Hey y'all. I'm looking for a little advice before I start on my head gaskets. I'd really like to find out if the leak I have is actually from a head gasket, or if it's from loose bolts on the upper/lower intake manifolds. Can anybody walk me through ruling this out before I start on the bigger project? On another thread somebody said these bolts could be checked by just removing the air cleaner. But I'm a little confused which ones other than the ones on top of the upper intake manifold.
It's running down in the (driver's) left rear of the engine (Bosch V8), but I can't tell if it's coming from the valley pan gasket or if it's from the head gasket.
I have done my own DIY pressure test and it loses about 3psi over 15 minutes.

I'm hoping against all odds that I can make it through the winter by re-torquing some bolts and then start on the project in the spring.
I'm losing about a half gallon of coolant a week and it drips right onto the cat (and O2 sensor) and burns off.

I am sitting on a new thermostat and new radiator and have plans to purchase a new water pump, head gasket kit, GREEN coolant (as per Disco Mike's instructions), plugs/wires, etc. Planning to do it all in one project but not exactly flush with cash at the moment.

Thanks for everything I've already learned from you guys!

 

That's a lot of coolant to be using in a week. Are you sure it isn't leaking at the throttle body heater? That's the plate under the throttle with 2 hoses going to it. If it leaks there, coolant will run off the back of the engine. There will be coolant on top of the valve cover also. If it isn't leaking there, then you can look for signs of it on the rear of the valley pan gasket. It is difficult to see back there because of how the intake is installed but you may be able to feel coolant back there. If there isn't any coolant at the rear of the manifold then it would be the head gasket.

 

It's definitely not the throttle body cooler. The previous owner had this fixed just before I bought it.
I should mention that I also did the dye test and have spend probably 2 hours looking all around the engine with mirrors, flashlights, and UV light. There is very minor seepage coming from the water pump. But a very distinct drip from the back that runs down on to the cat and also along the frame rail to the bell housing. I'm pretty sure it's coming from either the HG or the VP gasket. I'll be damned if I can get a mirror into a position to know for sure though.
I'm going to stick my hands back there a little more as you suggested and see if that helps.
I also think I figured out which bolts to check for looseness. Are they the 12 bolts around the spark plugs that go through the lower manifold?

 

The bolts near the spark plugs are the head bolts. I wouldn't mess with those. The intake bolts are not accessible without pulling the upper intake. That is actually not that difficult and only requires one gasket. You can pull that off to confirm where the leak is coming from.

 

rent or borrow a pressure tester, keep the reservoir full and bring it up to 16psi and keep it their until you find the leak'
if your loosing 3psi over 15 minute and a 1/2 gallon of coolant you have a sizable leak. Maybe you need someone else to keep the pressure up while your looking, i would look at the back of that head from the top with an inspection mirror.
also is that you crankshaft position switch that all that coolant is leaking on?

 

From my past experience, it usually comes from the failure of the rear rubber seal of the lower intake (valley pan) manifold gasket. This is if you're not getting overheating, coolant in oil or coolant in combustion chamber (white exhaust smoke)...just a loss of coolant from an otherwise normally operating engine.

These have a tendency to get hard and fall apart after 10+ years of use.

 

Good to know. I'm not getting any overheating. I watch my ultragauge obsessively. And there's no coolant in the oil. I'm guessing this is the problem so I'm going to pull the intake off and find out for sure. It will give me some practice at starting out the head gasket job.
And yeah Drowssap, it looks like that is my crankshaft sensor that's all gunked up. I think it is mostly oil. I better get it cleaned up regardless.

 

No conclusion