We had some heated debates over the Holidays regarding what constitutes overheating in our region of the world (Southern California), so I thought I would post the question to all of you Jaguar experts.

I prefer 70 celsius and begin to stress when our 4.2 liter edges above 90 celsius.

Please reply with your thoughts.............

Regards to All............

 

If it is not running near the halfway on the gauge, not normal. If running higher than the normal and near the 3/4 too hot! Better be checking system and fans.

 

Jagfixer, thanks for the feedback........ The '66 has celsius temps listed in the gauge. I'm interested in running temps, where possible.

Regards,

 

Leopard:

30c = 80 F, 40c = 104 F, 60c = 140F, 70c= 158 F, 80c= 176F, 90c= 194F, 100c= 212

165F = 73.8c, 175F = 79.4c, 185F= 85c, 195F= 90.5c

I believe thermostats are available from 165 thru 185 for the 4.2L.

The running temp for a 165 would be 74C , 175 would be 80c, and 185 would be 85c.

So normal running temp varies to what thermostat you have in the Jag. I ran 165 during hot summers and a 185 in the winter.

Your 70c is a cold and rich running engine. So in warm weather the temp should be minimum 74c or 80c or 85c. I would prefer to be between 80 and 85 any higher you will not have an area of shut down in case of temp rising which is 15c or 27F from boil over.

Now what antifreeze you use will increase the temp of boil over by up to 18F.

As long as the system has been drained and flushed and refilled, and rehosed every 3-4 years holding and 80c-85c should not be a problem. I only had problems with corroded core plugs. Rusted from outside.

 

Jagfixer:

Great detail, this is the info I was looking for .

The positive takeaway is that we are running in the mid-range of ideal, so I'll declare victory.

Thanks again and hope to meet you someday,

Geoff