nwcrob

does anyone know what oil temp a 502 should run at

the water temp guage is normal at about 160 but every time i go out the oil temp seems to be getting hotter but water temp stays the same

anybody help

Mr Gadgets

NW.. oil temp in a marine motor should be 220*-240* F. Check to see if the oil flows through the cooler opposite the water flow. Make sure it is all going through the cooler..

Hope this helps.
Dick

Bigsbetter

Oil will vary with engine load and rpm. If you're running WOT for 20 minutes ,the oil temp. may get up to 325 degreees or so. That's fine as long as it cools back down when you start cruising again.

Mr Gadgets

I personally don't like to see it go much above 260* on a long run.. And I dont run it hard till I see 180*.. But that is just my preference.

cloudmaster_321

I bought CP Performance's oil thermostat. It's a 212 degree thermostat. I thought i was doing the engine some good to make sure that at idle the oil temp would still get up to temp. Now i'm hearing that 212 isn't hot enough to burn off the condensation, so i don't know what to do now..................

stevesxm

212 will work . you need to have something over 200 ( 220 is better ) all the time and not to exceed 290-300. the oil cooler should be sized such that you run 250/260 at wot for as long as you want. if it continues to climb the harder you run then the cooler is too small. if you find yourself operating your boat such that the oil temp is too cold ( extended cruising or whatever) then you need to do just what you are doing to keep the temp in its nominal operating range.

cloudmaster_321

I was thinking about this as well this morning, and i agree. Mercruiser engineered this motor to run with that cooler. I would imagine that the engine oil temp will climb above the the 212 mark when in extended high rpm's, but would never get below the 212 mark after extended idling or slow speed cruising. 212 is just the baseline.

stevesxm

thermal equilibrium is really important in all motors. for the metallugy to work properly and for the lubricants to work properly , the correct operation temp ranges must be maintained. can you run them too cold and get away with it ? sure. the same with running it too hot. the motors are tough and will tolerate a fair bit of abuse.... but the question would always be " why would you want to ?" the correct nominal operating temps are well known and understood. the variables are always the same... how cold is the water you are using for cooling ( delta T ) and what is the thermal load you are putting in. the trick is to size the coolers properly for your expected loads and maybe go a bit bigger for those times when you want to beat on it and just run good thermostats on both the water and oil to keep the temps where they should be. if you do that everything lasts longer, seals better, and remains cleaner.

Philm

I have been having sort of the same problem. The oil temp will hover right around 180* while cruising at 4300RPM ( JC Performance 598ci 800hp N/A) but this past weekend, running at WOT it would shoot up to at least 280-300* in a matter of 30 seconds. I was Thinking that this was way too hot so I never held it there to see if it would keep climbing. Dropping the RPMs back down to cruise speed would see the oil temp go back down fairly quickly, within two or three minutes, to 200* or less. Water pressure is good at 18-20psi at 6000RPM, water temp doesnt even register. I have a feeling that the cooler may be clogged up some after an impeller ate itself a few weeks back, but I did backflush a ton of rubber out of the system. I guess I will have to take the cooler off and look for light.

Basically, my question is: Is that too high of an oil temp too quickly? I am not sure what the Thermo is for the oil. How high of an oil temp before I should really start getting worried?

stevesxm

yes. it tells me a couple of things... first that you have inadequate air flow thru the engine compartment and second that the cooler sounds way to small for the thermal load. getting adequate fresh air thru the engine compartment will go a long way towards stabilizing those temps but in the absence of that, it implies that your cooler is sized for cruising speed. get a bigger cooler and a thermostat. you are doing your motors no good at all runing 180 deg oil nor do you want to be limited in your ability to use some revs by the inadequate oil cooling sytem.