I have an 04 4.3L vortec with 65k on it. I bought 6 months ago- obviously did a lot of sitting before that. Its leaking coolant - found it on backside of thermostat for sure... do you guys think coolant from thermostat caused these 2 puddles in the divets?- 2nd pic is the puddle under throttle cables/body. The seal to the right of the thermostat is leaking too- intake manifold?

Had a 2000 Blazer that I did minor work on & really don't want to pay a mechanic to diagnose/fix this- thermostat no worries, not sure on the other......

 

In both images, the arrow pointing up is the lower intake manifold gaskets leaking coolant. The arrow pointing down, appears to be oil, which is taken care of when the intake gaskets are replaced as well. Felpro MS98002T gasket set will not leak if clean up is done properly and tightening sequence and torque specs are followed. Not a difficult job but it is time consuming. You'll need an accurate inch pound torque wrench, but no other "special" tools are needed. If you haven't done intakes before, allow most of a day to do the job.

 

Thanks Captain!.... So the intake gaskets are above the puddles of coolant? There is definently an accumulation of coolant on that ridge & then to those puddles- pics are after I cleaned a lil. Also, I really thought the moisture seeping @ the down arrow was coolant- ill check again after my commute today, I guess it could be running down... steadily larger amount under the truck after every trip.

 

In the 2nd image, just to the left of the arrow, there's a bolt, there's another one just forward of that one, next to the heater hose. There are four bolts on each side of the engine. The bolts go through the intake manifold and into the cylinder head. There's a gasket between the intake and the head on each side of the engine.

 

Captain- I see the bolt heads you point out & have reviewed the D-tips walkthrough. Doesn't look too bad, just a lil scary(removing distributor for one) - I've never done a job with as much ignition/engine work. Bolt on/off no problem- brakework, radiator, waterpump, balljoints, tierods, front wheelbearings, distributer cap(learned the hardway to use ACDelco)...

I attached a pic from today. It looks to me like the upper black plastic seal is seeping as well as the lower aluminum manifold. Rockauto has Felpro upper & lower package... I guess i should prolly just do both & thermostat?

 

D Tips is pretty good, but it's not 100% and it leaves out a few very important steps. Not a bad idea to replace the stat while you're in there. Don't let the distributor intimidate you. When you're ready to do the job, let me know. I can explain how not to mess it up A different method that is very simple and darn near "fool proof".

 

Thanks again Captain. I ordered the Felpro upper & lower Gasket package as well as the thermostat. I'll prolly attempt to tackle it in 2 weekends. I'll keep you posted.