Cooling flap system on a '74 2.0 stuck open Options

[Lockwodo]

Hi all. As I work through the maintenance issues on the '74 2.0 I bought recently, I noticed that the cooling flaps are wide open (as they would be when engine is warmed up) all the time. Since this is the default position when a thermostat fails, I'll be checking the thermostat and wire/pulley mechanism. But just wondering what priority resolving this should have? It's not like I don't have plenty of other things to take care of (IMG:style_emoticons/default/smile.gif)

The car starts from cold, idles and runs well. I live in an area where it's unlikely I'll be starting and driving the car in temperatures below 60 degrees F. What do you think?

[Superhawk996]

With respect to the temperature gauge, here are the graphics for rough calibration points depending on which oil temperature sender your using (i.e. in the taco plate).



039919268 is the OEM sender (200 C) for 914's. Many have had the wrong (120C or 150C) senders installed over the years which is why the graphic contains the gauge calibrations for those as well.

Normal oil temps for an air cooled engine are much hotter than water pumpers. Oil sump temps in range of 240 - 280 F are not outside the norm for air cooled motorcycles and air cooled T4 engines. You can see this was reflected on the OEM gauge calibration which doesn't start the red zone until 300F.

[Lockwodo]

With respect to the temperature gauge, here are the graphics for rough calibration points depending on which oil temperature sender your using (i.e. in the taco plate).



039919268 is the OEM sender (200 C) for 914's. Many have had the wrong (120C or 150C) senders installed over the years which is why the graphic contains the gauge calibrations for those as well.

Normal oil temps for an air cooled engine are much hotter than water pumpers. Oil sump temps in range of 240 - 280 F are not outside the norm for air cooled motorcycles and air cooled T4 engines. You can see this was reflected on the OEM gauge calibration which doesn't start the red zone until 300F.

The photo below is the temp gauge on my '74 2.0, engine fully warmed up and thermostat and flap system operating properly. Engine is off. Looking at Figure 1 above, my gauge looks the most like the two gauges on the left side of the diagram. My question is, does it look like the gauge needle is registering accurately somewhere in the 210 to 250 degrees F range? I haven't looked at the sender yet to see if it is correct for the '74, but it does at least appear to be working.

[Superhawk996]

[. . . does it look like the gauge needle is registering accurately somewhere in the 210 to 250 degrees F range?

To answer the question straightaway - Looks good. I'd guess closer to 210 but that's fine.

I've never seen the calibration diagrams for the combo gauge but like you, I'd assume it is closer to the early calibration (top left - figure 1). Someday I'll do that calibration but right now I'm in the midst of a house sale so it won't happen soon. All my gauges are packed somewhere. . . . (IMG:style_emoticons/default/headbang.gif)

Don't sweat the details. The bottom line of the gauge like most is to give trend data. It doesn't really matter if your oil is 214.5 degrees or 247. What matters is that you now where normal is and if you see a fast rise toward and/or into the red band, something is wrong.

Just remember, oil sump temperature LAGS cylinder head temperature pretty substantially. So, don't expect that gauge to move around quickly. It is what it is . . . a general indication of overall engine temperature.

[Lockwodo]

[. . . does it look like the gauge needle is registering accurately somewhere in the 210 to 250 degrees F range?

To answer the question straightaway - Looks good. I'd guess closer to 210 but that's fine.

I've never seen the calibration diagrams for the combo gauge but like you, I'd assume it is closer to the early calibration (top left - figure 1). Someday I'll do that calibration but right now I'm in the midst of a house sale so it won't happen soon. All my gauges are packed somewhere. . . . (IMG:style_emoticons/default/headbang.gif)

Don't sweat the details. The bottom line of the gauge like most is to give trend data. It doesn't really matter if your oil is 214.5 degrees or 247. What matters is that you now where normal is and if you see a fast rise toward and/or into the red band, something is wrong.

Just remember, oil sump temperature LAGS cylinder head temperature pretty substantially. So, don't expect that gauge to move around quickly. It is what it is . . . a general indication of overall engine temperature.

Awesome (IMG:style_emoticons/default/agree.gif) thanks Superhawk996, one less thing to fix (IMG:style_emoticons/default/beerchug.gif)