Well, got it changed out. Absolute pain in the *** with no room to work but got it done. The noise is still there though.

After standing over the engine, it almost sounds like something internal is going on. A lifter maybe? Clogged injector? I have no idea. But the the noise goes away once the engine is warmed up.

 

You checked all manifold bolts? When was the last time you changed your oil? Full synthetic? What brand fuel do you use? More information NEEDED!

 

All the manifold bolts that I can see look fine on top, minus the last one on the driver's side rear. I can't get a view to see below at the bottom row though.

Oil changed regularly, Mobil synthetic. Oil pressure is good.

No check engine light or anything else unusual.

 

check for leaks.

 

The rear most driver side exhaust manifold bolt also just happens to be the most common one to be broken.... Dorman makes a clamp sort of thing to fix it that bolts into a threaded spot on the back side of the block with a bolt that presses the manifold tight back against the head. Works very well and is generally easier than trying to extract that broken bolt in place. Easiest way to get to it is to remove the wheel and wheel house liner.

 

i am using one of those clamps in that location it works well. now finding that hole on the back of the head blind near the firewall took a while. would have helped if it had hair.

 

LOL - yeah when I put my long tube headers on that was the only broken bolt out of 4 that I was unable to extract. Gave up and stuck that bracket on - works great and yeah, it is totally blind trying to get that bolt started on the back.

 

I only have one bolt missing on the driver's side rear, no other bolts on the exhaust manifold bolts are broken off.

After installing the repair clamp, it does help, but the loud noise is still there when I start a cold engine.

The noise is loud and sounds like it's coming from the engine area.

 

Did you check for leaks? Cold engine, blow air into the tailpipe, listen for hissing at engine.

 

How about this possibility:

There is a clutch on the radiator fan.
When the vehicle is cold, or after pressure washing engine, you may get a "schluck shluck" sound.
Similar to what drum brakes on a car can do.

Once the vehicle warms up (or clutch dries up), the noise goes away.

Does it sound like it could be coming from that area?