Hello, I am new to this forum. I have a 1998 GMC Sierra SL 6cyl 4.3 with 108K miles. For the last few weeks, when I drive it, I notice the smell of coolant/antifreeze. The truck is not running hot, and is not running or idling rough. However it is slowly losing coolant, as I've had to put coolant in a couple of times even though there are no signs of coolant leaks on the ground. I'm far from being a mechanical expert, but my fear is that this is a dreaded head gasket problem. Needless to say, being such an old truck, I don't want to put a lot of money into repair. So, any advice/help from fellow GMC/Chevy owners would be GREATLY appreciated.

Thanks!

 

any oil/coolant mix in raditor? it be milky looking. if so head gasket. check ur hoses an connections, maybe weeping water pump...

 

Also check your oil for coolant contamination. The oil will smell like coolant, and be a milky color.

If you really want to know if it's a head gasket, take it to a shop and ask them to do a leak down test on it, and a cooling system pressure check.

 

Usually if you are smelling it it is leaking around the engine somewhere - unless you are standing behind it while it' running and smelling it through the exhaust. That should give you some steam out of the exhaust as well. If you have inspected it and can't find any coolant it is probably leaking out of the back of the intake and you are smelling it burning off the hot engine. Obviously inspect your oil and make sure there isn't any there. Does it have the coolant smell under the hood?

 

I had a leak like this from the tanks on the radiator. It was so hot that it mostly dried up before hitting the ground. If you fear it is a blown head gasket, pull the O2 sensors and see what color they are.

 

heater core?

 

I was having the same issue.there is a heater hose (quick connect) at the rear of the manifold leaks very small amounts.it might break off if you try to replace.if you have know how you can check into changeing it to a regular fitting.