Testing Thermostat Functionality

[dang]

Insufficient cooling at low speeds or when stopped (but adequate cooling when moving) suggests not enough air moving through the radiator because the fan clutch, fan itself or drive belt is not/no longer in the game. It is less likely to be a partially blocked radiator.

I'm with this thinking also. If you're driving around and it's fine then the thermostat is already open. Not sure how it could stick closed or partially closed at this point, unless it never opened fully from the start. If you reduce air flow, like sitting in traffic, it points to air flow components or a system that's not working very efficiently and only needs a little extra heat to cause problems, radiator partially clogged etc.

My E3 is doing the same thing so I'm replacing the suspect radiator and adding a pusher fan.

 

[Dick Steinkamp]

For extra credit: Is there a generic temperature sensor that will fit into the existing, threaded fitting on the lower radiator port? I am running a later radiator that I sourced from Mesa Performance. My idea is wiring this sensor into the fan relay to switch on the pusher when the A/C is off and coolant temperature high. And yes, a diode would be needed to ensure that it doesn't switch on the compressor fan clutch as well.

It doesn't sound like it is overheating with the AC off. You probably should try the driveway idle test both ways (AC on and AC off) to pin down the problem (if there still is one)

You can wire the condenser fan (either existing or new) with a relay that is looking for a ground from EITHER the pressure switch on the compressor OR the engine temp sensor to close the relay and turn on the fan. If it sees both, that's no problem.

One cause of the engine heating up at idle on these cars is their use of retarding the spark at idle to reduce emissions at idle. A bad side effect of doing this is a less efficient and hotter engine at idle. Easily fixed by using the manifold vacuum line on the advance side of the dizzy instead of the retard side and removing and plugging the ported vacuum lines that were on the advance side of the dizzy. You'll have to reduce the idle speed when you do this. It will noticeably increase since the engine likes a lot of advance at idle to burn that lean mixture and it will be more efficient and run cooler at idle.

 

[Stevehose]

I live in temps of 95 degrees with very high humidity. If you have a properly setup viscous fan clutch, 9 blade fan, proper radiator/thermostat/water pump, your stock engine shouldn't overheat, mine is steady 185 no matter the ambient temp. I prefer not to have pusher fans beacuse it seems like a band aid to an ill-functioing system, plus they are very loud, my friend's is louder than the engine. My $.02

 

[HB Chris]

The fan can’t be squeezed in without removing radiator and then pulling condenser inwards. Mesa can get you the sensor to go with your diode.

 

[HB Chris]

I live in temps of 95 degrees with very high humidity. If you have a properly setup viscous fan clutch, 9 blade fan, proper radiator/thermostat/water pump, your stock engine shouldn't overheat, mine is steady 185 no matter the ambient temp. I prefer not to have pusher fans beacuse it seems like a band aid to an ill-functioing system, plus they are very loud, my friend's is louder than the engine. My $.02

My Spal fan has straight blades and is louder than a jet turbine.

 

[jmackro]

One cause of the engine heating up at idle on these cars is their use of retarding the spark at idle to reduce emissions at idle. A bad side effect of doing this is a less efficient and hotter engine at idle. Easily fixed by using the manifold vacuum line on the advance side of the dizzy instead of the retard side and removing and plugging the ported vacuum lines that were on the advance side of the dizzy. You'll have to reduce the idle speed when you do this. It will noticeably increase since the engine likes a lot of advance at idle to burn that lean mixture and it will be more efficient and run cooler at idle.

Hmm - perhaps this modification has already been made. I see that the port to the upper vacuum chamber has been blocked (1st photo below). There is a vacuum line going to the bottom chamber (2nd photo) and that line comes from the base of the forward carburetor (3rd photo). So has that "retarding the spark at idle to reduce emissions at idle" already been eliminated?

 

[Dick Steinkamp]

Hmm - perhaps this modification has already been made.

Sort of. The vacuum retard has been disconnected, but the advance side of the dizzy is hooked up to ported vacuum. That means the dizzy does not see a vacuum signal until the throttle plates open and uncover the ported vacuum port. So at idle, the engine is not receiving additional advance.

It is certainly a step in the right direction. At least the ignition timing is not being retarded at idle like it is stock. Most owners leave things like this and that's OK. But for best idle performance and the least heat induced by timing at idle, I hook up that side of the dizzy to manifold vacuum...the port(s) where the retard side of the dizzy was getting the vacuum signal. Again, the idle speed will increase when you do this since the engine is happiest with lots of advance at idle. You'll have to set the idle speed back down to spec with the idle speed screws on the carbs.

 

[jmackro]

the correct thermostat for your car is an 80* C thermostat. It should open at 80*C.

The OEM fan is a joke. Throw it away. Install a PUSHER fan with minimum of 1500 cfm with curved blades.

Just to provide an update on my (slow) progress:

As Don had advised, I have an 80 degree C thermostat and a Spal 14" curved blade e-fan on order. Will create a thread describing how I mount the fan.

While I am intrigued by Dick Steinkamp's suggestion to pull the distributor's advance vacuum signal from the manifold, rather than the carburetor, I am holding off on that one.

 

[shanon]

'Anybody running an Aux/electric Fan?' https://e9coupe.com/forum/threads/anybody-running-an-aux-electric-fan.1420/post-10680

"Operation: Arctic Wind"

Been working great for 15years at over 100deg CA summers...

Hth!

 

[Arde]

'Anybody running an Aux/electric Fan?

"Operation: Arctic Wind"

Been working great for 15years at over 100deg CA summers...

Yep, and manually switched by Shanon I recall.

Reminds me of the joke about the guy that flunked his high school test:

A - At what temperature does water boil?
B - At 90 degrees.
A - Wrong, it boils at 100 degrees C.
B - Ah, yes, the right angle boils at 90 degrees.

 

[mulberryworks]

Yep, and manually switched by Shanon I recall.

Reminds me of the joke about the guy that flunked his high school test:

A - At what temperature does water boil?
B - At 90 degrees.
A - Wrong, it boils at 100 degrees C.
B - Ah, yes, the right angle boils at 90 degrees.

Yes, but if he was at 10,000 feet, water does boil at 90°C.