328 Oil running hot with gauge going up and down....help!!

Check your fluid levels. Also the dipstick method can vary from what I’ve seen posted….. FWIW when I change my oil I check the dipstick then what is actually in the drain bucket and filter. Yes can be different…. Just saying….

 

A little smoke might be ok because the cam seals weep a little. Mine were upgraded to silicon seals but still weep a little. No drips just a little weeping. So, on a nice drive where the engine gets good and hot, there is a bit of smoke. Not nearly as much as when the seals leaked more with rubber O-rings.

 

The question of oil temp mid to max fluxing is concerning. I’ve never had max unless it’s run very hard…. Just saying….

 

Don't like your smoke-smelling symptoms (so that may need other attention), but the oil temp gauge swinging so much in such a short time, and in both directions, feels more electrical. (not easy for a big volume of oil to heat up that quickly, and, if it really did, it wouldn't cool off quickly). First thing I'd do is inspect the wiring going to the oil temp thermister -- chaffing/shorting to a metal ground can cause such a gauge movement (as grounding the wire = sends gauge to maximum).

 

Oil burning off from a leak would not be non smelling, gear oil even more so. Maybe some coolant weeping from one of the hoses, or perhaps the clutch slave/hose against that firewall area is leaking some brake fluid. Not sure what cooking brake fluid smells like.

 

Not sure 328's ever had a hydraulic clutch?

 

Oil or water from a leak will usually find its way onto your garage floor, especially if you put the car away warm after a run.
This should give you a clue!

 

Check the coolant level ( of course when it's cold ) 10 minutes is short run and if all others thing is ok ...

What about service history ? Any pictures ?

 

Absolutely agree with this, even if my knowledge of automobile electrical matters is infinitesimally less than Steve's. But some good common sense here.
Should you be stuck in city traffic with the car, and the oil temperature goes up to about 100° centigrades, you need about 10 miles of normal, un-impaired driving and free flowing air at say 55 mph (our equivalent would be 90km/h) for the oil needle to go slowly back to "normal" temp (= 75° centigrades).
I do experience this very often; last time was on this very Tuesday.
The temperature of 8 litres of engine oil cannot jump from 75° to 100°, or back from 100° to 75° in a matter of seconds.
That must be some electrical connection to the temp gauge.

Rgds

 

No, it does not; the "Mondial" has one, but on the 328 the clutch is cable-actuated.
By The Way, if my memory serves me well, suggesting that the 328 has an hydraulic clutch is one of the few errors in Keith Bluemel's book.

Rgds

 

Does it smell like coolant? There are rubber hoses/connections in the valley between the heads. There also is a little thin-walled small coolant nipple that will eventually corrode away. It is attached to the small hose that goes to the coolant reservoir. The hissing you mentioned prompts my comment. You may have two issues, one definitely being electrical as previously mentioned. The other might be a coolant leak.

 

If you do a search on the "107576" part number of the oil temp thermister, you'll get some prior threads -- like this:

https://www.ferrarichat.com/forum/threads/oil-temp-sensor.587540

I can't recall if the exact resistance vs temperature behavior for 107576 has been posted, but I would be surprised if it was radically different than the water temp thermister 104628 (and I know the resistance vs temp for that one has been posted).

 

That (4.6 Ohms) seems a crazy low resistance, but if you mean that it was 4.6K Ohms = that's a high resistance for these thermisters. Usually the resistance of these thermisters are in the hundred to hundreds of Ohms ballpark. Please clarify.

Certainly wouldn't hurt to make a resistance measurement of the sender both when cold and with warm engine to compare the values.

One simple test to do here is:

1. disconnect the wire from the sender with the disconnected wire not touching anything = the gauge should read minimum when the key is "on", then
2. touch the disconnected wire to the engine block (with key "on") = the gauge should go to maximum.

 

Yes, that the engine oil temp sensor in the forward-facing side of the wet sump near the bottom -- item 34 here:

https://www.ferrariparts.co.uk/diagram/ferrari/328-gtb-gts-(1985)/020-lubrication-system

 

Well, that's pretty bizarro! The water temp thermister is item 35 here:

https://www.ferrariparts.co.uk/diagram/ferrari/328-gtb-gts-(1985)/022-water-pump-and-piping

You could try the same test on that wire and see what happens. I don't think they "share" anything. Maybe the two gauges are close enough to each other that someone had the dash apart and got the wires swapped -- just a thought. Or maybe they swapped the gauge positions, yet kept the same sensor wire attached -- have you confirmed that your water temp gauge and oil temp gauge are in the stock locations specified in your 328 OM?

 

Please plier tighten the female connector lightly so the connection made is firm not loose

 

They dont, they are cable operated, I replaced mine a while back.

G

 

I wouldn't guess "thermostat" with your report of the indicated water temperature going up and down so quickly -- so would still more suspect the wiring going to the water thermister or the water thermister itself (but doing the "ground the wire" and "not ground the wire" tests on the wire going to the water thermister could give you some confidence it is not the gauge if the gauge correctly, and always, moves from min to max for each test). I know people have posted what the resistance vs temp for the 104628 water thermister should be (it's used on many F models). I'd add that Lawrence had a good point that you may just have some sort of coolant leak from a old/bad hose or a corroded fitting letting out some steam/liquid -- especially if you are now using a 328 that was a bit unused/neglected for a while.

 

It could. of course be an electrical issue with the sensor/gauge. Low coolant level can also do that; I hope it is one of those two. But my first reaction upon seeing your later post that it was water temp, not oil temp that was showing the variation was: possible blown head gasket.

A blown head gasket can exhibit the water temp variations you are describing as well as the hissing which indicates pressure that is escaping from the cooling system after the engine has shut down. The smoke you mentioned (possibly coolant in the exhaust) is also be a blown HG symptom.

Check the coolant level before going out for a run, then check it after the run when the engine has cooled. Along with the symptoms you described, If the coolant level drops from when the engine is cool before a run to low when the engine is cool after a run, I'd go from saying, "a blown head gasket is a possibility" to saying "it has a blown head gasket."