The 'E' Type Forum

Hi all, I have been a little concerned about running temperatures on my 1964 3.8 FHC, as on the odd occasion if in traffic the engine seems to be running a bit hot. I don't know if I am just being a bit paranoid but when I stop and feel the cam covers they feel very hot - is this normal?
The temp gauge sits at around 76-78 degrees C in normal driving at a steady 2,500 rpm with the oil pressure showing 45psi, rising to 85 degrees and 40psi in traffic. I have a mechanical oil gauge fitted as well as a new temp sender (see image below).
I took a temp reading on both cam covers and manifold and they were 46.3 on the inlet side cam cover, 57.2 on the exhaust side cam cover and 195.7 on the exhaust manifold. (all degree C. see images below)


Guages at 2,500 rpm


Manifold - 195.7 Degrees C


Exhaust side cam cover - 57.2 Degrees C


Inlet side cam cover - 46.3 Degrees C

These readings were taken after a 40 min drive at a steady 55-60 mph on a warm day and a couple of minutes after turning off the engine. Do these figures look normal to you?
Many thanks in advance Jon.

Looks perfectly normal to me

That type of infra-red temperature gun generally measure the average temperature within a circle whose diameter is dictated by how far the gun is from the surface in question - not just at the point the red dot is.

Given how far away you appear to be from the cam covers I strongly suspect their actual temperature is somewhat higher than your readings but nonetheless as DWW commented, well in the range of perfectly normal.

Agreed. Very normal. After only 25 miles or so at road speeds, oil temp can easily be 100C, and water temp 75-80. After a longer drive at speed, oil temp might be closer to 220F. So yeah, fuel engines get very hot in normal operation. I don't start to worry until the water temp gets to 90 and then doesn't go down when out of traffic.

On those numbers your car runs cooler, on average, than any of mine.

Just to throw my hat in the ring..
I run throttle bodies so have an ecu working the fans, so I’d like to think it’s all very accurate.
My fans come on at 80 degrees a little earlier than an otter switch I believe, that was my choice, 90 was the recommendation.
In traffic they are on and off all the time. But she never overheats.
I just fitted an oil temperature gauge, after advice on here that an oil cooler is not needed on a road going car.
That advice was spot on…
The diode goes straight into the sump so it’s accurate with its reading.
On a motorway the oil does not get above 60 C degrees and I have not seen it over 80 C in traffic yet.
I think your temperatures are spot on

That seems too cold for your oil esp if running say 20/50

Paul bow wrote: ↑

Tue Apr 21, 2026 7:42 am

Just to throw my hat in the ring..
I run throttle bodies so have an ecu working the fans, so I’d like to think it’s all very accurate.
My fans come on at 80 degrees a little earlier than an otter switch I believe, that was my choice, 90 was the recommendation.
In traffic they are on and off all the time. But she never overheats.
I just fitted an oil temperature gauge, after advice on here that an oil cooler is not needed on a road going car.
That advice was spot on…
The diode goes straight into the sump so it’s accurate with its reading.
On a motorway the oil does not get above 60 C degrees and I have not seen it over 80 C in traffic yet.
I think your temperatures are spot on

You are indeed a bit paranoid. You only have a problem if the temperature keeps rising after the fans have already come on.

kind regards
Marek

Swindler… yes 20/50 valvoline VR1. Not seen it above 80 however since fitting the gauge (oil temp) I’ve only covered 250 miles, did a 180 mile round trip to the GRRC members meeting this weekend mostly motorway . No traffic.sat at 60/70 max.
I believe 85/95 c is ideal temp.