[BONE WSO]

Newby here. Original owner - 99 SLT 2WD 5.2 V-8

For a couple of months I have noticed a bit of a burnt coolant smell when I get out the the D. It has recently gotten more intense. I bled the brakes the other day and finally think I found where a possible leak was coming from - there is a short, quarter sized something protruding from the firewall on the passenger side(weep hole?). This is the only evidence of any leak, but the fluid did not smell like antifreeze. All hose conections are secure; hoses in good shap with no evidence of fluid run-along underneath; no leak around the water pump. The radiator overflow tank does noticably lose fluid, which leads me to believe the problem is getting worse.

Any help would be appreciated.

Thanks

 

[Unnamed]

Maybe you have a bad head gasket and the leak is dripping on to your exhaust manifolds and cooking off?

 

[canyonD]

the drain you located was probably the AC system drain for your evaporator in your HVAC unit. This is unrelated to your problem.

I am going with Don on this one. Unfortunately, you probably have a head gasket leak.

 

[BONE WSO]

Head Gasket - sounds painful. I don't suppose the JV DIYer with continuous 8 yr old "help" could accomplish something like this over a weekend? I see that the gasket is no more than $30. What would it take for a real mechanic to accomplish in terms of both time and money?

:gr_patrio

 

[Chump]

Possible leaky freeze plug on the engine block?

 

[canyonD]

another possibility. If you start having freeze plug problems, you may have a grounding issue.

 

[WarrensD]

No moisture on the passenger side carpeting? (also BAD news)

 

[Rick99]

My 99 had similar symptoms-- it turned out that the thermostat housing gasket was leaking. Rule this out before you go replacing the head gasket!

Follow the upper radiator hose to where it goes into the engine, use a flashlight to look down where it attaches and if you see greenish crystals around there you found the problem. The coolant can also drip from there onto the passenger side exhaust manifold, so look for evidence of that.

Replacing the head gaskets is a lot of work, rule out the other possibilities first. Since you smell the stuff burning, you should be able to find evidence of the leak on the exhaust manifolds and follow the trail from there. Remember that liquids will flow down and toward the back (because of air flow.)

 

[BONE WSO]

Thanks fall or the help. I have a couple of uninteruppted hours tomorrow. And to answer the posed suggestion, there is no evidence of fluid on the passenger side carpet suggesting a heater core problem. I will check all options and let you know. After a little study, I've determined that I don't want any part of a head gasket repair.

You guys rock!

:gr_patrio

 

[cbrenn71]

how about the possibility of a bad radiator cap?

 

[Unnamed]

how about the possibility of a bad radiator cap?

It's so simple it's beautiful. Let's hope this was his problem!

 

[cbrenn71]

i just say that because i have a 98 chevy 1500 that has had a bad burnt coolant smell for sometime. a few weeks back, i went to check the coolant, and the cap came apart into three pieces. that was the problem.

 

[canyonD]

Maybe this is his lucky day. Hoping it is only an inexpensive radiator cap!!

 

[BONE WSO]

Thanks for all your suggestions.

Upon closer inspection, the thermostat gasket was leaking by the front bolt on the housing mount - more specifically, hidden under the "Front" tab attached to the mount to keep people like me from installing it backwards. Long story short, the coolant was slowly sneaking out and cooking on a concealed part of the block without leaving any obvious evidence of a leak upon initial inspection. A "quick" thermostat and gasket change fixed the problem.

Lesson learned - (after far to much time spent trying to wriggle my hand and a screwdriver around with enough force to scrape away cooked old gasket remnants from the housing) - Mr. Dremmel is your friend!

Thanks all.

:gr_patrio

 

[cbrenn71]

glad to hear it's all good.

 

[Unnamed]

Whats around there that's hot enough to cook off the fluid? I didn't think the block got hot enough for that.

 

[canyonD]

sweet

 

[cbrenn71]

the fluid is probably all he is smelling, warm 160 degree fluid smells pretty nasty and pungent no matter where it is coming from.

 

[Rick99]

As I said above, that's exactly the same problem I had with my D, and yes, it is hot enough to evaporate the liquid out of the coolant leaving only some green crystals as evidence.

I've been told this is a common problem with 5.2 and 5.9's. When I had the problem, I didn't notice any smell, I just had to keep topping off the coolant and wanted to figure out why.