understanding exhaust smell

[Fordman999]

So guys I just finished replacing my catalytic converter and O2 sensors And I am still losing gas mileage and I have a feeling my check engine light is going to come back on. The mechanic reset it and it usually lights back up after a few hundred miles after resetting it with the battery. so my next suspicion is that I have coolant going through a head gasket but how can I tell if the exhaust smells like coolant?? I swear I think it smells like maple syrup but maybe I am imagining that now that I read a sweet smell indicates coolant leak. What is my exhaust fumes supposed to smell like? I do not have any white smoke out of the tailpipe so I don't think its a head gasket. Again I think the exhaust smells sweet but I think I think that because I read any sweet smell is coolant. again is an exhaust supposed to just smell like nasty fumes?

 

[Fordman999]

Also forgot to say

i also think I saw traces of coolant from the bottom of the intake manifold. i was wondering how I can confirm that the gaskets might be worn I'm just not sure.

 

[Number4]

A sweet smell is associated with coolant. You can pull your plugs and see if any of the Pistons have shiny spots on them. Coolant (water) will remove carbon from the piston on the compression strokes.

 

[Fordman999]

A sweet smell is associated with coolant. You can pull your plugs and see if any of the Pistons have shiny spots on them. Coolant (water) will remove carbon from the piston on the compression strokes.

thanks Number4 I'm going to try that. is there any easier way? so just look for the shiny piston head? is it hard to replace the head gaskets? I have all the tools to do the repairs I'm a hvac mechanic and my company provides about every mechanic tool you can think of a lot of current hvac mechanics were former car mechanics. now I wasn't a former car mechanic but a lot of those guys come over to my field since it is somewhat similar.

 

[Joe in NY]

if you have coolant leaking into your cylinders you will have exhaust gas leaking into your cooling system. When it's cold remove the cap, start it, and let it warm up and run. If it is bubbling in your coolant tank and you are getting gases coming out, you have a problem.

Cooling system run 15 psi. Before detonation in cylinder, 150 psi. Gas is going to go into your coolant more than coolant into the cylinder.

 

[TechGuru]

Smell will also be sweet if it's a FLEX running E85. Kinda smells in-between the exhaust from a Zamboni at the ice rink (AKA propane powered engine exhaust) and alcoholic beverages.

 

[Fordman999]

Smell will also be sweet if it's a FLEX running E85. Kinda smells in-between the exhaust from a Zamboni at the ice rink (AKA propane powered engine exhaust) and alcoholic beverages.

Thanks for that info TechGuru I do have a Flex fuel and I do add E85 at gas stations since I have no choice! I did notice that I have some leaking under my vehicle that is running from the transmission and thought it was transmission fluid or that the bolts for the pan was not tightned enough now I suspect that it is the coolant running from my lower intake manifold and dripping onto the transmission and mixing with the crap on the transmission and around ( the black caked on stuff) and making it look like transmission fluid but Im suspecting it's actually coolant.

 

[Number4]

Inspect your thermostat housing for leaks.

 

[Fordman999]

Well everyone I think I found my problem. I placed a rag on the exhaust to cover it and heard some hissing noise from the exhaust pipe. Upon closer inspection I noticed that the original pipe clamp that connects to the muffler is rotted and there is a small hole at that location. I noticed because when I covered the exhaust water began leaking out of that hole. Now to be clear I do know there is a weephole on the muffler to release water accumulation. A good amount of condensation water was coming out from the clamp connection and it looks very rotted. Amazing what a new 300 lumens flashlight and good eyework can find!! Already ordered the exhaust pipe for $30 hooray!!!

 

[Fordman999]

The coolant leak is a whole different story...my Explorer is 2003 with 186,000 miles I noticed some traces of leaking on the bottom of the manifold. Man I tell ya a good flashlight will make a world of a difference