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The TOP on the stat is to tell the unwary owner that in a vertical fixing position that is the uppermost side! ie to prevent upside down installation.
Greg
Sidescrollin, I had an overheating problem but I think it could be from a number of things. Never been flushed, possibly bad fan clutch, partially clogged radiator, a hole in one of the hoses, etc. So I'm doing the lot: New fan and clutch, new hoses, new T stats and gaskets (from SNG, as close to a "proper" part as I can get), flushed the radiator, and flushed the motor. Hopefully it will behave properly once I get it back together!
Last but not least to this problem and solutions is to increase the coolant flow to the last cylinders A bank 4-5-6 and B bank 4-5-6 by modifying with installation of the Lutz Cooling System Mod. Stage 1. The T-stats have to be of the correct length, wiggle pins to the top or a bleeder hole drilled and positioned at the top of the casting and Lutz Stage 1 restrictors to force coolant to circulate to the back of the block on both sides. You can install all of the electric fans you want but they will not solve the hotspot problems at the back, yes, pop the hood and let it idle...do not shutdown.....heat soak drops valve seats, usually at #5 or 6. The Radiator must be boiled out and rodded or recored, Properly bled cooling system that hold 22qts of coolant. Follow DDs bleeding procedure and you will be able to watch the temp guage stay just at or slightly below the normal operating line on the guage. The removal of all of the leaves, etc. between the Rad. and AC rad. also works wonders along with enclosing the radiator around the ouside with insulating foam to force all aire entering the intake through and not around the Radiator. The effort is worth the time, and reduces a lot of paranoia. Best, JW
Restrictor plates for Lutz Stge 1 cooling system modification for InjectedV12 engines. Nb* front hole is smallest 3/16ths....back holes are 3/8-7/16
Lutz Cooling System Mod Stage 1 will make a world of difference around town driving and just cruising. Stage 2-3 for street racing and high continuous speeds.......Autobahn storming....I posted photos of the Stage one mod. somewhere here on the forums in another discussion of the T-stats or ??. Best, JW
Sorry guys the photos just showed up on my screen above Gregs reply, yes they do apply only to the front T-stat castings only, easy to change when you are redoing t-stats......remember in CA use 190deg. stats for smog and better mileage, drop down to 180's for more fuel. etc.
Notice alloy plates are go-no-go design, the smallest hole goes to the front hose stub on both sides.
Last edited by Dr Quail; 06-22-2016 at 05:25 PM.
Reason: Incomplete messaging
Thanks for all the tips, everyone. If (when) the car is ever down for an extended period of time, say for a restoration, I'll address these issues more thoroughly with block-off plates and the like.
One more question. Thanks again for posting the Doug's bleeding instructions, Mac:
FWIW, here's the Dwyer version of V12 cooling system bleeding:
There are different opinions on what works for filling and bleeding but most owners follow the same basic procedure. Here's the process I used on my '88 XJS V12 and a few others. It's not difficult, just messy.
Elevate the front of the car about 8" and then elevate the left front another 2-3" beyond that. Set the climate control for max heat so the heater valve opens.
Remove the bleeder plug from the left radiator tank. You'll see an access hole in the radiator upper mounting panel. The plug is some arcane size but you'll find something in your toolbox that fits.
Remove the caps from the expansion/header tank and from the filler pipe at the front of the engine....up there by the A/C compressor.
Add coolant/water to via the filler pipe until it reaches the bottom of the pipe. Start engine, set heater control to max heat. Let it run at idle until it warms up. Peek inside the filler pipe every minute or so and top up as needed.
When the engine gets warm increase the idle to about 1000-1200 rpm (a helper is helpful here...or just wedge a little something in the throttle linkage to hold it slightly open for a high idle.
Let 'er run and run. Give the upper radiator hoses a few squeezes now and again. Keep checking your coolant level in the filler pipe and top off as needed. Eventually you'll see some coolant coming out of the bleeder. That's good. Wait a while longer and (hopefully) you'll see coolant *really* pouring out of the bleeder. (How much? It's one of those "you'll know it when you see it" things..very messy)
When it's *really* pouring out of the bleeder hole, put the plug back in. Wear some gloves so you don't get scalded. If you can't get the plug back in thru all the gushing, shut off the engine and do it....but I like to leave the engine running if I can. Not worth getting burned, though.
Top off the coolant in the filler pipe...I go right to the top but some fill just to the bottom of the neck... add a quart or so to the expansion tank if you suspect it might be low, button everything up, and yer off to the races. If you've overfilled the excess will be pushed into the atmospheric tank mounted inside the fenderwell. If you've *really* overfilled the excess will exit the atmospheric tank and end up on the ground.
Lower the car and clean the driveway :-)
Cheers
DD
Just making sure I'm understanding this correctly: I elevate the right side (passenger side for us LHD Jag owners) about 8 inches, and then elevate the left side (driver side) 10-11 inches, open up the bleeder on the left side of the radiator, and fill via the filler neck in the center by the AC compressor?
Since you're filling by the center filler neck I'm assuming that the object is to get the bleeder elevated up so that it's the tallest point except for the very top of the filler neck, correct?
ALSO, The trans cooler lines drained a little bit out too when I pulled them. Do I need to do anything to these in terms of bleeding? It doesn't look like there's anything to do besides just top off the tranny fluid once I drive it a little bit, right?
Thanks again everyone, looking forward to getting my cat back on the road!
The one tip I'll give you on the bleeding instructions is don't overfill before you start the process. If your coolant level is at the top of the of filler pipe rather the bottom as referred in the instructions, it'll just get sprayed all over the engine. You have to be careful and patient as you do the initial fill and if you let it go beyond the bottom of the fill pipe, you'll just see it come out later and have to clean it up.
Grant is spot on* on the trans lines . Just hook them up. It's unlikely you lost enough to matter, but double check the level just in case.
I've had good luck parking on a upward slope and filling slowly until the level was at the bottom of the crossover pipe filler neck. I would do 2 heat and cool cycles to burp it, and also topping up the side expansion tank inbetween the heat cycles to make sure there was coolant in the tank to get sucked back into the engine as it cooled.
Reminiscent of 25 years ago had two E-types. Overheated constantly. Cleaned cooling system no help. Installed racing engine oil cooler behind the condenser(# 3 for air) Cooling problem disappeared. Those 4 ltr 6cyl pumped 30 gals of oil a minute and had 12 quarts in the sump. Oil was part of the cooling system ...for what it's worth!
Hey, guys. Digging up an older thread here. I had originally filled the car with water to test it out, and ran it that way for a month or so. I drained the water out and refilled with 50/50 purified water/coolant mix along with the proper amount of water wetter last night, and bled the system via Doug's instructions again. I overfilled a little at first and some puked out of the filler neck *doh* but given time, it eventually bled properly with coolant coming out of the bleeder at the top of the radiator.
Just a quick question: How exactly does this system work? I've heard horror stories of people not bleeding properly and air getting trapped in an engine and causing all kinds of havok. I'm a little paranoid now, according to Doug's instructions the water was coming out of the bleeder but maybe not *really* coming out of the bleeder... I'm tempted to jack the car back up and go through another bleeding cycle just to be 100% sure. The coolant is full to the bottom of the filler neck, and the expansion tank is nearly full as well.
Can someone smarter than I am give me the short version about what I might have to be wary of?
Just a quick question: How exactly does this system work?
That's a long story. Others will probably chime before I have time to come back to this
I've heard horror stories of people not bleeding properly and air getting trapped in an engine and causing all kinds of havok.
right, because it isn't just coolant *temperature* to worry about. It's also coolant *flow* to all areas of the engine, including the cylinder heads. IMHO, the flow is more important than the temperature...although temperature cannot be ignored, obviously.
I'm a little paranoid now, according to Doug's instructions the water was coming out of the bleeder but maybe not *really* coming out of the bleeder... I'm tempted to jack the car back up and go through another bleeding cycle just to be 100% sure. The coolant is full to the bottom of the filler neck, and the expansion tank is nearly full as well.
You want a small geyser coming from the bleeder . A steady stream, no spluttering.
I just went thru the bleed process a couple days ago. I was happy when the geyser was about 6" tall and a strong, steady stream. I let it go like that for about 15 seconds (it's longer than it sounds)
You want a small geyser coming from the bleeder . A steady stream, no spluttering.
I just went thru the bleed process a couple days ago. I was happy when the geyser was about 6" tall and a strong, steady stream. I let it go like that for about 15 seconds (it's longer than it sounds)
Cheers
DD
I wish I could thank that post twice. You can't beat owner experience with these matters, so I'll jack it back up and keep going until I've got a nice, big geyser per your instructions.
I wish I could thank that post twice. You can't beat owner experience with these matters, so I'll jack it back up and keep going until I've got a nice, big geyser per your instructions.
Thanks, Doug!
the reason for the vapor pipes
on the top of the radiator and going to each thermostat housing is for while in operation (auto bleeding...)
In my opinion they are a little small and are prone to easily clogging and rust through....
clogging makes local pockets of steam vapor... and rust through... well we know that causes a steam leak that is hard to detect... and we know what problem a leak causes: low coolant level and then higher than wanted temps...
I might be wrong, and those more expert will hopefully chime in, but in a properly working system a product like water wetter might be problematic and wasn't recommended.
My understanding was that it, and products like it, were developed for racing or other extreme conditions, but use in normal conditions might cause problems. Just as you don't want your engine constantly running at temperatures too high, you don't want it always running at temperatures too low. IIRC, the concern was that your thermostats would cycle frequently and fail prematurely, rich running, etc.
06-15-2016, 11:06 AM
. A steady stream, no spluttering. 
You can't beat owner experience with these matters, so I'll jack it back up and keep going until I've got a nice, big geyser per your instructions.
