Clumps of brown substance under radiator cap. I was thinking it is oil mixing with water which is what I filled up the cooling system with as im having a continuing issue with lower intake gasket not sealing. My vacuum readings are fluctuating from 11 to 14 inches. Engine shaking and stalling at idle. I just replaced rings and bearings. Am running a tfs stage one cam with pro comp heads. Compression test. shows150 psi in all cylinders. The only code is a 136 which is left side o2 sensor showing a lean condition.
Have you done a coolant system pressure leak down test? It might be Bars Leak or someone put power steering fluid in the overflow tank (yes, a greasy monkey did that to my Grand Marquis). The adapter and pump with gauge are available to borrow at Advance Auto to make sure it is not a head gasket or intake gasket.
Yes I just got done doing that coolant system pressure test it held 15 for at least 5 minutes. As far as somebody else putting something in the in the engine it couldn't happen that engine was completely overhauled by myself over the last couple of months and I know there's been nothing put in that car. The only other thing I can think of is possible residual from the hot tank at the Machine Shop or maybe it's just rust because I've only been putting water in for coolant as I'm having a heck of a time with lower intake manifold gaskets and I didn't want the chance of glycol getting on the bearings. Correct me if I'm wrong but if the coolant ports on the lower intake are leaking wouldnt it result in coolant in the oil and not oil getting into the coolant system? I guess I'm going to have to put antifreeze in there to see if I get the white smoke out of the exhaust because with water it's hard to really tell if it's getting into the combustion Chambers so at least I could rule out that water is getting into the combustion Chambers because the engine is running rough as stated I only have one code for an oxygen sensor but I don't think that would cause it to run rough upon initial starting before it goes into closed loop
I like most of your deductive powers up to now!
If you are wanting to avoid glycol oil jelly, you at least need the anti rust/corrosion additives in something like a Water Wetter. Unless it is distilled water, you might be right about rust. How about UV dye in the coolant? That would sure help make sure it is not ending up in the oil. If they have a different color for the oil, it might help make see what is leaking, or just make a confusing mix if done at the same time.
Did you use the paper only or steel core Fel Pro intake gaskets?
Scroll down in this thread until you see jrichker’s FINDING VACUUM LEAKS.
I checked for vacuum leaks. I sprayed around the blower inlet, every connection to the throttlybody and around it. Then I sprayed the lower intake where it sits against the heads and front and rear of the block. I sprayed the upper to lower intakes and spacer. I sprayed along the vacuum three...
I had an engine that was milled and heads decked. The only way I got it to seal was with 1/16 thick intake gaskets from advance auto parts. I think it was Felpro but not sure. That thing sealed right up with the normal sealant around the coolant ports.
The intake may be causing your lean issue....but if the coolant passage was leaking you'd get water dripping from front corner, in the intake port, or into the oil through the valley. Water and oil would be a chocolate milk color. If stop leak was in there it could be circulating through the radiator or heater core....it wouldn't have to be in the block to get mixed around. Back I'm the day we used egg whites and pepper....it worked but was a very bad idea. All that stuff is garbage.
Actually, Bars Leak is industrial strength rat poop. ... Take a look next time you are at the parts store and shake a bottle.
The radiator shop that boiled out my 1965 radiator recommended I run two (containers? Rolls?) doses of Silverseal in my coolant system in case it ever springs a pinhole leak. That powder does not plug the heater core unless it’s corroded up and about clogged anyway.
The OP did not say it was Bars Leak. I was brainstorming what else brown might clump under the radiator cap that could be better news.
The brown stuff you are probably seeing is rust. Flush it out.
As far as Bars Leak, it's fine if you put it in correctly. One time I was in Green River, UT, and I needed a hose. The place has like 1000 people and there is nothing, I mean NOTHING 100 miles West or East of there. Not even a gas station. Naturally they didn't have the hose I needed. Let the engine cool overnight, and Bars Leak (or Silver Seal) in the morning. Made it all the way back to Nebraska. As a matter of fact, I never did replace wherever it was leaking. This was about 10 years ago. Also really any of the auto mfr's have something similar from the factory.
Don't know if your vac reading is correct for the cam. Verify that the o2 sensor is working. You can swap sides if you don't have a scanner to monitor the PIDs.