1998 chevrolet silverado 305 engine with about 143 000kms on the engine. After a drive you can smell an odor of coolant coming from out under the hood. Done pressure test but could not find out where it was coming from. Oil doesn't appear to have coolant in it and the truck isrunning fine. I am puzzled. Would like to find problem and solve it. I hear that the intake manifold onthese engines are the culprit in most cases. Also if the intake manifold is the problem should I replace the cylinder head gasket while I am at it. Where would I find good quality gaskets on line. Any help would greatly be appreciated.

 

Woah, before you start tearing into the intake manifold take a very careful look around the engine bay, a minor coolant leak will evaporate off and leave a chalky residue that can easily be overlooked. If you have older hoses feel them for inconsistencies; Iv had a hose that looked fine literally make a crunching noise when I squeezed it. You could put in a container of Barrs stop leak but that's just delaying the inevitable. The best course of action available to you is to buy a flush kit and flush the snot out of your radiator; this should make your leaks more visible. Id also pickup in a new radiator cap, if you have the wrong cap for your vehicle or if its old, you could be over pressurizing your system. Good luck and happy hunting!

 

Think I found the problem. It does appear to b teh intake manifold gasket. It is leaking near the rear of the engine which is the reason for being so hard to find. Not a real big job to replace just a nuisance more than anything.

 

I'm having the same problem but i can see mine it looks like it's leaking around where the pump mounts to the eng. has anybody heard of that happening?

 

Could be that your water pump is on its way out... If your pump is noisy that could be another indicator that its wearing out.

 

it's not noisy and its not leaking out of the weap hole just around where the pump mounts to the eng.