Coolant temperature question

[haydenm315]

Recently I installed mechanical water temp and oil pressure gauges. What is the correct temperature for me to read my oil pressure? What temperature is the thermostat set for in a 93 mtx? Is it 192F? Is this when the car is warmed up, or is >=150F considered warmed up. I'm trying to decide if I should install the rod bearings I bought now.

When the engine is cold, oil pressure at idle is 55psi. When accelerating slowly out of my neighborhood cold, I show 75psi. When the car gets in the 190F range, idle drops pretty low on my gauge. I know it's >5psi. The oil pressure light isn't flashing and never has at idle. It doesn't help that my gauge doesn't have the best dial reading between 0-10psi. 0-5psi is not easy to decipher. With the engine at 2k warm, I'm showing about 20psi. I searched around the forum for some pointers. THe helms says that the minimum allowable oil pressure is 12.8psi, however the light only flashes under 5, and some threads say that between 9-11 psi is just fine. I do think my engine is a bit loud at idle. One of my bro's cool hillbilly friend said something about hearing my cams. Other than tickign some at idle, it runs very smooth dsa4e5 w54 <- just fell asleep at my computer. I woke up because I was falling and hit the ground. cya

 

[DHMag]

on new bearings, running 5w30 oil, my cold idle oil pressure is 55-60, depending upon ambient temperature. anywhere from 202 to 218 degrees on the water temp gauge, my warm oil pressure is 10/10.5. this is on a 130K mile motor.

 

[haydenm315]

DHMag:
on new bearings, running 5w30 oil, my cold idle oil pressure is 55-60, depending upon ambient temperature. anywhere from 202 to 218 degrees on the water temp gauge, my warm oil pressure is 10/10.5. this is on a 130K mile motor.

My warm pressure is what concerns me. At 200, my oil pressure gauge is just a little bit past 5psi. I wonder how accurate an auto parts store's oil pressure gauge is. How accurate is the stock oil pressure sender? I'm using castrol gtx high mileage 10w30 that was just changed a few hundred miles ago. I'm almost itching to do rod bearings, but I'd like to know that I'm in need of doing them first. I put a scope up to the pan a few months ago and all was quiet. I've already got the bearings, I just need the pan gaskets, and a free afternoon. I do all of my own oil changes and have used mostly high mileage gtx, but have also used amsoil 10w30 and the dreaded mobil 1 synthetic 5 w 30. I like to drive my car hard at times, and definately want to prevent a rod bearing catastrophe. I've owned the car since 77k and am now showing 96k.

 

[haydenm315]

Is there a way to determine low oil pressure with a gauge, other than hot at idle? My gauge loses sensitivity down low. It was probably made for high oil pressure v8's. My cold idle is very similar to DHMAG. If my bearings were indicating excessive wear, would my car have significantly lower oil pressure at cold idle? My car has hardly ever gone above 200F. I guess I have to run the idle test on a 90+ degree day while the car is sitting still. I wonder if my computer will show me the digital readouts of oil pressure and temp? It can read many stats in realtime on my 93 tempo. I've never tried it on the sho.

 

[SHOZ123]

Just as a way to measure the pressure when hot and low you can get a gauge with better resolution and a lower peak pressure reading. I would get a tee pipe, a shutoff valve and an air pressure gauge that reads up to 15 lbs. Only open the valve when the oil is hot and pressure is lowest.

 

[haydenm315]

DHMag:
on new bearings, running 5w30 oil, my cold idle oil pressure is 55-60, depending upon ambient temperature. anywhere from 202 to 218 degrees on the water temp gauge, my warm oil pressure is 10/10.5. this is on a 130K mile motor.

My cold pressure with castrol gtx high mileage 10w30 is 55-60 depending upon ambient temperature. I'm afraid my gauge is not accurate below 10psi. What a crock. That's what I get for buying the salvo special. What junk@!