I've been doing some reading in the manuals. And I'm "assuming" (with some confidence) the X308 climate control system is the same as the X300.

The only way to defeat the road-speed-sensitive fan control feature is to manually select max cooling or max heating with the temp control buttons.

I also discovered the cut-in point for the blowers. The blower fan inhibit feature continues until engine coolant has reached 30ºC (86ºF). So, if cabin heat is called for, the fans will be inoperative until the coolant hits 86ºF.

Cheers
DD

The point is, doing this gives us a nice and warm cabin. Not doing this, gives us a cold ride.

I figured this out yesterday by accident. I just kept hitting the increase temperature button and it worked.

Still not the best thing for any engine, gasser or diesel, to let it sit and idle when cold. Always best practice to get it up to operating temp as quickly as possible, although, with the AJV8, doing so means letting the thing sit and idle

Doug, with regard to the choke thing; I still feel leery about idling the AJ engine due to how fat they like to run when cold. Although injected, they stay in their cold enrichment for a good while. OTOH, my TR6, my MG and my R-Type Bentley all sit and idle "on choke" for a good 10 mins before I set off in any of them. Granted, with each respective choke pulled (R-Type's is automatic), the idle stays high to keep the plugs from fouling and to help things get warm quicker. Not to mention, it churns the gear oil up a bit so it's slightly warmer when I set off which, for ancient synchros (especially in the '53) makes things a bit less grumbly...

@bergxu - the design of the AJ-V8 is low volume/high flow rate for a rapid warm up, don't worry about it too much, just don't shut it off before it up to temp!

There is a quick way of warming up an automatic car which I've often used. I put the autobox in a high gear with the manual override-so as to minimise the stress on the propshaft/final drive-then slowly build up the engine revs to around 1200-1500rpm.

This avoids the idling problems & immediately puts a proper load on the engine. The churning fluid in the torque converter also heats up the transmission fluid too-which them passes through the transmission oil cooler in the radiator, adding yet more heat to the coolant for a quick engine warm-up.

Using this method, I can get the Jag engine warmed up to full heat on a cold day in less than 5 minutes

Agreed on the first point and can't really disagree on the second point.


IMHO the fat running has to be fairly severe to risk cylinder wash down. I can envision this happening much more easily by walking away from a set choke on a carbureted engine than walking away from a fuel injected engine which will gradually reduce enrichment with no human action needed.

My degree of "leery" is just a bit less than yours, that's all :-).

Personally I'm a just-drop-it-in-gear-and-go driver most of the time. If the weather is freezing or the car hasn't been run in a few days I might wait a couple minutes to let the oil circulate but that's about it. The only time I go back in for more coffee is if it snowed the night before and/or the glass is totally iced over :-)

Cheers
DD

Let me make sure I have this right.

You hold the transmission against the brakes for 5 minutes at 1500 rpm?



Cheers
DD

Roughly speaking, yes. I use 1500rpm for the first minute or so to get the stone coldness off the powertrain, then drop down to around 1200rpm for the remaining time.

I choose a high gear (2nd or 3rd), apply the handbrake fully, hold the car on the footbrake & then gradually raise the engine speed to those figures above.

I avoid revving to the torque converter 'stall speed' of around 2000rpm as that is too heavy-handed & excessive-and puts a greater strain on the powertrain.

I once tuned the engine of an old BMW Diesel automatic car by modifying the electronics to increase the fuelling, and then using this method with full throttle to see how fast the engine could drive the Torque Converter impeller with the car held stationary on the brakes.

Now that was brutal, but I only did it for 10 second periods with a long pause in between to let the powertrain cool down.

It was a very crude form of Dyno test, as initially the 'stall speed' sat at around an indicated 2500rpm-then after maximum fuel enrichment to the point of black smoke from the exhaust, then stall speed had risen to 3000rpm indicated.

I've no idea how accurate the car rev-counter was, as most bog-standard Torque Converters on production cars have stall speeds around the 2000rpm point-give or take a few hundred rpm.

The gearbox was fine after that 'torture test' as I put another 60,000 miles on the old BMW Diesel & the mileage is now at 176k & the gearbox still intact and working fine.

Oh yes, and the 'testing' was done using old cooking old as a 'Diesel' fuel, so the driveway & part of the street smelled like a chip-shop/burger stall after the 'engine tuning'