Just finished the restoration of my XK120 and drove it for 200 miles, everything is working great, but I want to get your experiences on the cooling system. The coolant temperature is 78-82 degrees while the car is moving. When I stop in downtown areas on several consecutive traffics lights, temperature goes up to 90-92 degrees, no overheating. As soon as I get moving again, within a minute, it goes back to 80. My conclusion, the stock fan does not move enough air when stopped, which I understand is known about these cars. I live in Seattle area and temperatures right now are 60s to 70s, so not very hot. First question: is this normal for this car and is the car at risk of overheating as Ambient temperatures go up to the 80s
I see a lot of cars with electric push fans, but I don’t like the look, so I came across a plastic fan that is advertised to move more air, anybody have experience with such fans?
I see no side vent doors so this is an early car and I presume you have the 5 blade fan and your block, head and rad were well cleaned. Your temps sound ok for Seattle. I’m in Chicagoland with similar temps and have the 6 blade fan which is a little better. I had an electric auxiliary fan in front of the radiator for many years but found I never needed it so I took it out.
Your car’s behavior thus far is normal but I can guarantee a “new normal” where after driving at freeway speeds, on a hot day, when you must then slow down in traffic, you will see much higher temperatures and wish you had some cooling help.
The problem with the stock 6-bladed fan, or even engine mounted fans with more blades, is the lack of a fan shroud to encourage the fan to pull air through the radiator and not just mix up the air in the front part of the engine compartment. Though not attractive, electric fans, attached at the front of the radiator, are quite effective and some need only be installed temporarily during the summer months.
My car is a 1950 but the engine has the later six blade fan. Seems everything is normal and 90 degrees is not high. My other car is a 63 E Type and it’s never gone over 80, thus my concern
The XK140 and 150 both had shrouds but, because of the very limited 120 work/mounting area, I personally have been happy with using one(s) ~ 10” diam. (in front of the radiator) that look good (black) and are routinely available at local commercial parts stores. (Thermostatic switch not really necessary.)
Because I was showing my cars regularly and wanted to be able to remove the fan easily, I initially avoided any extra wiring and switches by simply using the extra positive and negative terminals in the 10-way connector, on the left side of the fairing in front of the radiator. I connected the fan such that I could turn it on simply by turning on the side/parking lights. A separate switch really isn’t very hard to do, either. It was very easy to hang the fan from the horizontal wing-brace in front of the radiator, with rubber padding to protect the cooling core/fins…
(I have a nice extra electric fan I used briefly on an E-type. If you want to give it a try, I can help and probably at the right price.)
This is the fan I’m using on my 120, acquired from Guy Broad. Like you, I’m not keen on the look of an electric fan, plus I’m using the standard generator. So far, my experience is similar to yours, no overheating as such. Make sure you have the small closing panels fitted in the front of the rad at the sides, as they are often missing, and will stop some cooling air being lost around the sides of the radiator. The small horizontal panel in front of the bottom rad tank would also help a little, I guess.
it’d be interestin to know what temp thermostat you have…as its job is to keep the coolant temp near to the thermostat temp… that said…78 to 82 is quite acceptable…as is temps to 90 on occasion. You should have a 4 lb cap. A “trucker” trick…affix a small windshield washer pump, with water container, hidden…say up under the fender…out of the way of course of tire in a turn., run the small hose with spray nozzle tip to the front side of the radiator…so that at 90C.or so you can.use it to spray a mist onto the radiator…this will drop the temp…for a little while…thru traffic or stop lites…until back up to speed. Nick
@Nickolas thank you so much, my first restoration, bought it last July with body and engine restored and the rest in boxes, it’s been challenging and fun, still have the interior to do, but I’ve been driving it, brings smiles like nothing else
I’ve seen a racing 120 in period with some kind of thick foam rubber stuck to the top of the radiator to prevent air getting past over the top of the header tank. That would look very ugly, but if stuck to the underside of the bonnet (hood) it would be much less noticeable… Now I think of it, it could have been a C-Type, but the principle remains the same. Your 120 looks beautiful, BTW!
quite normal temps you are seeing…yes will go up in summer heat when in traffic, slow speeds, Water Wetter or similar product in coolant only helps a few degrees when in anti freeze miz…but …a few degrees is helpful…With anti freeze mix at low elevation your boil point is above the 100C…but still…you don’t want to go there…there is a good club in the Seattle area to connect with other XK etc…seattlejagclub.org (Jaguar Owners and Restorers Club, ) and some good Jag XK shops in area…contact thru the Club…plus it is part of JCNA and Haggerty offers a discount on insurance. Nick
