Engine help!!!
 

Good Day Y’all,

Have a couple of issue and I know this forum can help, this place has yet to let me down.’

ISSUE #1
My vehicle has a vibration, an engine vibration between idle to about 1500 rpms. I have done a search and thought it could have been engine or tranny mounts but after testing it, it doesn’t seem the case.

Was wondering does anyone have a clue as to what it might be and if so what can I do to verifiy the situation.

ISSUE #2
I notice that my antifreeze has been dropping. I did a search on here and it could have been anything from intake or head gaskets to thermostat or heater core. I was sure it was not the heater core since I have no antifreeze smell, no fogging of the windows, not visible leak outside or in the vehicle, etc, etc. I knew it wasn’t a gasket because my oil was not unusually high.

I finally took off the passenger inner fender (WTF Chevrolet was thinking there) and notice a cable grommet (I assume for the A/C) was dripping antifreeze so I now know it is the heater core. The issue is to take off the dash are there any pictures anywhere to show me?

I have a 2000 LS 4.3 with A/C.

All I hear is crickets!!!!
 

Can anyone help?

Please have a little patience, it's been only 5 hours since your first post. Nobody gets paid to monitor this place. :icon_wink: I'm sure responses will be forthcoming.

An intake manifold gasket can leak to the outside where the heat of the engine will dry the coolant before it gets a chance to drip on the ground. It can also leak into an intake port where it would be pulled into the cylinder and passed out the exhaust.

A compression check would tell you if you have a head gasket problem. If its bad enough, just looking for a steam cleaned plug would give you enough info to say its a bad head gasket.

As far as the vibration between idle and 1500RPM, does it do this in all gears at the same RPM? How have you concluded that it is an RPM based vibration?

Vibration & pressure test
 

As far as RPM based the vibration reduces considerably above 1500 rpms.

When I start it it vibrates, place it in reverse it vibrates, place it in drive it vibrates until I hit about 1500 rpms and then the vibrations seems to cease.

That is why I assume it is RPM based.....

Pressure test?
Is this the same as a heater system pressure test?
Would I lose as much as a gallon of coolant a day this way?

I am confused the motor has 101K and never had any real issues until now

Any and all help is greatly appreciated.

I do apologize for being quick for a response but it is my work/personal vehicle and would hate to tear it up more than I have too.