Daimler V8 is overheating

My Daimler is overheating can anyone tell me what the ordinary running temperature for the car

I should have asked any tips for what I should do/check

Hello Michael - welcome to the forum :grinning:

How do you know it’s overheating? Is it the reading on the gauge, or is the radiator overflow venting steam?

Are you losing coolant? If you’re losing coolant then my first step would be to check for leaks - soft hoses and leaks at all the joints, including the core plugs - especially the one at the back of the engine which you can’t see!!

Then I would check the thermostat and either test it in a pan of hot water with a thermometer (the opening temperature is usually stamped on it) or just run the car without it for a few miles to see if it makes any difference.

The recommended rating of the thermostat will vary depending on where you live but if it has been ok before I would suggest replacing the thermostat (if it’s faulty) with one of the same rating.

If you have no steam and you’re not losing coolant then it will be the gauge or the sender giving a false high reading.

Thank you for the feedback. I took the car for it’s first maiden voyage. I must admit I didn’t loose any water, no leaks but the temp gauge was reading almost 110 degrees. I felt that was a little high.

Bob I suspect it might be the gauge. There was no lose of fluid or steam. But I felt it was way to hot. I will check the thermostat. FYI I’m based in Australia

I meant it varies with your height above sea level :joy: :joy: :joy:

Was in Australia this time last year (28 Feb was the day we left). In Sydney for the last 5 days or so. Great holiday. :grinning:

Has the heads been off recently?
That engine has a nasty problem with corrosion in the water ways in the heads. That could be a cause If it has not had the heads off in a long time. I pulled the heads off the V-8 250 I had years ago and found that to be true first hand.
Nice car by the way. I miss the one I had.

Hi Michael,

I would use an infrared thermometer to start off with - and check temps at top and bottom of radiator.

Only if you find it is overheating will we begin to scare you with the possibilities!


To that end the spare parts place in Christchurch were in the process of casting new cylinder heads for the V8, not sure how far down the track they have got.

This is what I did with a recent purchase Morgan Plus 8). Car was indicating plus 100 degrees. I/R thermometer radiator outlet showing 70 degrees. No hissing, gurgling or loss of coolant. The voltage regulator has “top” in it for a reason - turned it 180 on the firewall and car indicted 75 degrees in normal running. You can get an I/R thermometer for about 35 bucks online. Paul.

One more thought. Has it just commenced recently? Might be a failed thermostat if it presented quickly. Paul.

Thank you everyone for you advise. I have plenty of tips to go on. Will advice once I have found the problem. You all have been most helpful and I appreciate it

I would also suggest the problem may be the instrument voltage stabilizer, located behind the center dash panel. As for the engine ‘feeling’ hot after a drive, even at 70 degrees C after a drive, the engine would be more than hot enough to burn of several layers of skin if one dared to touch it.

Another area to double-check after you verify the possible coolant and instrument issues is fuel mixture and distributor advance. A lean mixture and incorrect advance can make the engine run hot.

I used to think the 70 mark in the middle was correct running temp. I run almost at the 100 mark without any problems on a cleaned out stock radiator. I also use USA style thermostats with a bypass plug in the small hose to slow the flow. I might be able to dig up a picture of the plug.


Thanks Gerard. A picture if you don’t mind would be handy.



Very old video here. I could measure the diameter if need be as I never did install it:


It might be a failing thermostat. You would be wise to invest in
a FAIL SAFE thermostat, among other things.