I have been incognito for a while now, just reading alot in OT and somewhat in the 5.0 section. I decided yesterday (after mos of not touching the mustang) that I had some time to kill and a lil money to burn.

First, a recap: Last may/june, I decided to rebuild the motor because it was dying off on oil pressure at idle and all the years of cop abuse/nitrous from previous owner really did a number on this engine, not to mention the broken head bolt. Built a little mild 306 using the stock block and such, nothing major. I completly redid it all (machine work, overbore, new pistons, turned crank, gaskets bearings etc). I fired the engine up at the end of june and noticed oil pouring from between the block and the oil cooler. I tried tightening the oil cooler bolt but it didnt help it still poured oil I ended up having to use a oil filter gasket on the cooler and that resolved that issue. I parked the car at the end of june and let it sit.

I drove the car maybe100 miles since the rebuild everything runs like a champ it has good oil pressure and all but the last time I drove it was mid december when my daily driver took a **** on me and it was my only means of transportation. I noticed the oil pressure falling just a bit but wasnt too concerned. So yesterday I got this hunch that the oil was older than 3 mos old and needed changing (had valvoline oil in it). I drained it and it looked very frothy (almost like it had water in it but it wasnt milky) it looked like it was on the verge of being sludgy. and there was a goldish tint to it and it reaked of exhausted fuel. I have 24lb injectors on the car which I know are overkill for the mods that I have and there is alot of fine tuning still left to do. And the car runs rich as hell

so my questions are as follows, 1. Could it have just been old oil, Has anyone ever seen old oil and what does it look like, 2. Is it possible that there is coolant leaking through the cooler because I overtightened the bolt (those with the cooler will know what I am talking about)?, 3. Is this just what oil that was used to break in an engine is supposed to look like? 4. Will running rich cause this smell? 5. Is there a way to test the oil for the presence of coolant?

I changed the oil in my truck to (new daily driver 2002 silverado 5.3) and it looked normal for 3k mile oil (black, thinned out, slight smell of exhaused fuel) and that is what I am comparing it to. I have always changed my own oil and I have never smelled the exhaused fuel smell as bad as I did yesterday when I changed my mustangs oil.

 

oil smells like that when you are breaking in a motor.

the gold-ish tint you are describing is bearing material. Its nothing to be worried about since ALL new motors do it.

and the fuel smell, again normal. when you first run the motor, more fuel is prone to leak past the rings until they have fully seated and fitted to the cylinder walls

 

why would the oil appear frothy and almost sludgy... it almost looked like a melted chocolate milkshake

 

Breakdown, and moisture. That's my take on it.

 

What pump/pan setup are you using? Maybe the pump is cavitating and aerating the oil. Or the oil just got beat up real hard and is breaking down. Oil gets worked over pretty good when you're breaking in an engine.

 

you are either leaking coolant from your intake manifold gasket (very common) or something is cracked.

Ive never heard of oil being that bad from condensation

 

Because it was dark, you missed, and accidentally fvcked her in the a$$...

 

ok I ran the engine got it to 180 degrees and then drained the oil and kept pressure on the cooling system, and pulled the cooler off there was no coolant draining from the oil pan. Then I looked at the old oil that I drained out and it looks fine... I was just over reacting I guess. Like I said the old oil only had maybe 100 miles on it and it still had the gold oil color to it and you can see the bearing material in it that adder was talking about. Other than that there is no obvious signs of problems. There shouldnt be I took my sweet precious time putting this engine together. torqued every single bolt to spec and in the correct sequence according to the chiltons manual.