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The oil temp indicator is about 1/8" from the "pegged position after a semi spirited drive here in Phoenix in 77 degree temps.  The oil cooler fan was on after I parked and shut down the engine.  Engine is 2110cc with 40 IDF Webers, just about 100 miles on the car from new.  I would think in this weather the needle would be in the middle of the range, any thoughts?

Thanks

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How do you know what the actual temp of the oil is?   If it is a "band" gauge with no numbers on it, then you don't have a clue.  What you need to do is get a candy/baking thermometer with a long ( 8" - 10" ) probe (the same length as the bottom of your dipstick) and a range of 175ºF - 250ºF.  When you've finished your "semi-spirited drive" on a freeway, hop out, pull the regular dipstick, put the candy thermometer down the dipstick tube and see what it says - Then you'll know what the oil temperature really is.

At 77ºF out and after a fast freeway run, the oil cooler fan should be running - that's normal.  Besides calling the builder of your car, you need to determine what the oil temp is for different needle positions on your gauge so you'll know what's going on, like cold, after a five-minute warm-up and freeway temps.

I suspect that you might have a temp sensor on the engine that is a little off from what the gauge is expecting to see - that's pretty common with the parts we have to deal with these days, and you may only have to change oil temp sensors (they're cheap).

But first, though, find out what oil temp you really have and don't rely on a questionable gauge.

The oil cooler fan was on after I parked and shut down the engine.

This a common error by many installers of external oil coolers. The installer wired the fan to a constant hot wire that is controlled by the sensor that causes the fan to come on at whatever temperature the sensor is designed to come on at. I know that is confusing so here's another attempt. If your fan controller is a 180 degree sensor switch and the power wire that it controls is constantly hot your fan comes on when the oil gets to 180 degrees and will run even with the engine turned off. The fan will turn off when the oil goes below 170 degrees, IIRC. If the oil sensor switch is a 190 degree switch the same thing except the oil will be hotter before it turns on.

The problem with this is you are only cooling the small amount of oil in the cooler. The oil is not being circulated through the engine so there is no real benefit to having the fan turning when the engine is off. Have it wired so the fan shuts off when the car is off.

And I'm in agreement with the other guys. Find out the real temperature of your oil and its most likely a faulty oil temp sending unit.

My fan powers "hot" through the oil temp switch (like described by Robert M above), even after ignition switch is turned off.  At one time I considered rewiring the fan though an ignition circuit but have since decided I'm better with letting it run after the engine is turned off (and not because I think it sounds cool).

Over the past 15+ years/35000 miles I have replaced my horizontally mounted fan twice.  And based on the durability of the first two fans, I think my third fan has about reached the term of its life expectancy.  These have all been the standard fans found in the familiar VW parts catalogs.

As a matter of conscious habit, when I turn off the engine I want to hear the fan wailing in the back.  When it starts sounding wimpy, that's my clue it's time for some routine replacement maintenance.

It doesn't bother me that the fan stays on after the ignition is turned off (which is also typical of many modern cars).  I much prefer knowing that I don't have a dead fan before blasting off on a long drive on a hot day.

Good to know these parts are made so poorly.  Was yours from Vintage Speedster and was it billed as an aux. oil cooler?  I ordered toe aux oil cooler that normally comes with/required the A/C option because I live in Phx and the 2110cc may run a bit hotter.  The fan I have is behind the shroud, is that indeed the aux fan/oil cooler?

Thanks for your help.

Randy

RS-60 mark posted:

My fan powers "hot" through the oil temp switch (like described by Robert M above), even after ignition switch is turned off.  At one time I considered rewiring the fan though an ignition circuit but have since decided I'm better with letting it run after the engine is turned off (and not because I think it sounds cool).

Over the past 15+ years/35000 miles I have replaced my horizontally mounted fan twice.  And based on the durability of the first two fans, I think my third fan has about reached the term of its life expectancy.  These have all been the standard fans found in the familiar VW parts catalogs.

As a matter of conscious habit, when I turn off the engine I want to hear the fan wailing in the back.  When it starts sounding wimpy, that's my clue it's time for some routine replacement maintenance.

It doesn't bother me that the fan stays on after the ignition is turned off (which is also typical of many modern cars).  I much prefer knowing that I don't have a dead fan before blasting off on a long drive on a hot day.

How long will the fan run for after turning the engine off? And you know that all you're achieving is cooling the oil in the cooler and not in the lines, sump, or engine itself, right?

To add to Al's explanation.  The fans on modern cars are for cooling the couple of gallons of water in the front mount radiator.  In modern cars there is more coolant in the radiator than what's in the engine.  When the car stops moving there is no airflow thru the radiator so heat builds up in radiator and the fan comes on.  That's different than a fan on an oil cooler which holds only maybe a quart with the engine having the bulk of maybe 3 quarts.

This is what you have - there is a remote oil cooler which adds to amount of oil in engine and cools it.  Often an electric fan is added to increase air flow thru that oil cooler.  A thermostat is added to route cold oil past the oil cooler and could also trigger the fan to turn on.

The key is does the fan turn on when the engine warms up to 180 degrees.  If it doesn't and the cooler is out of the main air flow - the cooler doesn't cool much at all.

Bolt On Full Flow Oil Cooler Kit- retains stock cooler

Randy  --  Actually, I don't have a speedster, rather a mid-engined spyder (that I built myself).  So I wouldn't be able to give you speedster specific technical information by- manufacturer.  But as a generality, all of us Type 1 folks share similar engine/trans mechanicals and experiences.  I have a 2332, and engine cooling is a big deal.

As far as parts source, pick any of the familiar VW on-line parts catalogs; the fan they show with the usual 96 plate cooler is the one I would have chosen.  [ Edit:  Which is the same one Wolfgang pictured in his post immediately above. ]  My guess is it's the same kind of fan nearly all of us have. Although there are more expensive and presumably better alternatives available, I think the "standard" fan is adequate and easy/economical to replace if necessary.

I think my fans fail as a matter of degrading over time due to the high temperature under the hood.  But that's just an opinion.

ALB  -- My fan runs until the temperature of the metal sensor switch drops below the cutoff temperature.  My sensor switch is not under the direct flow of the fan, so the time it takes the fan to turn off is related merely to ambient cooling of the sensor switch and how hot everything was to start with.  On the hottest of the hot, maybe 5-10 minutes.  On a cool day, maybe 1-3 minutes.

Your point is well stated, the cooling radiator doesn't hold a lot of oil.  So, "pre-cooling" that small amount of oil between engine runs Is probably not imperative.   On the other hand, it does't hurt either.  As mentioned, my motive for letting the fan run is not specifically to cool the oil in the radiator (it can cool by itself), rather; I want to hear the fan wailing so that I know it will be maximum efficient when it comes time I do need it most.

Last edited by RS-60 mark

I am installing a Derale remote oil cooler and have red many of the archives concerning the same. I am also using a thermastatic inline switch. Also Derale. It seems most are saying the fan should be connected to an ingnition control on off rather than directly to the hot side of the coil.

My question is since due to my thermastatic control switch the fan will not come on when I start from cold. So does connecting direct to the coil hurt the coil? Does it affect the engine spark? If so is it only at start.

I would rather switch it at the coil than running a wire all the way to to dash under the car. Or is there a better way to get the wire to the front?

As always thank you for your responses.

Paul

I ran mine from a hot wire off the starter lug and added a 15 amp inline fuse for good measure. No switch but if I ever do add a switch it'll be on the ground circuit: ground it to the chassis where the switch is and run one wire back to the fan.

The reverse light is powered off the coil (another in-line fuse there too). Much smaller draw and of course it's lit only intermittently.

.

My kindergarten teacher, Mrs. Zomack, always told us that motors should be controlled by relays, especially if they draw a few amps or more, and, on balance, she has been right about most things.

Also, long, high-current cable runs are wasteful, so Ed’s idea of using the starter lug for power is a good one. I think I’d site a fused relay as close to that as possible and trigger the relay with the thermostat switch.

If you want some entertainment, have the relay light a small LED somewhere in your instrument cluster, too, so you know when the fan is on.

@edsnova posted:

I ran mine from a hot wire off the starter lug and added a 15 amp inline fuse for good measure. No switch but if I ever do add a switch it'll be on the ground circuit: ground it to the chassis where the switch is and run one wire back to the fan.

THIS ^^^

I pulled power for my fan from the rear-mounted battery in my Spyder. There is a fuse at the battery, then about 2 feet to a relay mounted right on the fan. The fan has power all the time, turns on and off when needed. All by itself, with no intervention.

IF you wash the car, try to keep water away from the relay. One time I was a little exuberant with the spray and flooded the relay. The fan wouldn't shut off until I unplugged the relay.

After this happened, I drilled a 1/16" hole in the bottom of the relay to let the water out. No troubles since then in 15 years...

Or use a sealed relay, unlike me.

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