[xj-s] Multiple 95/96 AJ16's overheating

Hello all;

Lately there seems to be multiple posts on 95/96 AJ16’s and I think
a some 93-94s as well. The symptoms seem to be the same: going
above the N when pushing hard and on stop and go traffic. Its
happening now that the temps are getting into the 90’s where some
folks are located.

My car has had a couple of new thermostats a couple of new fan
clutches recently, also new foam around the radiator, the flaps on
the radiator cover are all there, and I replaced the ill working
pusher fan with a heavy duty spal 9 inch pusher and a second flat
profile pusher on the other end of the condenser-which I wired to
come on ALL the time. I even traced a couple on NLA, part number
dac11079 temperature senders for the gauge.I added a second ground
to the instrument cluster…I had the radiator removed and ‘‘boiled’’
out…oh yeah and I also ran a direct connection between the temp
sender and the gauge…Fun times…NOT.

Once the temperature hits upper 90’s my gauge still goes beyond
the ‘‘N’’ when pushing hard above 80 on the freeway…when seating on
stop and go too .SIGH.

The only one of these things that I did not do myself is the
radiator boil out. As I have mentioned before I live in a condo
with underground parking. Can’t have fluids all over the place.
Also I was still kind of a novice with the car at that time.

Saturday, I noticed a little bit of coolant on the floor. I think
its probably the medusa /Octopus hose that’s leaking. So I took it
to the shop.Told them to fix the leak and to take out the radiator
and have it recoredwhile we where at it(plus a few other odds
and ends I have not gotten to myself-who says I have to pay the
mortgage this month !!??!!).

At this point I think that there are only three options:

1-The leaking hose has been pinched/malfunctioning all along and
causing the rise in temps-(why would it pinch on stop and go though)

2-The radiator was never really removed and boiled out and the
mechanic who claimed to have had that done took me for a ride

3-The gauge in the cluster is messed up. (but it reads below N
under until the temps get in the upper 90’s)

I have this very unpleasant feeling the answer is #2. I still
remember when I placed new foam around the radiator and replaced
the fan clutch the first time, I removed that top cover and it
seemed like it had never been opened in the past…at least not
recently, which would have had to have done to remove the radiator

This time around its with a different mechanic and of course I am
going to be on top of it and make sure I drop unexpectedly…

The point of this post is I think that we are all having radiator
problems. I have replaced everything I could possibly replace
except the gauge and the radiator.

If a radiator recore does not do the trick then I will get a new
gauge.

I know these cars read below the N when they where new.

I will keep you all posted–
95 AJ16 4liter 6cylinder, Houston TX
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In reply to a message from Mark Janzic sent Sun 26 Jun 2011:

They almost always paint radiators with a thick, shiny, sticky,
black paint when they remove, and boil them, or re-core them, so
that is one thing to look for if you are trying to see if they did
the work they said they did…

Dave
Atlanta–
Penfold99
Atlanta, GA, United States
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In reply to a message from Penfold99 sent Sun 26 Jun 2011:

Dude, really??

I never new that. No mine is not

Yeah, I got punked by the old mechanic.–
95 AJ16 4liter 6cylinder, Houston TX
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In reply to a message from Mark Janzic sent Sun 26 Jun 2011:

I was able to eliminate the octopus hose system when I
installed the AJ16 engine in my 1982 XJS that had the 3.6L
AJ6 engine originally. The 3.6L had a metal pipe going from
the back of the water pump to the heater connections on the
firewall. This metal pipe attaches under the large coolant
hose going from the back of the water pump to the middle of
the block. By combining the 3.6L water routing system and
3.6L water pump with the AJ16 engine seems to work well in
my install.–
Steven A. DuChene - XJ6VDP XJ6C XJ12C XK120SE 3.8S E-Types
Phoenix, AZ Atlanta GA, NE Oh, United States
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In reply to a message from StevenD57 sent Sun 26 Jun 2011:

I hate to mention ths after all the travail.But, guages can be
misleading!! Verify the actual temperature in another way. One is
with a simple infra red meter from good old HF. As long as the
coolant is presnt with no cavaties and the oil is prsent an
occasional slip into yhre low 90 C will not hurt a thing.

I hope the ‘‘new’’ mechanic really rods it and that the core is still
strong enough to take it. Rodding isn’t gentle!

Carl–
Carl Hutchins 1983 Jaguar XJ6 with LT1 and 1994 Jeep Grand
Walnut Creek, California, United States
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In reply to a message from cadjag sent Sun 26 Jun 2011:

This is a welcome thread. My 96 is going through this as
well.

I did have the coolant temp probed when the needle was halfway
between N and H, as it does when it’s over 90 with the AC on.
It read 220.

This is not a gauge problem, this is a real temperature
problem. The temp is fine at highway speeds, just not in city
driving on hot days with the AC on.

I am eager to see where this thread ends up.–
1996 XJS 2+2 Convertible with 4.0L AJ16
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They almost always paint radiators with a thick, shiny,
sticky,
black paint when they remove, and boil them, or re-core
them,

Ask them not to paint it. That paint acts like insulation reducing the transfer of heat.

Geoff Green

95 XJS 4.0 conv, 76 XJ-S, 61 E-type OTS, 05 F250 Turbo Diesel, 10 Escape

Keeping track of every Jaguar XJ-S, with your help.
http://www.xjsdata.com

3.6 XJS Register paulzimmer@btopenworld.com

Eventer Register pascal.mathieu@perso.be

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In reply to a message from Geoffrey Green sent Mon 27 Jun 2011:

Thanks Geoff. I will ask them not to repaint it…–
95 AJ16 4liter 6cylinder, Houston TX
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In reply to a message from Mark Janzic sent Tue 28 Jun 2011:

I have a 95 coupe with the AJ16. I have noticed that the needle
goes just beyond the N when in hot weather, above 80. I left it
sitting in my driveway running for 30 minutes and the needle did
not go much beyond the N. I was worried about this since I have
read every post about overheating. The temperature with the IR
thermometer read 187 F. This did not seem to be too high. Maybe the
AJ16 and the gauge they use do not relate to the 12 cylinders. The
auxilary fan does not come on but it works with direct connection
to the plug. I have to check the temperature sending unit to see if
that is working but have not had the time to check this. I also
wanted to mention that the car ran cooler before I switched to
Mobil 1 synthetic. I don’t why this might happen.

tom
1995 xjs 4.0l coupe–
The original message included these comments:

95 AJ16 4liter 6cylinder, Houston TX


tomjag95
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In reply to a message from tomjag95 sent Tue 28 Jun 2011:

Well the gauges and senders are flaky, but as I pointed in my first
post, I have replaced every single component except the radiator
and the gauge itself and my car does what your car does as well.
Once I get the car back from the shop with the recored radiator I
will be able to tell if it was a radiator or gauge problem–
95 AJ16 4liter 6cylinder, Houston TX
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In reply to a message from Mark Janzic sent Tue 28 Jun 2011:

I am eager to hear what happens…–
1996 XJS 2+2 Convertible with 4.0L AJ16
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In reply to a message from Veekay sent Wed 29 Jun 2011:

Hello, wanted to update on the progress.

The radiator was removed-this time I was there to see it taken out-
and send to be recored-at the radiator shop they found the radiator
to be partially clogged (the alleged rodding out that happened a
year and half ago never really happened). They rodded the radiator
out and insisted it did not need recoring. They say the core is
still working at optimum condition and that the radiator is in
excellent condition. Although I was ready and wanting to pay 600.00
for a recore they insisted the 160.00 rodding is all it needed.

I bought some Jaguar coolant at the dealer and distilled water to
refill.

So basically:

1-I got fooled/punked/made a fool of/insert name here/ by my other
mechanic. The radiator would not be clogged up now if it was rodded
18 months ago or so. He told me he took it out and never really did.

2-No matter how much I offered to pay I have been assured by the
radiator shop that recoring is not necessary. The radiator is in
good shape and has been rodded out for real this time. I guess
their honesty compensates for #1

3-Coolant hoses have been replaced and no more leaks.

4-Pick up the car tomorrow-wish me luck–
95 AJ16 4liter 6cylinder, Houston TX
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Mark Janzic wrote:

So basically:

1-I got fooled/punked/made a fool of/insert name here/ by my other
mechanic. The radiator would not be clogged up now if it was rodded 18
months ago or so. He told me he took it out and never really did.

I guess you have a coolant filter in this circuit? Because if you
don’t, a freshly-rodded radiator could very well have gotten plugged
up in 18 months – or 18 minutes, for that matter. It’s not a
function of time.

– Kirbert

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In reply to a message from Kirbert sent Sat 2 Jul 2011:

In 18 minutes?? How?–
95 AJ16 4liter 6cylinder, Houston TX
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Mark Janzic wrote:

In 18 minutes?? How?

You’ve had a plugged radiator in there, which means no flow. Hence,
whatever junk is floating around in the coolant circuit has just
settled in various nooks and crannies inside the block and head. Now
you install a freshly-rodded radiator and you decide a coolant filter
isn’t necessary right now, maybe you’ll get around to it next year.
You start the engine, and suddenly there is vastly more coolant flow
than it’s seen in years. All that coolant rushing through the block
and head stirs up all that settled crud and gets it moving, and it
moves right into your freshly-rodded radiator. It’s half plugged up
within minutes of the thermostat opening.

– Kirbert

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In reply to a message from Kirbert sent Mon 4 Jul 2011:

Hello everyone.

As I mentioned earlier, the radiator shop insisted my radiator was
in good shape and stongly suggested I stick with a rodding instead
of a recore. They found it was 1/3 rd plugged up

The radiator was reinstalled, new coolant etc.

Same result. Gauge still goes above N. sigh

Back at square one. :>(

My laser thermostat is reading a little over 200 at the thermostat
housing when its completely past the N.

Next step is going to be to buy a new gauge.

If that does not work I will start from the top again begining with
the cheapest thing: the thermostat. A lot of the things on the car
are after-market including the thermostat and fan clutch…also
when the original electric pusher fan died I replaced it with an
aftermarket Spal pusher fan… If a new gauge does not work I
will buy the parts directly from Jaguar and pay the 500 dollars for
the OEM new aux fan and return to the original set up.

Agh!!–
95 AJ16 4liter 6cylinder, Houston TX
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In reply to a message from Mark Janzic sent Wed 6 Jul 2011:

Thank you so much for the continuous updates. I have checked
back here religiously.–
1996 XJS 2+2 Convertible with 4.0L AJ16
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In reply to a message from Veekay sent Wed 6 Jul 2011:

Is there any way the water pump can have anything to do with
this? I checked your history and it doesn’t seem that the
water pump was diagnosed, or replaced.–
1996 XJS 2+2 Convertible with 4.0L AJ16
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In reply to a message from Veekay sent Wed 6 Jul 2011:

Hey Veekay.

Yes the water pump was replaced…

I will post as soon as I get a new gauge in there.–
95 AJ16 4liter 6cylinder, Houston TX
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In reply to a message from Mark Janzic sent Thu 7 Jul 2011:

I’m praying that it’s a simple gauge problem…

My car was shot by my mechanic at 220F when the gauge was
reading 3/4 between N and H, so I don’t think my gauges are
bad.

He did use a infrared though. Maybe it wasn’t calibrated or
something…–
1996 XJS 2+2 Convertible with 4.0L AJ16
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