Sounds like a nightmare.

 

Thats really interesting Bill cos my temperature gauge reads normal but engine bay get stinking hot. Has extra complication of being a 4.2 with trple SUs. Im going to install an electric fan and see if that helps dissipate heat!

 

the fact that the engine bay appears to be abnormally hot, yet the engine temp is reading normal is good. if the gauge is accurate (easily determined with an inexpensive laser temp gun) it would mean to me that the cooling system, especially the thermostat, water pump and radiator, is doing its job. and if so, what are the disadvantages you are having with what appears to be the excessive heat in the engine compartment? for instance, are the rubber parts aging prematurely, is there a problem with vapor lock in the carbs or fuel lines?

regardless, i'm assuming the fan's purpose would be to disperse hot air from inside the engine compartment at idle or at very, very low speeds only. and not provide additional engine cooling inasmuch as you've observed no engine overheating.

i guess, forgive me, that i'm questioning the purpose of an additional fan.

 

I would take a guess and say 60 to 90% of the heat in the engine bay is coming from the exhaust manifolds. Putting a fan on the front of your radiator is a complete waste of time and money in this case. Try heat wrapping the exhaust manifold or getting the exhaust manifolds ceramic coated to reduce the heat. Better long term investment than a useless fan in the front grill pushing cold air through a hot radiator which heats it up adding more heat to the engine bay.

 

I have extensive real world experience with the Jaguar sedans and the heat issues as my car is even more extreme with a 500 HP GM aluminum block LS V8 and you are not correct. Wrapping or coating the exhaust headers helps a bit but that is not a solution. Adding a pushing in front of the radiator and a puller fan behind actually helps more. The real big change that improves the most is to enable the hot air of the engine bay to exit out. I did that by the addition of an ram air scoop under the front of the car to grab airflow and push it thru then it exists via openings on the lower rear inner fender well. I did all of the typical things like shielding every single hose in the engine bay, coating the heaters but the only real big way to solve it is create a strong air flow out of the engine bay. I installed a good high quality radiator and that kept the engine cool but the problem with the Jaguar is that the hot air does not exit out of the engine bay well at all so unless you get that air out things like header coating or wraps do very little.

 

I agree you have extensive knowledge of heat under the bonnet but not Jaguar real world heat. Your 500 BHP V8 is not Jaguar real world. It is possibly producing twice the heat a standard 3.4 / 3.8 is producing (twice as many headers to start with) so what you have done is commendable for your installation but not required for 95% of the real world Jaguar sedans out there.

Do you not find that by forcing all your hot air out of those holes in the sides of the inner wings that your tyres and brakes don't over heat? Do your feet not get extremely hot in the foot wells?

And please tell me you have not added LED strip lights in your wheel arches!

 

The issues I had to deal with yes were more extreme due to the V8 and power but those are not normally needed on other engine swaps or performance upgraded engines in other cars. The Jag does have a unique issue and the OP has a mild case of what I had to deal with. To me even his issue is the same his mildly increased temperatures of air are not getting out of the engine bay. Probably a bone stock Jag will do ok, but I still wonder if any of you drive your Jaguars daily and if you do you would sometimes get stuck in hours of stop and go; does your Jaguar temperatures have any issues?

I have no issues with the brakes, nor feet getting hot Oh but I have added LED strips in the wheel well, under the chassis which are on a manual switch

 

Yugh!

 

Thx. Yep, the idea is to get a bit more air movement to try to remove some of the engine bay heat. I had vapour lock last week on a relatively cool (25 deg C day). Will take the car for a spin next week and see if my hardwork has made any difference!!

 

Did you have Winter grade fuel in the car? We as an oil industry make Summer and Winter grade fuel unless you are in a place like Singapore on the Equator. Winter grade fuel has more light ends in it for easy cold starting. In low use vehicles this can catch you out. If you use Winter grade fuel in Summer you will be more inclined to suffer vapour lock.

 

I do believe that just some type of ram air scoop in the front even without making cuts into the inner fender well will help the airflow somewhat and more than other things. You can paint it black and it will look like an air dam or front valance but having it angled up so the air is scooped to then go around the engine will help force some air out of the Jaguar's oven of an engine bay. As I said that air scoop did the most for all of this heat.....