basic stuff. He is due for an oil change,but not far behind the sticker date. I took off his coolant cap and stuck my nose in there, smells very similar to what he described and what I partially smelled- like boiling syrup or something.
 

06TrailblazerLSS

Original poster
Member
Apr 28, 2014
93
triz said:
You might want to check the drivers side area of the engine near the clutch fan. If the coolant leaks from there its usually small and will burn out quickly. If its in that area its your water pump (or his).
Next time I see it will check there, thanks!!

And thanks everyone for input thus far. No one likes mechanic/dealer bills!
 

06TrailblazerLSS

Original poster
Member
Apr 28, 2014
93
The_Roadie said:
If it's from behind the passenger wheel well spilling on the ground, that's often AC condensate - pure water and not hot. You need to do a close inspection to locate the smell.

And my usual questions: How many miles? Any major maintenance history? Is he current on all fluid changes and spark plugs?
His coolant also seemed low. Is it normal to not see coolant when opening the dexcool coolant lid after a few hour drive in traffic? I see the cold level line but didnt see the hot level.
 

Hatchet

Member
Nov 21, 2011
2,405
06TrailblazerLSS said:
Thats the thing not sure, but what I think is the normal water drip is dripping from where the hoses meet the firewall, where it usually drips. Same spot where water drips from mine too. Thing is not sure if water or coolant

Right near the passenger wheel area, or under passenger dashboard area.
Sounds like the drain line for the AC system. Was he running the AC at this time?

A loose or no pressure sealing radiator cap can give that smell off. The only way to go about this is, try and find a leak. Drive it around till the engine is nice and hot and the thermostat opens. (leave the AC off to eliminate the drain tube water) and park it and look under the hood and under the engine to see if you can find a drip that looks or smells like coolant. Atleast to narrow it down to what area of the engine.
 

NJTB

Member
Aug 27, 2012
612
Flemington, NJ
You can also try the flouresent dye in the coolant. It will show the leak with a blacklight.
FWIW, I changed the water pump on mine, and that smell hung around for a couple of weeks. I was sure I had a leak and looked everywhere, but no, it was just the coolant burning off.
 

06TrailblazerLSS

Original poster
Member
Apr 28, 2014
93
Hatchet said:
Sounds like the drain line for the AC system. Was he running the AC at this time?

A loose or no pressure sealing radiator cap can give that smell off. The only way to go about this is, try and find a leak. Drive it around till the engine is nice and hot and the thermostat opens. (leave the AC off to eliminate the drain tube water) and park it and look under the hood and under the engine to see if you can find a drip that looks or smells like coolant. Atleast to narrow it down to what area of the engine.
I asked, he is not sure if it was running when the smell came around. It was running at one point he says.
 

Sparky

Member
Dec 4, 2011
12,927
Mine was doing something like that except it was obviously orange colored in my case. In my case a heater hose fitting on the back of the engine somewhere had corroded and was leaking. Don't know exactly where as it was in December 2012 and I wasn't about to crawl under there to figure it out. A local shop fixed it for me.
 

loondog33

Member
Jun 25, 2014
84
My previous car, a 1999 VW jetta had a bad heater core, which made it stink of coolant bad. The defrost also would not work worth a crap because of the heater core.

At least I believe it was the heater core because I found a couple posts, years ago, in which people had similar issues. Had no leak and lost no coolant. Just smelled bad like coolant and defrost wouldn't work. So if you don't find a leak maybe check on the heater if possible.

But if replacing the heater core is as complicated as my old jetta, then good luck to you sir. I found a video on how to replace the heater core in my 99 jetta, and quickly decided a broke core was something I could live with! :no: At least an eight hour job just ripping everything off the dash to get to the front frame roll bar so you can loosen enough to get the heater core out, and it appeared that guy had done it many times before.
 

Wooluf1952

Member
Nov 20, 2011
2,663
Milwaukee, Wisconsin
06TrailblazerLSS said:
His coolant also seemed low. Is it normal to not see coolant when opening the dexcool coolant lid after a few hour drive in traffic? I see the cold level line but didnt see the hot level.
If there is coolant in the reservoir and the fluid in the radiator is low, the rad cap is probably bad. If the reservoir is empty, there is a leak somewhere.
 

06TrailblazerLSS

Original poster
Member
Apr 28, 2014
93
Radiator was full, coolant tank just looked low/empty. Buddy ads his girlfriend switched cars today so I was keeping an eye on it at work, no leaks on the ground and no leaks elsewhere that I could see. I also did some googling and saw a bunch of similar coolant smells because of the heater core. Any of you guys or anyone on here never has smelt this maple syrup burning coolanty type smell? Lol

By the way thank you very much to everyone posting
 

loondog33

Member
Jun 25, 2014
84
06TrailblazerLSS said:
Radiator was full, coolant tank just looked low/empty. Buddy ads his girlfriend switched cars today so I was keeping an eye on it at work, no leaks on the ground and no leaks elsewhere that I could see. I also did some googling and saw a bunch of similar coolant smells because of the heater core. Any of you guys or anyone on here never has smelt this maple syrup burning coolanty type smell? Lol

By the way thank you very much to everyone posting
If it helps, when my heater core went out on jetta, it did not smell burnt. Just smelt like coolant.
 

Texan

Member
Jan 14, 2014
622
If the coolant tank just looked low/empty, you need to add coolant to the cold line, and
check it after a heat/cool down cycle.
 

06TrailblazerLSS

Original poster
Member
Apr 28, 2014
93
How do we go about doing a basic coolant flush? I'm guessing it may help. Buddy says he hasn't changed coolant since he's owned it-4 years or so. Does coolant go bad? If so how long?
 

Mounce

Member
Mar 29, 2014
13,667
Tuscaloosa, AL
By cold line, I think he meant the cold mark on the coolant tank.

To drain the coolant, you have to pull the lower radiator hose because our radiators don't have a petcock (drain). I'm not sure how to go about "flushing" the system though, never had to do it.
 

loondog33

Member
Jun 25, 2014
84
From what I've read here on the site, to flush just pull lower hose let drain. Then fill radiator with distilled water, run engine for 15 min or so with the heater on full blast and let car reach operating temp then shut off. Drain and fill again with distilled water and repeat process as many times needed till you get all the coolant out. I've read it will take about 5-6 gallons of distilled water. After your last drain just fill back up with coolant at the proper 50/50 ratio, there will will plain water left in the heater core and block so you'll have to mix accordingly.

Just search coolant flush and you find more in depth details from more experienced individuals. Cheers.
 

Mark20

Member
Dec 6, 2011
1,630
NJTB said:
You can also try the flouresent dye in the coolant. It will show the leak with a blacklight.
FWIW, I changed the water pump on mine, and that smell hung around for a couple of weeks. I was sure I had a leak and looked everywhere, but no, it was just the coolant burning off.
Same thing when I did my thermostat and coolant temperature sensor. I even rinsed off the engine area with the garden hose. I guess the coolant was dried on.
 

BlazingTrails

Member
Apr 27, 2014
19,409
06TrailblazerLSS said:
Buddy brought his blazer to a shop, they could not find any leaks or issues.

Hmm...
Given the information provided my 'over the internet prognosis' is that the impeller came off of the water pump inside the engine. I would be willing to bet if you pull the water pump the impeller will be sitting right there in the block.

All the symptoms you provided would suggest it. And it is fairly common.

Good Luck :2thumbsup:
 
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06TrailblazerLSS

Original poster
Member
Apr 28, 2014
93
Does the water pump come into direct contact with coolant? Hot coolant/vapors seem to be coming loose off something every now and then, we were bouncing around on a bumpy road when I smelled it.

@blazingtrails- water pump easy to get to for a complete rookie like myself with very limited tools? They've got nearly $700 into just ridding a smell- heat and everything was fine all along.

@blazing trails- think the heater core coulda been fine all along?

Did have a wet passenger carpet, and nasty stench.
 

triz

Member
Apr 22, 2013
746
Sounds like you have it spot on. Given the quality of parts from China it would not surprise me one bit if the part you just replaced is bad right out the box. That being said inspect the common components, radiator (take a look around the top and look for anything wet around the gaskets), signs of the pulleys slinging coolant around. Check the engine block around the water pump. Check for leaks around hoses and the thermostat.
 
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C-ya

Member
Aug 24, 2012
1,098
My heater core is leaking, I think. Coolant smell when the heat is on, not bad, but enough to know it is there. I'm not ready to spend the money to have a shop do it since it is (supposedly) not covered by my aftermarket warranty. I found a thread from somewhere linked on these boards that showed a step-by-step R&R of the heater core. Yeah, that'll be a fun day, and definitely not in the winter!
 
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06TrailblazerLSS

Original poster
Member
Apr 28, 2014
93
Under both the coolant cap and radiator cap looked a bit wet, near the lid/cap area i should say- not directly under cap. Not a puddle or anything but definitely was visibly wet. Both caps are on tight as they can go. I don't know where else to look, but the belts look dry and no moisture near passenger carpet.
 

Mounce

Member
Mar 29, 2014
13,667
Tuscaloosa, AL
Is it overheating any? Weird that fluid would leak from the reservoir cap considering the fluid doesn't normally (or ever? Idk) come in contact with it.
 
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Mooseman

Moderator
Dec 4, 2011
25,262
Ottawa, ON
If the hose is leaking despite the clamp being tight, you might need to double clamp it. Add another clamp right beside the other one with the worm gear on the opposite side.
 

Mounce

Member
Mar 29, 2014
13,667
Tuscaloosa, AL
Funny...I just looked at mine and I'm also leaking coolant. Appears to be coming from the cap.
 

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christo829

Member
Dec 7, 2011
497
Fairfax, Virginia
I had the same intermittent smell and slow loss of coolant from the reservoir, along with wet spots by the cap. Turned out that the o-ring inside the cap was no longer sealing consistently. Replaced the cap, and the smell, loss and wet spots went away. When I compared the old and new caps, the o-ring on the old one was very slightly flattened.

Good Luck!

Chris
 

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