I am considering purchasing a turbo temp monitor, but would first like to know how the Engine Oil Temp reading being sent through the OBD II connector on my 1999 F-350 7.3 Power Stroke may relate to the temperature at the turbo?

How much of a difference is there, plus or minus, between the temp I read as Engine Oil Temp and the temp of the oil cooling the turbo?

Thank you

 

It reads oil temp at the back side of the HPOP reservoir.

Your oil temp in your HPOP is likely more then your turbo. I don't know for sure, otherwise they would put the sensor in a different place?

 

The monitor I was looking at calls for a thermocouple probe to be installed post turbo (exhaust down-pipe). When the probe reads 300 degrees the monitor turns off the engine.

Given the statement above from Layson, am I correct in thinking that if my oil temp reading through the OBD II is less than 300 degrees, the temp at the turbo is also less than 300 degrees?

 

If your engine oil temp at the HPOP hits 300 deg, you've got much more to worry about than a turbo. Engine coolant is designed to keep the engine cool. Oil around the EOT sensor will likely always be below 200 deg F.

If you're interested in a turbo cool down timer, that basically has to do with the fact that the turbo shaft spins MUCH faster than any other engine component, so allowing the shaft speed to slow down and cool with a good flow of oil will extend the life by preventing coking or degradation of the oil film around the shaft.

In my opinion you'd be better off watching a clock that watching EOT. Of course it's been a really long day and I've had a few, so if I missed something here, someone please jump in and correct me.

 

He's talking about EGTs hitting 300, Chris.

The rest, I don't get either.

 

Are you sure? He mentions reading the temp in the down pipe and makes the following comment:

Sounds like he's curios about the oil temp at the turbo. Perhaps the 300 deg EGT number wasn't meant to be related to the oil temp question and I just misunderstood.

 

Yes, little confusion here... Engine Oil Temp and Exhaust Temps are not related. You want to install that pyro post turbo, right in the manifold.

 

In the manifold would be "pre-turbo".

 

yeah.. thanks for that. Been a long day... hahaha

 

Here's a link to what I am thinking of getting: ISSPRO Turbo Temp Monitor R4130 at DieselManor

It says "Standard shutdown temperature is 300° F" which from the context I take to be exhaust temperature. The statement is also made "By shutting down in a cool condition, deposits are reduced and turbo life is increased." I take those "deposits" to be coking of the oil cooling the turbo.

I was wondering if there is any correlation between the EGT post turbo, the temperature of the oil cooling the turbo, and the engine oil temp shown on the OBD II port.

 

Absolutely zero correlation whatsoever.

If you want a turbo timer, that's fine. But I personally won't waste my money on one. Reason being is I don't think it's needed on a diesel. First, these engines run at much lower EGT's than gassers do. Second, they pump much more air through the engine (with much leaner fueling) than a gasser, so EGT's fall much quicker once the truck is at a stop. Third, oil today is much more resistant to coking than years ago, so it's actually very rare to see oil coking in the turbo on a diesel truck. Yes it's more common on a gasser, but it's extremely rare on a diesel.

That's my 2 cents.

The only thing I ever do is watch my pre-turbo EGT gauge. Once it drops below 400 degrees, I shut the engine off. It doesn't take long to cool off to those temps, and I rarely have to wait for the EGT's to fall.

 

Pocket, Thanks. Good reasoning behind not needing one.

 

Well said Curtis.

The only reason I use one is because it is nice to not have to wait or if I'm at a stop I can pull the keys, leave it running and the A/C on.