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Took the speedster out today for nice run.  Outside temp was 75*.   Oil temp climbed to 220* but CHT was only at 280*.  I have an external oil cooler mounted under the driver side read seat.  It kicks in at 180*.  The engine bay is all sealed up.

I am thinking about getting the DTM shroud, welded fan and smaller 356 alternator pulley to speed up the fan.

Any other thoughts or ideas?

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I'd move the oil cooler to the driver's side rear fender well. Hoses are cheap.

A DTM is $575, plus freight (which will be at least $100). A welded/balanced wide fan is $110, and a 356 pulley will be $100 as well. It gets really, really spendy out in the deep water.

Do all that, and you'll end up moving the oil cooler anyhow. A DTM, etc. is good for cooling your heads. The only thing a DTM has that any other shroud does not is a T4 oil cooler on the stand, and you can do that with any tin with a bit of modification.

Just move the cooler.

Last edited by Stan Galat

Anything goofy on the motor, like a chrome fan shroud, or lack of engine bay seal?

What oil cooler do you have?  Some of the aftermarket alternatives, like EMPI, just aren't as efficient as the expensive ones like Setrab.

Make sure you've the right sender/gauge combo.  Too often I see a mismatch there, which gives false readings.

If you are 100% sure that 220 is your accurate oil temp, And you have a good quality oil cooler (like our stock Setrab) then you'll need to start looking for a physical cause.  I've run aircooled with a simple Setrab single fan pack and once the cooler fan kicks on, oil temps drop to 190-200 and stay there...

You don't want to see anything above 235, but damn Im surprised you have such high temps with such a low ambient and such low CHT temps.

I won't discourage you from moving the fan into better airflow, as it certainly won't hurt, however the reason we use the Setrab is that it is highly efficient even when mounted out of direct airflow such as the low pressure location under the rear "seat" area.  It's worked perfectly in that location 100s of t times, so even if you do improve your oil cooling by relocation, I'd still be looking for the root cause.

Has something changed?  Did you have the engine out for service and and now oil temps are an issue- the rag/paper towel in the fan (or Alan's rag left on top of the cylinders- that must have been a fun 1 to track down!) can drive you nuts trying to figure out what's going on.    You said "the engine bay is all sealed up"-  what's the airflow into the engine compartment like?  An engine starved for air will overheat like there's no tomorrow.  Put a remote thermometer in the engine compartment; anything more than a few degrees above ambient will tell you there is an airflow issue.  A simple test- drive around until oil temp gets almost to the point of being unreasonable, stop and prop the engine lid partly open and continue on and note the result.  Lower temps means you need to get more air to the engine.  A member (can't remember who) did this with a pool noodle a few years ago, discovering that even on a short drive down to the beach his engine could be running cooler- what will happen at continual highway speeds?

As Carey suggested- look for the root cause.


Sorry I have to log out last night to take care of the honey-do-list.  But to answer some questions.  The motor has always seem to have high oil temp.  End of last year I installed the remote cooler.  That helped a little bit.   This morning I checked the shroud fan for debris and found none. 

I do think the engine bay gets hot. The shroud get to hot to hold your hand to for more than a few seconds.  I will try driving today with a thermometer in bay.  Once the oil heats up I will pop the lid and drive to see if temp falls.  It should be a good day for this test as temp is going to 80+ today.

I will report back my findings.

As always, thank you for the guidance.

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