[xj40] Oil Cooler

Bryan,

Very few vehicles in the States are equipped with engine
oil coolers … automatic transmission oil coolers are
ubiquituous.

Based on the engine sump capacity and the excellent heat
transfer characteristics of aluminum, the cooler is
probably not necessary … but its a fine feature I would
not want to remove unless mandated (leaky cooler, hoses,
etc.)

Its not unusual at all for the ambient temperature in my
area (southeast US) to run in the mid-90s F for extended
periods in the summer. I’ll keep the cooler until it
breaks!

John
P.

I read some time ago a study on oil coolers.
If they are equipped with some sort of thermostatic
device, they are very effective in stabilizing
oil temperatures.

Except in very hot climates, an oil cooler without any
thermostatic control was not shown to be of any benefit,
because the oil would not get up to temperature
as quickly…could even be bad under most conditions…

From what I have read, the Jaguar has a pressure driven bypass
built in the adaptor plate.
High oil pressure closes the cooler off, it opens
when the oil warms up and thins out.

Lots would depend on the oil viscosity in this setup.
Running 20w50 would have it closed until the oil
really warmed up I would guess.
5w50 synthetic might have it open at a cold start
in warm conditions.

Its nice to have a cooler, but since the engine holds
quite a bit of oil, and I change it quite frequently,
its likely of little use in New Jersey or most places
I am likely to drive to.
Still, when you are loaded up with people and luggage,
climbing long grades with the ac on in 100F plus
weather, its nice to have…

Besides leaks, the system is well out of the way on my car
so there is no good reason to remove it.
For the price of a few O rings, most leaks can be fixed.
($2.00)
If a hose leaks, its a different story.

Its always reported that the lines are IMPOSSIBLE to get
off the cooler…I wonder if there is any solution
to this problem…oil and heat?
Perhaps the entire setup could be removed, the old hose
cut off and new hose installed with good clamps?
Its only oil, so hose that would work should be available.

Brett
1990 XJ6>

Based on the engine sump capacity and the excellent heat
transfer characteristics of aluminum, the cooler is
probably not necessary … but its a fine feature I would
not want to remove unless mandated (leaky cooler, hoses,
etc.)

Its not unusual at all for the ambient temperature in my
area (southeast US) to run in the mid-90s F for extended
periods in the summer. I’ll keep the cooler until it
breaks!

John
P.

Hi,
You do not need a bypass pipe,
All you have to do is remove the oil filter, then you can
remove the four bolts that hold the filter housing and then remove
the spacer plate with the cooler lines, refit the oil filter
housing with new shorter bolts, fit a new oil filter, change the
engine oil while your under there.
Job done.

Best regards
Pete Bailey
1990 2.9/3.6 Dual fuel
1991 4.0 Under Full rebuild–
Gasdriver
Staffordshire, United Kingdom
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In reply to a message from Gasdriver sent Mon 7 Jun 2004:

Pete,

As you may have read in my exchange of posts to the forum with
Chris, when doing as you suggest, aren’t you losing the oil filter
by-pass valve which resides in the spacer housing between the
filter head and the block?

If it was that simple, I assume there was some reason why Jaguar
didn’t do it that way. Anyone know?–
The original message included these comments:

  You do not need a bypass pipe,
  All you have to do is remove the oil filter, then you can 

remove the four bolts that hold the filter housing and then remove
the spacer plate with the cooler lines, refit the oil filter
housing with new shorter bolts, fit a new oil filter, change the
engine oil while your under there.


Bryan N ('91 Sovereign 4.0 L)
Cambridge, United Kingdom
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Just finished changing the power steering system over and
eliminating the disconnected rear levellers and now appears to have
an oil leak draining from inside the left wheel well next to the
emissions cannister. It’s dripping from the vent hole in the cover
that hides this cannister. I am in the process of taking this cover
off to see exactly where the leak is. The oil cooler lines look wet
but am not sure if it is the lines,or the O rings that go into the
line housing by the oil filter. Hoses appear to be $2-300 USD.
Question is do I need a cooler or can I just plug it off? I live in
a desert climate and it gets into the 100 degree mark daily. Have
had many cars without cooler for oil. Is this really necessary??
Thanks you guys have helped a lot.–
WIDGET33
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In a message dated 3/23/2006 2:18:21 AM Eastern Standard Time, “VETTEMAN” m.dietz@cox.net writes:

appears to have
an oil leak draining from inside the left wheel well next to the
emissions cannister. It’s dripping from the vent hole in the cover
that hides this cannister. I am in the process of taking this cover
off to see exactly where the leak is. The oil cooler lines look wet
but am not sure if it is the lines,or the O rings that go into the
line housing by the oil filter. Hoses appear to be $2-300 USD.
Question is do I need a cooler or can I just plug it off? I live in
a desert climate and it gets into the 100 degree mark daily.

Personally, I would keep the oil cooler, for better engine lubrication and longer bearing life. Hot oil (particularly in hot climates) doesn’t lubricate nearly as well as warm oil.

The o-rings (CAC5118) at the filter head are $1.25 each from Motorcars and probably available from any good auto parts store locally matching size, or if the rubber hose is leaking, a hose/hydraulic shop can replace the rubber for a lot less than $100. You can do it yourself if you can get the right size & spec replacement hose. Just cut off the crimped fitting where the hose attaches to the metal pipe, using an air cutter or hacksaw, and attach the new hose with hose clamps.

George Balthrop, Clifton, VA USA
85 & 89 XJ-S Coupes; 89 XJ40 VDP

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In reply to a message from VETTEMAN sent Thu 23 Mar 2006:

you did not say what is leaking. engine oil? and yes the oil
cooler is a must for longevity. pajtas–
jaguarjoe 54 XK 120 rdstr 1961 MKIX 94 XJ6
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I only use my 1988 XJ40 occasionally as a weekend car. I came to
start her up to day and noticed an oil leak.

At best the seal on one of the Oil Cooler unions has failed, or at
worst the Cooler itself.

However I can�t free the pipes from the cooler, they appear to be
completely seized, adding any more leverage probably will damage
something.

Has any one any similar experiences?

Thanks
Jamie
WALES UK–
ghound
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In reply to a message from ghound sent Sun 31 Dec 2006:

A common problem when trying to remove the engine oil cooler
lines from the cooler itself.

Jamie

The simple solution is to dispense with the oil cooler
completely (as Jaguar did on later models of XJ40).

To do that, all that you need to do is remove the oil
filter, the oil filter head and the oil cooler adaptor
between that and the block, and, using shorter bolts, simply
bolt the oil filter head directly on to the block and re-fit
the filter.

You can then wrestle the oil cooler off the car complete
with pipes. In all but the most severe temperatures, the oil
cooler is superfluous - and I don’t think you will need it
in Wales–
The original message included these comments:

I only use my 1988 XJ40 occasionally as a weekend car. I came to
start her up to day and noticed an oil leak.
At best the seal on one of the Oil Cooler unions has failed, or at
worst the Cooler itself.
However I can�t free the pipes from the cooler, they appear to be
completely seized, adding any more leverage probably will damage
something.
Has any one any similar experiences?


Bryan N, '91 Sovereign 4.0 L, (RHD)
Cambridge, United Kingdom
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In reply to a message from ghound sent Sun 31 Dec 2006:

Thanks Bryan.

That�s good news. Would you know if it�s possible to do this from
underneath with the car on axle stands?

Jamie–
ghound
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In reply to a message from ghound sent Sun 31 Dec 2006:

Jamie,

Yes, should be relatively easy. The oil filter head / cooler
adaptor is easily accessible from below. Measure the
thickness of the adaptor and get new bolts that much shorter
than the originals.

Of course, you can leave the oil cooler in place if you like

  • just cut the pipes and blank them off.–
    The original message included these comments:

That�s good news. Would you know if it�s possible to do this from
underneath with the car on axle stands?


Bryan N, '91 Sovereign 4.0 L, (RHD)
Cambridge, United Kingdom
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In reply to a message from Bryan N sent Sun 31 Dec 2006:

one trick I have used to shorten bolts is to screw on a couple nuts
past the point where you will cut the bolt…i use a Dremel cut-
off disc to cut off the extra length of the bolt and cut at a
slight angle that mimics the angle of the threads…then I slowly
unscrew the nuts from the bolt…removing the nuts will repair any
damage to the bolt threads when you cut the extra length off…–
The original message included these comments:

adaptor is easily accessible from below. Measure the
thickness of the adaptor and get new bolts that much shorter
than the originals.


Cliff - '93 XJ40 Sovereign (4.0L)
Lancaster/South Carolina, United States
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In reply to a message from Cliff Archie sent Tue 2 Jan 2007:

Cliff,

Unfortunately, that procedure won’t work on these particular
bolts.

They are part number FB108141J and that translates as a
‘Flange head bolt’ (FB) - i.e the shank is only threaded
for part of its length [as opposed to a ‘Flange head screw’
(FS) which is threaded over its full length].

The original bolt is an M8 (from the fourth and fifth
characters ‘08’) and 70 mm long (from the sixth and seventh
characters - ‘14’ x 5mm). The 8 mm thread probably covers
the first 30 mm only, so to shorten and re-use the original
bolts would require the thread to be cut further down the
shank before it is cut off to the required length.

But, if you have access to a metric die then that is
probably a good solution.–
The original message included these comments:

one trick I have used to shorten bolts is to screw on a couple nuts
past the point where you will cut the bolt…i use a Dremel cut-
off disc to cut off the extra length of the bolt and cut at a
slight angle that mimics the angle of the threads…then I slowly
unscrew the nuts from the bolt…removing the nuts will repair any
damage to the bolt threads when you cut the extra length off…


Bryan N, '91 Sovereign 4.0 L, (RHD)
Cambridge, United Kingdom
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I followed Bryan’s instructions and managed to remove the oil cooler pretty easily.

I must say this forum is great! With the advises on this forum and Jag Lovers Ebook I have been able to do the vacuum brake booster conversion, blower motor repair, digital instrument cluster repair, water pump to water rail hose replacement (that famous hose that fails), windscreen wiper assembly repair (replaced the micro switch), and real differential oil change (I followed the tip about getting the new oil in through the hole in the boot).

Currently I am about to replace the thermal expansion valve and I have acquired a crowfoot wrench to make it possible as suggested on this forum. I am also replacing the oxygen sensor. It just does not work loose, so I guess I have to remove it roughly and weld a weld-on nut for the new sensor.