THE INTERNATIONAL JAGUAR 'S'-TYPE REGISTER FORUM

Up to now even on one of so called hottest days 32C in the U.K. mine ran at 70 on the temp gauge.
Dave J.

+1^ with the Aluminium radiator. I would go back to a copper radiator with an uprated core. Orlando's thermostat advice is crucial to get all the coolant going through the radiator warmed up & as little as possible via the bypass slot.

Modern chemistry additised fuels produce soft combustion chamber carbon deposits that will blow off with spirited driving. Why we no longer decoke engines.

The engine should have the smallest fuel supply possible to discourage run on ~ hence low idle speed being important.

Cody's car has the rather good Artic Kar aircon fitted that was done by many US dealers. Trouble is the condenser unit fouls up the airflow to the radiator a little so it needs all the cooling help it can get.

Mine also runs at 70-75C, but I expect in LA it would be at 80C.

90C does seem a bit high, if the gauge/sender is to be believed.

I'm not a huge fan of alloy radiators. If I were you, I'd go and get the old one back from the dealers and have it re-cored. They will have fitted an alloy one because it's cheaper.

Once you've satisfied yourself over the gauge, you'll need to get to the bottom of that running on. As Glyn says, these engines do collect carbon on top of the pistons, which is unhelpful and does encourage it.

How do the plugs look? If the engine is running too lean, it will run hotter and that may encourage running on.

And did you check that you have a sleeved 74C thermostat?

I'm sure we can help you get it running nicely. :)

My car runs at 70 degrees C all day long. Check the accuracy of the gauge with a contact thermometer at the sender unit. Please note that octane rating displayed on USA pumps is AKI or Anti Knock Index. Most countries display Research Octane Number so US fuel is of higher octane than it might appear. (i.e. AKI = average of RON & MON ~ Research Octane Number & Motor Octane Number). Most fuel in California has some alcohol/ethanol in it. Euro 5 & 6 style fuels are not available in the US. They want it cheap so refineries will not upgrade.

You could be suffering some incandescent carbon in the combustion chambers if correctly tuned. Run Techron concentrate in a few tanks of fuel & take the thing out on the highway & give it a good Italian tune up i.e. thrashing to blow out the crap.

My car correctly tuned on 95RON gas in a newly rebuilt engine will suffer a little run on if it does not settle to a correct low idle. I had a slightly sticky throttle linkage & the car would idle a little high & run on at shut down. This remedied it now idles at approx 600rpm & no run on. These cars would benefit from an electronic fuel shut off valve a la old VW's but there is no provision in SU Carbs.

Back from holiday and catching up with the forum. Welcome to the forum Cody, a great looking car you've have bought. Rob just posted everything I was going to say so wont repeat. Rob mentioned the fuel quality as I found when I ran both my XJ and my S Type cars in the US I had a lot of problem with running on and ended up with bent valves in the S Type so try to find the highest octane fuel you can and the lowest ethanol content possible.

BTW mentioned earlier I also have the original bonnet insulation on my car.

Cody, Cheap fuel of only 95 Octane can make the car run on. I try to use only 97 octane in mine as I had the same problem. Changing the fuel, tuning the carburettors to weaken the mixture and adjusting the timing slightly should help.

With the the temp of the engine mine runs below 70 degrees all day long but I do live in a cooler climate in the UK and the engine has been completely rebuilt. The temperature of the engine is controlled not just by the water in the radiator but mostly by the temperature of the oil. If you have flushed the water system out I would suggest you also have the engine flushed as well. This will do a couple of things. One it will clean the inside of the engine from all the dirt and grime a combustion engine produces but it will also clean all the oil ways so the oil can lubricate the engine better but with the better flow of oil it should cool the engine better. Living in a hot climate such as LA it might also be advisable to fit an oil cooler to the engine. Always better safe than sorry as these engines are a 70 year old design and it has been running for over 50 years in your car. Constant maintenance keeps the big bills away.
Attached is a photo of my gauge but as a word of warning do not take the gauge as gospel as they are not necessarily that accurate and are just an indicator. Mine could be way out on the cool side and yours could be way out on the high side. As long as the temperature showing is constant that is a good thing. If it rises above what you would consider to be normal then start worrying. Having the gauge calibrated might be a good idea.

Hello Again Everyone!
So I got my new 3.8 S back from the mechanic (it also needed a rear brake rebuild, glad that's done!). They flushed the cooling system and found no issues, but they did replace the radiator with an alloy unit and larger cooling fan.
Drove the car today for an hour and everything seems to be okay. Attached is a picture of the temperature when I shut down (it was right around the same mark driving).
But I have a new problem, the engine diesels when I shut it down after a long drive...I'll have a look at the timing now :lol:

There are a couple of threads in the archives that cover heating problems and how we created an expansion tank from a washer bag that fits under the front wing out of sight which someone nicknamed the Bladder Bag.

http://www.jagstyperegister.com/forum/viewtopic.php?f=18&t=51&hilit=bladder+bag&start=10
http://www.jagstyperegister.com/forum/viewtopic.php?f=13&t=347&hilit=bladder+bag

If you have an overheating problem than I would suggest a good flush of the coolant system including the heater matrix which is cut off from a cold engine so should be flushed separately. The Jaguar engine never had an overheating problem when it was new but we all know that if the car has been sat around for some time any sediment in the coolant will sink to the bottom of the radiator and possibly block or at least restrict the flow of coolant around the engine. As Glyn has said a recore of the radiator is not that expensive compared to an engine rebuild and radiators do not last forever. I have just had my radiator recored again but for a different reason, (see my disaster post) and it cost £400 plus tax. A new radiator from SNG was over £1000. You can buy an aluminium radiator to fit the S Type from China for as little as £150 but you take your life in your own hands fitting it and forever wondering if it is actually going to keep your engine cool. Besides the aluminium radiators look horrible and if you do see one under the bonnet of an S Type or Mk2 Jaguar you will always think that the owner is tight with his money and does not care about his car. Originality was beaten by cost!.

When you do flush your engine you will be surprised how long it takes before the water once again starts to run clear rather than rusty brown.lol.

Thanks for posting those pix, Glyn. As you say, it does look pretty much like a standard radiator.

I'm not sure these help at all Orlando. P/N C27105U & manufactured by Nigel's pals at Northampton Radiators for Barratts.

Mine:

[attachment=2]IMG_20180308_180358.jpg[/attachment]


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Re-cored original:

[attachment=0]Painted-and-Recored-Original-Radiator-950x713.jpg[/attachment]