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Over the many years I've noticed that fewer complaints of overheating come from XJ12 owners compared to XJS owners. One might easily conclude that, since there were far fewer XJ12s made, it makes perfect sense that the complaints are fewer and farther between.
But.....
I've oft wondered if the different grille arrangement comes into play.
Looking down the B bank side on the Series cars, the top of the oil filter was visible, not so on the XJS. Never went any further with the thought, but, maybe the Series cars do have a slightly more roomy (play on words there) engine bay than the XJS?
Also, the rear of the engine was easier to get at than the XJS, but only just.
Last edited by Grant Francis; Sep 10, 2020 at 03:04 AM.
Reason: Spelling still sucks.
I am taking apart an '88 H&E convertible. Selling most things but keeping a few things for myself. Specifically the engine and trans; the Delenair III; and a couple smaller odds and ends.
The hood is off and I got to thinking about keeping it as a spare. Then I got to thinking about the possibility of having hood vents added to it ala XKE style. These motors get wickedly hot it seems. Giving that heat somewhere to go just makes intuitive sense. Has anyone else done this? What is involved? About how much would it cost? They would obviously have to be somewhere that the drip rails needed for rainy conditions did not interfere with the intake manifolds.
I think these cars would look great with hood vents. JMO.
An alternative solution is the following: The heat is coming from the engine more specific from the exhaust manifold who disperse the heat into the engine bay. It takes some labor but take off the exhaust manifold and let it ceramic powder coated. You can even choose the color. The coating keeps up to 70% of the heat inside the exhaust manifold reducing drastically the heat in the engine bay back to normal temperature. It's a one time thing to do and solves the problem. I'm a race official and I see this application on race cars all the time.
No surprise that the big brother states (northeast and west coast) require them. I'm surprised by Texas though. I lived in Ohio until the mid-90s, and they required them then. Glad to see they woke up. When I lived there, I had to remove the front plate on track days because it made a big difference on the Porsche 944T I was driving at the time.
I have had a couple cars, my XK and now my XE that didn't have front plates for years but it was never enforced. I also see a ton of exotic and luxury sports cars without front plates.
I stripped this car down to bare metal in the early 1990s to get rid of the original brown paintwork.
At the same time had a set of louvres punched into the bonnet.
Made a clear polycarbonate cover to go over the V and keep the ignition area dry.
After all was ready again fitted 5 or 6 temperature sensors around the engine bay for monitoring. Greg is correct, no great difference to cooling when driving. It does make a significant difference to cool down the engine bay after driving. One of the hottest place is on top of the radiator, so do not put anything there that is heat sensitive. The only really cool place is in front of the radiator.
pic of my thermal ceramic coated exhaust manifolds , dont know if it helps much never ran the car before/after results!
but never in 25 yrs have i had an overheat, engine mounted Digital read out gage never seen over 200F(once)! NO boiling tho! ceramic coated ceramic coated
average temp runs 185F all the time rises to 190F after 10 minutes shut down!
central TEXAS can easily go to 100F + in late afternoons!
