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What temp oil

R

rayb

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"Sorry for going off topic, bu

"Sorry for going off topic, but this is the most popular section of the board and by posting here I figured I had the best chance of a response.

In the case of my FWC block only V8, the mechanics advice was always to run it at 170F with a 160F thermostat ( which I did ) as the oil needs to be at least that temperature to disperse the contaminants, and condensation etc.

I fitted a new double pass heat exchanger and it has dropped the temperature to 150F, regardless of how fast or hard I run it.

I asked the mechanic if we should start to play with the thermostat to get the temperature back up, and his comment was, " Well if it was a raw water cooled motor it would run at about 150F with a 140F thermostat." So we will leave it alone.

Does this mean that the oil never does it's job on RWC motors, or is this whole oil thing smoke and mirrors?

I currently use synthetic 15W50, oil pressure is 65 psi @ 3000RPM and about 30 psi at idle 700 rpm.

I would appreciate any comments as to whether I should get the temp back up, or just do what I have been told.

THanks in advance for your time to reply.

Ray"
 
"The 150 F. temp. is a measure

"The 150 F. temp. is a measure of the coolant as it exits the intake manifold via the T'stat. Is the T'stat working? Best way to find out is to test it with a string, DEEP pot of water and a thermometer. Heat the water to open the T'stat, grab it w/tongs and insert the string and immerse in cold water. Cool the hot water to about 120 F. and start to heat the water again and hang the thermometer so it does not touch the bottom of the pot and hold the T'stat the same way. When it drops off the string read the thermometer.

Coolant temp. can be 100 F. to 400 F. lower than oil temp. Get an infrared laser temp. gun and check the temp. on the oil lines and filters and also the T'stat base and top. The gauge will tell you the temp.

My RWC 4.3L runs at 140 F. which is the T'stat rating. My oil temp at the filter is close to 200 F. using 15W40 Shell Rotella. I switched to Mobil One 15W50 when winterizing which should allow the engine oil to run a little cooler while the water temp. will be based on the T'stat."
 
"Thank you for the reply Guy.

"Thank you for the reply Guy. The thermostat is working, I failed to mention that I have two bypass holes drilled in the flange of the thermostat. So it appears that the very efficient heat exchanger will keep the temp at 150F, and the thermostat may never open.

Thank you for the point about the oil temp. So I guess it doesn't really matter whether the coolant temp is 150 or 170, the oil temp is going to be much higher anyway.

I have an ifra red temp gun, and will run it over the motor next weekend.

I had always assumed ( which never pays) that the coolant temp was also the temp of the oil and the metal in the block, obviously wrong now that I think about it,such things as combustion chambers must of course be at much higher temperatures than the coolant at the thermostat.

As I say, learning, learning learning all the time.

Ray."
 
"Are the bypass holes in the h

"Are the bypass holes in the housing flange or the T'stat? Are they there from the factory or did you drill them and what reason? If they are not factory holes in the housing, you can plug them with an epoxy like JB Weld.

Your T'stat is opening sufficiently and your heat exchanger is working well. After flushing the block, fill the cooling system with 50:50 premixed Prestone or Peak antifreeze. Test your pressure cap to insure it's working. It will raise the boiling point from 212 F. for water to about 240 F. It also is a good rust inhibiter."
 
"At the time I replaced the th

"At the time I replaced the thermostat, a marine stat was not readily available so I used an automotive which has a smaller aperture both in diameter and height when fully open therefore to ensure sufficient flow I drilled the holes in the flange of the stat. The result was that with the 160F stat it took a little longer to warm up, due to the bypass holes, however regardless of high revs etc it maintained a steady 170F all day, with the old heat exchanger.

As stated, installing the new exch has dropped the temp to 150F, and by virtue of the bypass holes it will probably never get any hotter.

So, should I just leave it like this, is there any downside to running at 150F ?

I can of course just get a 160F marine thermostat and drop it in, but what is the point if 150F is OK. Besides I have a beautiful paint job on the motor, and hate the thought of getting coolant over the paint job and trying to dry it out of all the nooks and crannies around the intake manifold.

If your advice is to replace the stat, well I will just do it. Thanks so much for your time Guy.

Ray."
 
"Ray:

If you are satisfie

"Ray:

If you are satisfied with your engine performance then why split hairs over the 10 F. difference. If you check it with your infared temp gun and see that the oil is hot enough to cook off any moisture from combustion, then leave it alone. Change it when the temp starts to climb above 160 F. There is something about a nice clean engine, isn't there?"
 
"Guy,

Thanks for your advic

"Guy,

Thanks for your advice, I will just leave it be.

Just to make you gents a little jealous, we are just going into summer (1st December) and the beginning of a great boating season over Xmas and New Year, here in Australia.

Best wishes to all.

Ray"
 
"I saw on the news tonight tha

"I saw on the news tonight that scientists have discovered the ice on south polar cap is actually a giant iceberg and it is drifting northward toward Austrailia, will be w/in 1000 kilometers and will cause permanent winter w/in 3 years w/temps of 0-5 deg. C. Enjoy your winter.
rofl.gif
"
 
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