I have noticed that about every 3-400 miles or so, my "coolant level low"
warning goes off. When I check the coolant level at these times, it has typically fallen by about 10-12oz.

Recently, I found a small puddle (4"dia) of pale rust (dirty orange?) near the front passenger side under the engine about 1-2ft. away from the right front tire. I lack a lift, so not quite sure if this is the problem area or not.

Any ideas on what might be causing this slow loss of coolant?

2003 XKR

Thanks, guys.

Ed.

 

The puddle of "pale rust (dirty orange?)" is almost certainly long life orange coolant.

From the location it's probably overflowing from the Atmospheric Recovery Bottle in the inner wing behind the black wing liner.

JAGUAR XK8 - Expansion Tank & Recovery Bottle.pdf

When the coolant expands at engine operating temperature, the excess goes into the Atmospheric Recovery Bottle. As the engine cools, this is drawn back into the Expansion Tank.

If the top of the Atmospheric Recovery Bottle is loose or the pipes aren't secure, the coolant may be leaking onto the ground accounting for the gradual loss.

Graham

 

Over the past month or so, my low coolant warning light was going off about once every two weeks, requiring about 2 cups of coolant to top it off. I had no puddles or leaks under the car, but could smell the sweet burning smell of sizzling antifreeze. Turned out the flanges (connectors) on the heater core hoses were failing and allowing coolant to drip on hot manifold where it vaporized before hitting the ground. I replaced the heater hoses (requireds dropping the exhaust system), and the leak appears to be gone.

 

When I had my XJ-S I went crazy trying to find an invisible leak. Only found it when I got a radiator pressure tester and discovered a barely visible heater hose had a pinhole that leaked and evaporated instantly. Can't remember now exactly what the coolant was leaking onto, but it was such a small stream that it was near impossible to spot. No steam, no puddles, just a low reservoir.

 

Because it was so far away from the front wheel it could be the atmospheric drain, this means your tank is over full and not draining back, this is caused by a faulty pressure cap.

Good luck

 

+1, almost guaranteed to be the cap.

 

Drinaed my radiator on the 05 Super V8. Refilled with Dex cool and water wetter. Close it up. Ran engine with heater on. No leaks.

Next day started the engine with heater on. Leak. Behind the oil filter but I can't get a clear look at where it migh be from. Shut down check level. OK. Restart with heater off. No leak. drive to store. No leak coming or going. (Checked twice...) Home. No leak. Shut down. Restart with heater on: slower leak. Turn heater off. Leak stops. Level Still fine. No issues previously. Car has 53K. HELP!

 

I had the same symptoms, ended up being a small crack in the seam of the reservoir. Replaced the reservoir and never had a problem since.

 

Will Check the resevoir. I am assuming the resevoir is the Overflow/ fill tank with the big pressure cap where you add the coolant and check the cooloant/ antifreeze level. Right?

 

Yes, but have you looked at the heater hoses and connections to the dispersion valve unit?

Have any of you ever found a pressure tester that fits our coolant tank opening?

 

I haven't tried to locate any pressure testers.....Yet. The car ran fine all the way to Sacramento and back.....(Over 100 Miles.) No loss of coolant. No over heating (Which it has never done anyway...)

P.S. Previously i added a yellow super coolant additive. When the coolant was drained this stuff DID NOT mix with the antifreeze AL ALL. it was yellow blobs. Like oil and water. FYI

 

Ya gotta be careful of some of these new "miracle" additives. Unless they are really proven over time like "Aluma-Seal" or a few others, many of them are garbage.

I monitored my coolant on this trip -- just about 1400 miles. I smelled the coolant like I have since the beginning, but it was only about 1/2" down when I checked it before I left Granite Bay. I just checked it totally cooled down and it hasn't dropped at all. AND..no smell at all. So, maybe the little gremlins in the system moved to stop the annoying leak in the reservoir? I dunno, but it's nice not smelling that crap.

BTW: I bought an extra reservoir -- just in case. If you can get one cheap they are worth gold to have on hand.

 

So last night I drove a bit with tht e heater on and no leak at all......

These cars can fix themselves!

who knew?

 

This area is near the pump for the supercharger intercooler. You might want to look around it to see if something is loose. Its very tight in there and a leak could be tricky to spot. I suggest removing the filler cap on the intercooler to see if the fluid level is low there. You will need a big fat 15mm hex key.

 

For those who want their own pressure tester, this is the Jaguar XK8 adapter that works with a Stant pressure tester:

Tank Adapter Ford Newer Vehicles ASSENMACHER FZ 37 - Mechanics Tools and Bits

 

Is that the big hex key on the top of the lines going to the supercharger?

Does this fill with coolant from the main cooling system? If not wht do i add?

Is there any maintenance for the Super charger?

THANK YOU!

Chris

 

And it looks like you found the best price, too!

 

You can use a 3/4" Hex Nut. Put a washer or two into the recess in the Cap. Then put the 3/4" nut in the recess so that half of the nut is in the recess and half extends above the Cap. Then use a 3/4" Socket to loosen the Cap.

 

Big thanks on the pressure test adapter. System pressure testers are a much needed tool for these cars...or any with hidden hoses and connections.

 

All "guesses welcome" on my 99 XK8 conv...... A pully broke while on the Highway and I turned around and drove home about 10 miles. After replacing pully, belt and resevoir, filled only with water, as I wanted to " test integrity" the small bleeder hose to the resevoir split, overheating again. I replaced the hose and other upper and lower rad hoses with a 50 / 50 coolant.

The episode has resulted in continued coolant loss and a small amount of engine shake till it warms up. I dont see any exhaust smoke.

Careful exam found a very small seepage at the Therm housing and replaced the O ring gasket and seems perfect.... but still a lot of coolant loss driving only 30-40 miles or less...... Since there are NO visible leaks,,, COULD IT BE

1. Bad head gasket
2. Dripping from heater core hose or connection on hot exhaust pipes
3. some problem in water pump...

What steps to solve the problem would be suggested... Thanks to ALL