Fixed the plenum no problem there but there's still an oddly low oil pressure reading on the gauge occasionally drops below 40 any ideas why?

 

Oil pressure sending unit. Check connection on it and/or replace it. I would put a mechanical pressure gauge on it to see what the pressure really is.

 

slight drop in oil pressure at idle (vs higher rpm) is normal.
and anywhere in the normal section 20-60+ is considered ok.

drop in oil pressure to 0 is not normal, and likely not even really happening, unless accompanied by valve train ticking or clicking.

my oil pressure reading went bananas yesterday too. out of the blue, it began dropping to 0 at idle, coming back to 40 at 1500 rpm. turn it off/recranked - still did it. went ahead with oil and filter change since it was due. did the "gauge test" by turning ignition on while holding in odometer trip meter (98-01 only maybe??). that was normal. now oil pressure is reading higher than normal, in the 50-60 range. so i don't know wth is up with it.

 

Did you confirm the reading with a mechanical gauge? I would do that first or just replace the oil sending unit if you haven't done so already.

Other than that, when my sister bought a used 360 off of craigslist for $600 when her husband forgot to check her oil and she toasted a main bearing, anyway I put the new motor in and from nearly day one her Ram randomly dropped pressure like you explained, one minute great pressure, next minute none. Unfortunately she told me about it when it was too late, I dropped her pan and her oil pump was full of permatex & gasket shavings from a previous owner who went crazy and didn't bother to clean the engine after doing a plenum gasket. I'd imagine he just dumped the crap in the motor because he was too lazy to clean his mess up and that ended up clogging up in the crazy small stock oil pickup tube. Eventually this all lead to her toasting another front main bearing though not as bad as the first time lol. When in doubt drop the pan,change the pump for $25 buy the $10 new wider oil pump pickup & rest assured before you have this happen to your Ram.

But first check if your sending unit is or isn't full of $hit on its readings. When in doubt, always trust your sending unit and discontinue use of your vehicle till you confirm the problem.

Nope not a drop, other than my exhaust manifold on #7 cylinder had some oily wetness around it, but it would burn off before leaving any drops on the ground or anywhere else other than the head. The oil burn off smell was horrendous. 3 of the valve seals I took off were obviously cracked down the center and the others were most likely worn but not as obvious. So far since then I've gone about 7,000 miles without a drop being used (and yes I'm due for an oil change lol).

 

Thanks bud got all that figured out but now she's all of a sudden over heating and I lost all inside heat,my first instinct was that it was the thermostat but I just put a brand new one in last week when I did the plenum and plenum gasket change, it's almost like I'm not getting any coolant circulation at all

 

Low on coolant.

 

It's possibly air trapped behind the thermostat. I would remove the upper hose and thermostat housing. Next, Drill a small 1/8 inch hole in the flat part of the thermostat. This will allow air to bleed past the thermostat, and into the upper hose.

The thermostat will NOT open with a pocket of air behind it--first hand experience.

 

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I just had the same problem after doing my plenum yesterday my engine would not get up to temp so i yanked the thermostat drilled a small hole and it warmed right up just needed to get that air out of the block worked great


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Thanks bud that was it i went and got a dura last that had a pre drilled hole from the factory and it completly solved the problem she's running cooler than ever