oil temp sender location ?
 

Should I have my oil temp sending units installed before or after the cooler.This would indicate two different temps depending on location.
The way I have it plumbed now is after the coolers due to simplicity of hose routing.The coolers are Hardin marine with themostats and are suppose to maintain between 190 and 230 degrees.

thanks

Bob

I have them in the oil filter brackets.

Many schools of thought on this. Most seem to put the sender right in the filter pad. That is where mine is. Probably best to have the sender in both locations. My thought is that you could have the sender sort of removable and check both locations. Once you have a baseline if either varies much you know something has changed and needs attention. Once I got my sender in and t-stat installed I have never seen much of variance. Always right around 220 and 240 at WOT summer. A little cooler in spring and fall water. If you checked both locations and established a baseline the pan may be the best location as you can assume the cooler will always be doing a consistent job but something may be going on in the engine to raise temps. Any problem with the cooler would show up in water temp but perhaps not to as great of a degree. You should get lots of advice and opinions on this, both locations have their merits.

For the pad location you can make one real cheap. Just go to Wally World and buy a digital candy thermometer and drill out a brass plug the same size. Fit the thermometer in the plug and JB Weld it in. For 12 bucks you get a high and low memory. Put the on line gauge in the pan and spot check the pad.

Mine is going in the remote pad also. Blue Thunder has his there too I think. He suggested that location to me.

You know me Bob, not a mechanic. But, shouldn't the sending unit be located before the cooler? That way it seems you'd know what the oil temp is before cooling. However, if the unit is located after the cooler, it seems like you'd find out fast if a cooler / Tstat failed. Just "shoot'n from the hip" here, now I've confused myself again :o(

When do you plan on firing those new puppies up?? How about a pic or two.

Bill

Bill,
I have thought the same as well. Oil is pretty dang thick until you get it up to 190 or so. I like to have mine on the pad (besides until the engine comes out I can't put it anywhere else) so you know your oil is up to temp before hammering it. However as I said before once you get the baseline you will know. If all is well in the engine and you feed it oil at 200 it should be fine the rest of the way through. If it comes back at 240 and you have a HUGE oil cooler it may be a touch to hot in the pan. Look at it this way, if your cooler was monstrous and your oil was 300 in the pan it still could be cool after the cooler. That is my logic for spot checking the pan and monitoring after the cooler. Make sense or should I go get a beer and think about it?

BD,

It makes sense to read it coming out of the engine before the cooler .The oil should be at the highest temp @ this location.

Kid ,

Hoping to fire the engines in a couple more weeks. The cylinder heads are still in the shop waiting on springs.

Bob

BadDog, How fast, or at what rate does the oil in the system circulate? I did not know {or didn't think about} the oil would stay in the pan long enough to get much warmer than that which was circulating through the system. But it makes sense that it would get warmer, if there is a large volume, or accumulation of oil in the pan. How would you get a sending unit to the pan? Drill and tap, or maybe stick it in the pan drain location?

What you say does make sense. For sure, go get beer/s. But not to think more, but as a reward for thoughts already expressed. As always, I'll have JD ;)

My stock pans have a pipe thread plug on the left side of them. Not sure if there low enough to always be submerged in the oil though. If they are you could place a sender there.

Check the oil temp in the pan... then if you are having a problem with the engine... you will see a spike in the temp in the pan... don't measure the oil temp after it has gone through the cooler... won't tell you a damn thing other than the tempurature... the whole point of having gauges is to moniter what the ENGINE is doing... If you are starting to run lean... you will see the temp rise in the pan... you won't see it in the filter pad.... or after the cooler.

Maybe Reed knows how many GPM an oil system flows. I had asked that question several times before and never really got an answer. Yes there are variables but are we talking 10 GPM at 5250 or 20 or what? Don't really need to know, just curious.

I don't know either to be exact... but I can get the figures for an external system like what is made by Aviad. They are near me... I can call... The variables are bearing clearance. tappet type. cam bearing clearance. then... you have to factor in how much flow is lost because of restriction through external hoses. Plus you have to figure what the pump was originally designed to flow.. how much is going through the bypass. how thick the oil is and at what temp... Melling makes a "high flow" pump... but you can't flow any more oil than the passages will allow... Plus... the clearances don't ever change... but the flow increases with rpm's.. so at one point... there is probably as much oil coming out of the bypass back into the pan as there is going to the bearings.

I had a sender in the stock location, at the pad, and then another on the oil t-stat housing. That way I could measure temps both before and after the cooler. I also had a switch under the dash that would switch between the two senders, yet use the same oil temp dash gauge.

My question to the folks who say the temp at the pad doesn't spike or as some will tell you it can be 10 degrees cooler than the pan is;

Why do you need an oil cooler then cause ,seems 2 feet of oil line is enuff to drop the temp the 10 degrees on its way to the pad and so the 2 deet back from the cooler would then drop it another 10 degrees, whala 20 degree temp drop no oil cooler needed so just get rid of your coooler it is apearantly doing nothing.

I have never seen any credible evidence that the oil temp at the pad is signifigantly different then the pan. It does spike and follow the temp in the pan, simple laws of physics if the temp in the pan spikes 5 degrees the temp after it comes out of the pan thru 2 feet of oil line will also spike 5 degrees.