baffled

[willtillery]

hoping someone else might have had this issue and figured it out...definitely not hoping anyone else has had this issue though.

d90 1997
upon start up every day /only start up after truck has run for 60 secs their is about a 5sec smell of coolant.

you dont smell it anymore until the next day upon start up again.

my initial thoughts were intake gasket/when cold was letting coolant pass when hot was sealing up.

i have replaced the intake gasket/valve cover etc
no leaks to be found around heads/checked for gases in the coolant/replaced all hoses/checked all plugs/reservoir cap is fine/radiator looks good.- no whitish trails anywhere to be found.

their is no major coolant loss- after checking the level for a week now the level appears to remain the same. it is almost like someone is taking an eyedropper and dropping a small hint of coolant on the truck somewhere.

the only thing i have not checked is the heater core.

[Mike Hippert]

Do you get a white puff of exhaust when you start up?

[Abrooks]

I've had the coolant lines at the intake manifold develop pinholes twice now, produced the same sort of smell.

[Davis]

Check the top of your valley gasket, especially in the rear near the bulk head--even take some paper towel and shove it in the gap between the air intake manifold and the valley gasket and see if there is any coolant there (it will only take a little to be able to smell it). Sometimes it is the lines cooling going to the intake manifold, sometimes at the thermostat. Worth a look.